xref: /petsc/src/mat/impls/aij/seq/aijfact.c (revision 0fa040f91fc0ebe4f74b7f63f2221f0edf4da5a7)
1 #define PETSCMAT_DLL
2 
3 
4 #include "../src/mat/impls/aij/seq/aij.h"
5 #include "../src/mat/impls/sbaij/seq/sbaij.h"
6 #include "petscbt.h"
7 #include "../src/mat/utils/freespace.h"
8 
9 EXTERN_C_BEGIN
10 #undef __FUNCT__
11 #define __FUNCT__ "MatOrdering_Flow_SeqAIJ"
12 /*
13       Computes an ordering to get most of the large numerical values in the lower triangular part of the matrix
14 */
15 PetscErrorCode MatOrdering_Flow_SeqAIJ(Mat mat,const MatOrderingType type,IS *irow,IS *icol)
16 {
17   Mat_SeqAIJ        *a = (Mat_SeqAIJ*)mat->data;
18   PetscErrorCode    ierr;
19   PetscInt          i,j,jj,k, kk,n = mat->rmap->n, current = 0, newcurrent = 0,*order;
20   const PetscInt    *ai = a->i, *aj = a->j;
21   const PetscScalar *aa = a->a;
22   PetscTruth        *done;
23   PetscReal         best,past = 0,future;
24 
25   PetscFunctionBegin;
26   /* pick initial row */
27   best = -1;
28   for (i=0; i<n; i++) {
29     future = 0.0;
30     for (j=ai[i]; j<ai[i+1]; j++) {
31       if (aj[j] != i) future  += PetscAbsScalar(aa[j]); else past = PetscAbsScalar(aa[j]);
32     }
33     if (!future) future = 1.e-10; /* if there is zero in the upper diagonal part want to rank this row high */
34     if (past/future > best) {
35       best = past/future;
36       current = i;
37     }
38   }
39 
40   ierr = PetscMalloc(n*sizeof(PetscTruth),&done);CHKERRQ(ierr);
41   ierr = PetscMemzero(done,n*sizeof(PetscTruth));CHKERRQ(ierr);
42   ierr = PetscMalloc(n*sizeof(PetscInt),&order);CHKERRQ(ierr);
43   order[0] = current;
44   for (i=0; i<n-1; i++) {
45     done[current] = PETSC_TRUE;
46     best          = -1;
47     /* loop over all neighbors of current pivot */
48     for (j=ai[current]; j<ai[current+1]; j++) {
49       jj = aj[j];
50       if (done[jj]) continue;
51       /* loop over columns of potential next row computing weights for below and above diagonal */
52       past = future = 0.0;
53       for (k=ai[jj]; k<ai[jj+1]; k++) {
54         kk = aj[k];
55         if (done[kk]) past += PetscAbsScalar(aa[k]);
56         else if (kk != jj) future  += PetscAbsScalar(aa[k]);
57       }
58       if (!future) future = 1.e-10; /* if there is zero in the upper diagonal part want to rank this row high */
59       if (past/future > best) {
60         best = past/future;
61         newcurrent = jj;
62       }
63     }
64     if (best == -1) { /* no neighbors to select from so select best of all that remain */
65       best = -1;
66       for (k=0; k<n; k++) {
67         if (done[k]) continue;
68         future = 0.0;
69         past   = 0.0;
70         for (j=ai[k]; j<ai[k+1]; j++) {
71           kk = aj[j];
72           if (done[kk]) past += PetscAbsScalar(aa[j]);
73           else if (kk != k) future  += PetscAbsScalar(aa[j]);
74         }
75         if (!future) future = 1.e-10; /* if there is zero in the upper diagonal part want to rank this row high */
76         if (past/future > best) {
77           best = past/future;
78           newcurrent = k;
79         }
80       }
81     }
82     if (current == newcurrent) SETERRQ(PETSC_ERR_PLIB,"newcurrent cannot be current");
83     current = newcurrent;
84     order[i+1] = current;
85   }
86   ierr = ISCreateGeneral(PETSC_COMM_SELF,n,order,irow);CHKERRQ(ierr);
87   *icol = *irow;
88   ierr = PetscObjectReference((PetscObject)*irow);CHKERRQ(ierr);
89   ierr = PetscFree(done);CHKERRQ(ierr);
90   ierr = PetscFree(order);CHKERRQ(ierr);
91   PetscFunctionReturn(0);
92 }
93 EXTERN_C_END
94 
95 EXTERN_C_BEGIN
96 #undef __FUNCT__
97 #define __FUNCT__ "MatGetFactorAvailable_seqaij_petsc"
98 PetscErrorCode MatGetFactorAvailable_seqaij_petsc(Mat A,MatFactorType ftype,PetscTruth *flg)
99 {
100   PetscFunctionBegin;
101   *flg = PETSC_TRUE;
102   PetscFunctionReturn(0);
103 }
104 EXTERN_C_END
105 
106 EXTERN_C_BEGIN
107 #undef __FUNCT__
108 #define __FUNCT__ "MatGetFactor_seqaij_petsc"
109 PetscErrorCode MatGetFactor_seqaij_petsc(Mat A,MatFactorType ftype,Mat *B)
110 {
111   PetscInt           n = A->rmap->n;
112   PetscErrorCode     ierr;
113 
114   PetscFunctionBegin;
115   ierr = MatCreate(((PetscObject)A)->comm,B);CHKERRQ(ierr);
116   ierr = MatSetSizes(*B,n,n,n,n);CHKERRQ(ierr);
117   if (ftype == MAT_FACTOR_LU || ftype == MAT_FACTOR_ILU || ftype == MAT_FACTOR_ILUDT){
118     ierr = MatSetType(*B,MATSEQAIJ);CHKERRQ(ierr);
119     (*B)->ops->ilufactorsymbolic = MatILUFactorSymbolic_SeqAIJ;
120     (*B)->ops->lufactorsymbolic  = MatLUFactorSymbolic_SeqAIJ;
121   } else if (ftype == MAT_FACTOR_CHOLESKY || ftype == MAT_FACTOR_ICC) {
122     ierr = MatSetType(*B,MATSEQSBAIJ);CHKERRQ(ierr);
123     ierr = MatSeqSBAIJSetPreallocation(*B,1,MAT_SKIP_ALLOCATION,PETSC_NULL);CHKERRQ(ierr);
124     (*B)->ops->iccfactorsymbolic      = MatICCFactorSymbolic_SeqAIJ;
125     (*B)->ops->choleskyfactorsymbolic = MatCholeskyFactorSymbolic_SeqAIJ;
126   } else SETERRQ(PETSC_ERR_SUP,"Factor type not supported");
127   (*B)->factor = ftype;
128   PetscFunctionReturn(0);
129 }
130 EXTERN_C_END
131 
132 #undef __FUNCT__
133 #define __FUNCT__ "MatLUFactorSymbolic_SeqAIJ_inplace"
134 PetscErrorCode MatLUFactorSymbolic_SeqAIJ_inplace(Mat B,Mat A,IS isrow,IS iscol,const MatFactorInfo *info)
135 {
136   Mat_SeqAIJ         *a = (Mat_SeqAIJ*)A->data,*b;
137   IS                 isicol;
138   PetscErrorCode     ierr;
139   const PetscInt     *r,*ic;
140   PetscInt           i,n=A->rmap->n,*ai=a->i,*aj=a->j;
141   PetscInt           *bi,*bj,*ajtmp;
142   PetscInt           *bdiag,row,nnz,nzi,reallocs=0,nzbd,*im;
143   PetscReal          f;
144   PetscInt           nlnk,*lnk,k,**bi_ptr;
145   PetscFreeSpaceList free_space=PETSC_NULL,current_space=PETSC_NULL;
146   PetscBT            lnkbt;
147 
148   PetscFunctionBegin;
149   if (A->rmap->N != A->cmap->N) SETERRQ(PETSC_ERR_ARG_WRONG,"matrix must be square");
150   ierr = ISInvertPermutation(iscol,PETSC_DECIDE,&isicol);CHKERRQ(ierr);
151   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
152   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
153 
154   /* get new row pointers */
155   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bi);CHKERRQ(ierr);
156   bi[0] = 0;
157 
158   /* bdiag is location of diagonal in factor */
159   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bdiag);CHKERRQ(ierr);
160   bdiag[0] = 0;
161 
162   /* linked list for storing column indices of the active row */
163   nlnk = n + 1;
164   ierr = PetscLLCreate(n,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
165 
166   ierr = PetscMalloc2(n+1,PetscInt**,&bi_ptr,n+1,PetscInt,&im);CHKERRQ(ierr);
167 
168   /* initial FreeSpace size is f*(ai[n]+1) */
169   f = info->fill;
170   ierr = PetscFreeSpaceGet((PetscInt)(f*(ai[n]+1)),&free_space);CHKERRQ(ierr);
171   current_space = free_space;
172 
173   for (i=0; i<n; i++) {
174     /* copy previous fill into linked list */
175     nzi = 0;
176     nnz = ai[r[i]+1] - ai[r[i]];
177     if (!nnz) SETERRQ2(PETSC_ERR_MAT_LU_ZRPVT,"Empty row in matrix: row in original ordering %D in permuted ordering %D",r[i],i);
178     ajtmp = aj + ai[r[i]];
179     ierr = PetscLLAddPerm(nnz,ajtmp,ic,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
180     nzi += nlnk;
181 
182     /* add pivot rows into linked list */
183     row = lnk[n];
184     while (row < i) {
185       nzbd    = bdiag[row] - bi[row] + 1; /* num of entries in the row with column index <= row */
186       ajtmp   = bi_ptr[row] + nzbd; /* points to the entry next to the diagonal */
187       ierr = PetscLLAddSortedLU(ajtmp,row,nlnk,lnk,lnkbt,i,nzbd,im);CHKERRQ(ierr);
188       nzi += nlnk;
189       row  = lnk[row];
190     }
191     bi[i+1] = bi[i] + nzi;
192     im[i]   = nzi;
193 
194     /* mark bdiag */
195     nzbd = 0;
196     nnz  = nzi;
197     k    = lnk[n];
198     while (nnz-- && k < i){
199       nzbd++;
200       k = lnk[k];
201     }
202     bdiag[i] = bi[i] + nzbd;
203 
204     /* if free space is not available, make more free space */
205     if (current_space->local_remaining<nzi) {
206       nnz = (n - i)*nzi; /* estimated and max additional space needed */
207       ierr = PetscFreeSpaceGet(nnz,&current_space);CHKERRQ(ierr);
208       reallocs++;
209     }
210 
211     /* copy data into free space, then initialize lnk */
212     ierr = PetscLLClean(n,n,nzi,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
213     bi_ptr[i] = current_space->array;
214     current_space->array           += nzi;
215     current_space->local_used      += nzi;
216     current_space->local_remaining -= nzi;
217   }
218 #if defined(PETSC_USE_INFO)
219   if (ai[n] != 0) {
220     PetscReal af = ((PetscReal)bi[n])/((PetscReal)ai[n]);
221     ierr = PetscInfo3(A,"Reallocs %D Fill ratio:given %G needed %G\n",reallocs,f,af);CHKERRQ(ierr);
222     ierr = PetscInfo1(A,"Run with -pc_factor_fill %G or use \n",af);CHKERRQ(ierr);
223     ierr = PetscInfo1(A,"PCFactorSetFill(pc,%G);\n",af);CHKERRQ(ierr);
224     ierr = PetscInfo(A,"for best performance.\n");CHKERRQ(ierr);
225   } else {
226     ierr = PetscInfo(A,"Empty matrix\n");CHKERRQ(ierr);
227   }
228 #endif
229 
230   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
231   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
232 
233   /* destroy list of free space and other temporary array(s) */
234   ierr = PetscMalloc((bi[n]+1)*sizeof(PetscInt),&bj);CHKERRQ(ierr);
235   ierr = PetscFreeSpaceContiguous(&free_space,bj);CHKERRQ(ierr);
236   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
237   ierr = PetscFree2(bi_ptr,im);CHKERRQ(ierr);
238 
239   /* put together the new matrix */
240   ierr = MatSeqAIJSetPreallocation_SeqAIJ(B,MAT_SKIP_ALLOCATION,PETSC_NULL);CHKERRQ(ierr);
241   ierr = PetscLogObjectParent(B,isicol);CHKERRQ(ierr);
242   b    = (Mat_SeqAIJ*)(B)->data;
243   b->free_a       = PETSC_TRUE;
244   b->free_ij      = PETSC_TRUE;
245   b->singlemalloc = PETSC_FALSE;
246   ierr          = PetscMalloc((bi[n]+1)*sizeof(PetscScalar),&b->a);CHKERRQ(ierr);
247   b->j          = bj;
248   b->i          = bi;
249   b->diag       = bdiag;
250   b->ilen       = 0;
251   b->imax       = 0;
252   b->row        = isrow;
253   b->col        = iscol;
254   ierr          = PetscObjectReference((PetscObject)isrow);CHKERRQ(ierr);
255   ierr          = PetscObjectReference((PetscObject)iscol);CHKERRQ(ierr);
256   b->icol       = isicol;
257   ierr          = PetscMalloc((n+1)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
258 
259   /* In b structure:  Free imax, ilen, old a, old j.  Allocate solve_work, new a, new j */
260   ierr = PetscLogObjectMemory(B,(bi[n]-n)*(sizeof(PetscInt)+sizeof(PetscScalar)));CHKERRQ(ierr);
261   b->maxnz = b->nz = bi[n] ;
262 
263   (B)->factor                = MAT_FACTOR_LU;
264   (B)->info.factor_mallocs   = reallocs;
265   (B)->info.fill_ratio_given = f;
266 
267   if (ai[n]) {
268     (B)->info.fill_ratio_needed = ((PetscReal)bi[n])/((PetscReal)ai[n]);
269   } else {
270     (B)->info.fill_ratio_needed = 0.0;
271   }
272   (B)->ops->lufactornumeric  = MatLUFactorNumeric_SeqAIJ_inplace;
273   (B)->ops->solve            = MatSolve_SeqAIJ_inplace;
274   (B)->ops->solvetranspose   = MatSolveTranspose_SeqAIJ_inplace;
275   /* switch to inodes if appropriate */
276   ierr = MatLUFactorSymbolic_SeqAIJ_Inode(B,A,isrow,iscol,info);CHKERRQ(ierr);
277   PetscFunctionReturn(0);
278 }
279 
280 #undef __FUNCT__
281 #define __FUNCT__ "MatLUFactorSymbolic_SeqAIJ"
282 PetscErrorCode MatLUFactorSymbolic_SeqAIJ(Mat B,Mat A,IS isrow,IS iscol,const MatFactorInfo *info)
283 {
284   Mat_SeqAIJ         *a = (Mat_SeqAIJ*)A->data,*b;
285   IS                 isicol;
286   PetscErrorCode     ierr;
287   const PetscInt     *r,*ic;
288   PetscInt           i,n=A->rmap->n,*ai=a->i,*aj=a->j;
289   PetscInt           *bi,*bj,*ajtmp;
290   PetscInt           *bdiag,row,nnz,nzi,reallocs=0,nzbd,*im;
291   PetscReal          f;
292   PetscInt           nlnk,*lnk,k,**bi_ptr;
293   PetscFreeSpaceList free_space=PETSC_NULL,current_space=PETSC_NULL;
294   PetscBT            lnkbt;
295 
296   PetscFunctionBegin;
297   if (A->rmap->N != A->cmap->N) SETERRQ(PETSC_ERR_ARG_WRONG,"matrix must be square");
298   ierr = ISInvertPermutation(iscol,PETSC_DECIDE,&isicol);CHKERRQ(ierr);
299   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
300   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
301 
302   /* get new row and diagonal pointers, must be allocated separately because they will be given to the Mat_SeqAIJ and freed separately */
303   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bi);CHKERRQ(ierr);
304   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bdiag);CHKERRQ(ierr);
305   bi[0] = bdiag[0] = 0;
306 
307   /* linked list for storing column indices of the active row */
308   nlnk = n + 1;
309   ierr = PetscLLCreate(n,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
310 
311   ierr = PetscMalloc2(n+1,PetscInt**,&bi_ptr,n+1,PetscInt,&im);CHKERRQ(ierr);
312 
313   /* initial FreeSpace size is f*(ai[n]+1) */
314   f = info->fill;
315   ierr = PetscFreeSpaceGet((PetscInt)(f*(ai[n]+1)),&free_space);CHKERRQ(ierr);
316   current_space = free_space;
317 
318   for (i=0; i<n; i++) {
319     /* copy previous fill into linked list */
320     nzi = 0;
321     nnz = ai[r[i]+1] - ai[r[i]];
322     if (!nnz) SETERRQ2(PETSC_ERR_MAT_LU_ZRPVT,"Empty row in matrix: row in original ordering %D in permuted ordering %D",r[i],i);
323     ajtmp = aj + ai[r[i]];
324     ierr = PetscLLAddPerm(nnz,ajtmp,ic,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
325     nzi += nlnk;
326 
327     /* add pivot rows into linked list */
328     row = lnk[n];
329     while (row < i){
330       nzbd  = bdiag[row] + 1; /* num of entries in the row with column index <= row */
331       ajtmp = bi_ptr[row] + nzbd; /* points to the entry next to the diagonal */
332       ierr  = PetscLLAddSortedLU(ajtmp,row,nlnk,lnk,lnkbt,i,nzbd,im);CHKERRQ(ierr);
333       nzi  += nlnk;
334       row   = lnk[row];
335     }
336     bi[i+1] = bi[i] + nzi;
337     im[i]   = nzi;
338 
339     /* mark bdiag */
340     nzbd = 0;
341     nnz  = nzi;
342     k    = lnk[n];
343     while (nnz-- && k < i){
344       nzbd++;
345       k = lnk[k];
346     }
347     bdiag[i] = nzbd; /* note: bdiag[i] = nnzL as input for PetscFreeSpaceContiguous_LU() */
348 
349     /* if free space is not available, make more free space */
350     if (current_space->local_remaining<nzi) {
351       nnz = 2*(n - i)*nzi; /* estimated and max additional space needed */
352       ierr = PetscFreeSpaceGet(nnz,&current_space);CHKERRQ(ierr);
353       reallocs++;
354     }
355 
356     /* copy data into free space, then initialize lnk */
357     ierr = PetscLLClean(n,n,nzi,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
358     bi_ptr[i] = current_space->array;
359     current_space->array           += nzi;
360     current_space->local_used      += nzi;
361     current_space->local_remaining -= nzi;
362   }
363 #if defined(PETSC_USE_INFO)
364   if (ai[n] != 0) {
365     PetscReal af = ((PetscReal)bi[n])/((PetscReal)ai[n]);
366     ierr = PetscInfo3(A,"Reallocs %D Fill ratio:given %G needed %G\n",reallocs,f,af);CHKERRQ(ierr);
367     ierr = PetscInfo1(A,"Run with -pc_factor_fill %G or use \n",af);CHKERRQ(ierr);
368     ierr = PetscInfo1(A,"PCFactorSetFill(pc,%G);\n",af);CHKERRQ(ierr);
369     ierr = PetscInfo(A,"for best performance.\n");CHKERRQ(ierr);
370   } else {
371     ierr = PetscInfo(A,"Empty matrix\n");CHKERRQ(ierr);
372   }
373 #endif
374 
375   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
376   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
377 
378   /* destroy list of free space and other temporary array(s) */
379   ierr = PetscMalloc((bi[n]+1)*sizeof(PetscInt),&bj);CHKERRQ(ierr);
380   ierr = PetscFreeSpaceContiguous_LU(&free_space,bj,n,bi,bdiag);CHKERRQ(ierr);
381   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
382   ierr = PetscFree2(bi_ptr,im);CHKERRQ(ierr);
383 
384   /* put together the new matrix */
385   ierr = MatSeqAIJSetPreallocation_SeqAIJ(B,MAT_SKIP_ALLOCATION,PETSC_NULL);CHKERRQ(ierr);
386   ierr = PetscLogObjectParent(B,isicol);CHKERRQ(ierr);
387   b    = (Mat_SeqAIJ*)(B)->data;
388   b->free_a       = PETSC_TRUE;
389   b->free_ij      = PETSC_TRUE;
390   b->singlemalloc = PETSC_FALSE;
391   ierr = PetscMalloc((bdiag[0]+1)*sizeof(PetscScalar),&b->a);CHKERRQ(ierr);
392   b->j          = bj;
393   b->i          = bi;
394   b->diag       = bdiag;
395   b->ilen       = 0;
396   b->imax       = 0;
397   b->row        = isrow;
398   b->col        = iscol;
399   ierr          = PetscObjectReference((PetscObject)isrow);CHKERRQ(ierr);
400   ierr          = PetscObjectReference((PetscObject)iscol);CHKERRQ(ierr);
401   b->icol       = isicol;
402   ierr          = PetscMalloc((n+1)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
403 
404   /* In b structure:  Free imax, ilen, old a, old j.  Allocate solve_work, new a, new j */
405   ierr = PetscLogObjectMemory(B,(bdiag[0]+1)*(sizeof(PetscInt)+sizeof(PetscScalar)));CHKERRQ(ierr);
406   b->maxnz = b->nz = bdiag[0]+1;
407   B->factor                = MAT_FACTOR_LU;
408   B->info.factor_mallocs   = reallocs;
409   B->info.fill_ratio_given = f;
410 
411   if (ai[n]) {
412     B->info.fill_ratio_needed = ((PetscReal)(bdiag[0]+1))/((PetscReal)ai[n]);
413   } else {
414     B->info.fill_ratio_needed = 0.0;
415   }
416   B->ops->lufactornumeric = MatLUFactorNumeric_SeqAIJ;
417   /* switch to inodes if appropriate */
418   ierr = Mat_CheckInode_FactorLU(B,PETSC_FALSE);CHKERRQ(ierr);
419   PetscFunctionReturn(0);
420 }
421 
422 /*
423     Trouble in factorization, should we dump the original matrix?
424 */
425 #undef __FUNCT__
426 #define __FUNCT__ "MatFactorDumpMatrix"
427 PetscErrorCode MatFactorDumpMatrix(Mat A)
428 {
429   PetscErrorCode ierr;
430   PetscTruth     flg = PETSC_FALSE;
431 
432   PetscFunctionBegin;
433   ierr = PetscOptionsGetTruth(PETSC_NULL,"-mat_factor_dump_on_error",&flg,PETSC_NULL);CHKERRQ(ierr);
434   if (flg) {
435     PetscViewer viewer;
436     char        filename[PETSC_MAX_PATH_LEN];
437 
438     ierr = PetscSNPrintf(filename,PETSC_MAX_PATH_LEN,"matrix_factor_error.%d",PetscGlobalRank);CHKERRQ(ierr);
439     ierr = PetscViewerBinaryOpen(((PetscObject)A)->comm,filename,FILE_MODE_WRITE,&viewer);CHKERRQ(ierr);
440     ierr = MatView(A,viewer);CHKERRQ(ierr);
441     ierr = PetscViewerDestroy(viewer);CHKERRQ(ierr);
442   }
443   PetscFunctionReturn(0);
444 }
445 
446 #undef __FUNCT__
447 #define __FUNCT__ "MatLUFactorNumeric_SeqAIJ"
448 PetscErrorCode MatLUFactorNumeric_SeqAIJ(Mat B,Mat A,const MatFactorInfo *info)
449 {
450   Mat              C=B;
451   Mat_SeqAIJ       *a=(Mat_SeqAIJ*)A->data,*b=(Mat_SeqAIJ *)C->data;
452   IS               isrow = b->row,isicol = b->icol;
453   PetscErrorCode   ierr;
454   const PetscInt   *r,*ic,*ics;
455   const PetscInt   n=A->rmap->n,*ai=a->i,*aj=a->j,*bi=b->i,*bj=b->j,*bdiag=b->diag;
456   PetscInt         i,j,k,nz,nzL,row,*pj;
457   const PetscInt   *ajtmp,*bjtmp;
458   MatScalar        *rtmp,*pc,multiplier,*pv;
459   const  MatScalar *aa=a->a,*v;
460   PetscTruth       row_identity,col_identity;
461 
462   FactorShiftCtx sctx;
463   PetscInt       *ddiag;
464   PetscReal      rs;
465   MatScalar      d;
466 
467   PetscFunctionBegin;
468   /* MatPivotSetUp(): initialize shift context sctx */
469   ierr = PetscMemzero(&sctx,sizeof(FactorShiftCtx));CHKERRQ(ierr);
470 
471   /* if both shift schemes are chosen by user, only use info->shiftpd */
472   if (info->shiftpd) { /* set sctx.shift_top=max{rs} */
473     ddiag          = a->diag;
474     sctx.shift_top = info->zeropivot;
475     for (i=0; i<n; i++) {
476       /* calculate sum(|aij|)-RealPart(aii), amt of shift needed for this row */
477       d  = (aa)[ddiag[i]];
478       rs = -PetscAbsScalar(d) - PetscRealPart(d);
479       v  = aa+ai[i];
480       nz = ai[i+1] - ai[i];
481       for (j=0; j<nz; j++)
482 	rs += PetscAbsScalar(v[j]);
483       if (rs>sctx.shift_top) sctx.shift_top = rs;
484     }
485     sctx.shift_top   *= 1.1;
486     sctx.nshift_max   = 5;
487     sctx.shift_lo     = 0.;
488     sctx.shift_hi     = 1.;
489   }
490 
491   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
492   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
493   ierr = PetscMalloc((n+1)*sizeof(MatScalar),&rtmp);CHKERRQ(ierr);
494   ics  = ic;
495 
496   do {
497     sctx.useshift = PETSC_FALSE;
498     for (i=0; i<n; i++){
499       /* zero rtmp */
500       /* L part */
501       nz    = bi[i+1] - bi[i];
502       bjtmp = bj + bi[i];
503       for  (j=0; j<nz; j++) rtmp[bjtmp[j]] = 0.0;
504 
505       /* U part */
506       nz = bdiag[i]-bdiag[i+1];
507       bjtmp = bj + bdiag[i+1]+1;
508       for  (j=0; j<nz; j++) rtmp[bjtmp[j]] = 0.0;
509 
510       /* load in initial (unfactored row) */
511       nz    = ai[r[i]+1] - ai[r[i]];
512       ajtmp = aj + ai[r[i]];
513       v     = aa + ai[r[i]];
514       for (j=0; j<nz; j++) {
515         rtmp[ics[ajtmp[j]]] = v[j];
516       }
517       /* ZeropivotApply() */
518       rtmp[i] += sctx.shift_amount;  /* shift the diagonal of the matrix */
519 
520       /* elimination */
521       bjtmp = bj + bi[i];
522       row   = *bjtmp++;
523       nzL   = bi[i+1] - bi[i];
524       for(k=0; k < nzL;k++) {
525         pc = rtmp + row;
526         if (*pc != 0.0) {
527           pv         = b->a + bdiag[row];
528           multiplier = *pc * (*pv);
529           *pc        = multiplier;
530           pj = b->j + bdiag[row+1]+1; /* beginning of U(row,:) */
531 	  pv = b->a + bdiag[row+1]+1;
532 	  nz = bdiag[row]-bdiag[row+1]-1; /* num of entries in U(row,:) excluding diag */
533           for (j=0; j<nz; j++) rtmp[pj[j]] -= multiplier * pv[j];
534           ierr = PetscLogFlops(2.0*nz);CHKERRQ(ierr);
535         }
536         row = *bjtmp++;
537       }
538 
539       /* finished row so stick it into b->a */
540       rs = 0.0;
541       /* L part */
542       pv   = b->a + bi[i] ;
543       pj   = b->j + bi[i] ;
544       nz   = bi[i+1] - bi[i];
545       for (j=0; j<nz; j++) {
546         pv[j] = rtmp[pj[j]]; rs += PetscAbsScalar(pv[j]);
547       }
548 
549       /* U part */
550       pv = b->a + bdiag[i+1]+1;
551       pj = b->j + bdiag[i+1]+1;
552       nz = bdiag[i] - bdiag[i+1]-1;
553       for (j=0; j<nz; j++) {
554         pv[j] = rtmp[pj[j]]; rs += PetscAbsScalar(pv[j]);
555       }
556 
557       /* MatPivotCheck() */
558       sctx.rs  = rs;
559       sctx.pv  = rtmp[i];
560       if (info->shiftnz){
561         ierr = MatPivotCheck_nz(info,sctx,i);CHKERRQ(ierr);
562       } else if (info->shiftpd){
563         ierr = MatPivotCheck_pd(info,sctx,i);CHKERRQ(ierr);
564       } else if (info->shiftinblocks){
565         ierr = MatPivotCheck_inblocks(info,sctx,i);CHKERRQ(ierr);
566       } else {
567         ierr = MatPivotCheck_none(info,sctx,i);CHKERRQ(ierr);
568       }
569       rtmp[i] = sctx.pv;
570 
571       /* Mark diagonal and invert diagonal for simplier triangular solves */
572       pv  = b->a + bdiag[i];
573       *pv = 1.0/rtmp[i];
574 
575     } /* endof for (i=0; i<n; i++){ */
576 
577     /* MatPivotRefine() */
578     if (info->shiftpd && !sctx.useshift && sctx.shift_fraction>0 && sctx.nshift<sctx.nshift_max){
579       /*
580        * if no shift in this attempt & shifting & started shifting & can refine,
581        * then try lower shift
582        */
583       sctx.shift_hi       = sctx.shift_fraction;
584       sctx.shift_fraction = (sctx.shift_hi+sctx.shift_lo)/2.;
585       sctx.shift_amount   = sctx.shift_fraction * sctx.shift_top;
586       sctx.useshift        = PETSC_TRUE;
587       sctx.nshift++;
588     }
589   } while (sctx.useshift);
590 
591   ierr = PetscFree(rtmp);CHKERRQ(ierr);
592   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
593   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
594   if (b->inode.use){
595     C->ops->solve   = MatSolve_SeqAIJ_Inode;
596   } else {
597     ierr = ISIdentity(isrow,&row_identity);CHKERRQ(ierr);
598     ierr = ISIdentity(isicol,&col_identity);CHKERRQ(ierr);
599     if (row_identity && col_identity) {
600       C->ops->solve = MatSolve_SeqAIJ_NaturalOrdering;
601     } else {
602       C->ops->solve = MatSolve_SeqAIJ;
603     }
604   }
605   C->ops->solveadd           = MatSolveAdd_SeqAIJ;
606   C->ops->solvetranspose     = MatSolveTranspose_SeqAIJ;
607   C->ops->solvetransposeadd  = MatSolveTransposeAdd_SeqAIJ;
608   C->ops->matsolve           = MatMatSolve_SeqAIJ;
609   C->assembled    = PETSC_TRUE;
610   C->preallocated = PETSC_TRUE;
611   ierr = PetscLogFlops(C->cmap->n);CHKERRQ(ierr);
612 
613   /* MatPivotView() */
614   if (sctx.nshift){
615     if (info->shiftpd) {
616       ierr = PetscInfo4(A,"number of shift_pd tries %D, shift_amount %G, diagonal shifted up by %e fraction top_value %e\n",sctx.nshift,sctx.shift_amount,sctx.shift_fraction,sctx.shift_top);CHKERRQ(ierr);
617     } else if (info->shiftnz) {
618       ierr = PetscInfo2(A,"number of shift_nz tries %D, shift_amount %G\n",sctx.nshift,sctx.shift_amount);CHKERRQ(ierr);
619     } else if (info->shiftinblocks){
620       ierr = PetscInfo2(A,"number of shift_inblocks applied %D, each shift_amount %G\n",sctx.nshift,info->shiftinblocks);CHKERRQ(ierr);
621     }
622   }
623   PetscFunctionReturn(0);
624 }
625 
626 #undef __FUNCT__
627 #define __FUNCT__ "MatLUFactorNumeric_SeqAIJ_inplace"
628 PetscErrorCode MatLUFactorNumeric_SeqAIJ_inplace(Mat B,Mat A,const MatFactorInfo *info)
629 {
630   Mat             C=B;
631   Mat_SeqAIJ      *a=(Mat_SeqAIJ*)A->data,*b=(Mat_SeqAIJ *)C->data;
632   IS              isrow = b->row,isicol = b->icol;
633   PetscErrorCode  ierr;
634   const PetscInt   *r,*ic,*ics;
635   PetscInt        nz,row,i,j,n=A->rmap->n,diag;
636   const PetscInt  *ai=a->i,*aj=a->j,*bi=b->i,*bj=b->j;
637   const PetscInt  *ajtmp,*bjtmp,*diag_offset = b->diag,*pj;
638   MatScalar       *pv,*rtmp,*pc,multiplier,d;
639   const MatScalar *v,*aa=a->a;
640   PetscReal       rs=0.0;
641   FactorShiftCtx  sctx;
642   PetscInt        newshift,*ddiag;
643 
644   PetscFunctionBegin;
645   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
646   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
647   ierr = PetscMalloc((n+1)*sizeof(MatScalar),&rtmp);CHKERRQ(ierr);
648   ics  = ic;
649 
650   /* initialize shift context sctx */
651   sctx.nshift         = 0;
652   sctx.nshift_max     = 0;
653   sctx.shift_top      = 0.0;
654   sctx.shift_lo       = 0.0;
655   sctx.shift_hi       = 0.0;
656   sctx.shift_fraction = 0.0;
657   sctx.shift_amount   = 0.0;
658 
659   /* if both shift schemes are chosen by user, only use info->shiftpd */
660   if (info->shiftpd) { /* set sctx.shift_top=max{rs} */
661     ddiag          = a->diag;
662     sctx.shift_top = info->zeropivot;
663     for (i=0; i<n; i++) {
664       /* calculate sum(|aij|)-RealPart(aii), amt of shift needed for this row */
665       d  = (aa)[ddiag[i]];
666       rs = -PetscAbsScalar(d) - PetscRealPart(d);
667       v  = aa+ai[i];
668       nz = ai[i+1] - ai[i];
669       for (j=0; j<nz; j++)
670 	rs += PetscAbsScalar(v[j]);
671       if (rs>sctx.shift_top) sctx.shift_top = rs;
672     }
673     sctx.shift_top   *= 1.1;
674     sctx.nshift_max   = 5;
675     sctx.shift_lo     = 0.;
676     sctx.shift_hi     = 1.;
677   }
678 
679   do {
680     sctx.useshift = PETSC_FALSE;
681     for (i=0; i<n; i++){
682       nz    = bi[i+1] - bi[i];
683       bjtmp = bj + bi[i];
684       for  (j=0; j<nz; j++) rtmp[bjtmp[j]] = 0.0;
685 
686       /* load in initial (unfactored row) */
687       nz    = ai[r[i]+1] - ai[r[i]];
688       ajtmp = aj + ai[r[i]];
689       v     = aa + ai[r[i]];
690       for (j=0; j<nz; j++) {
691         rtmp[ics[ajtmp[j]]] = v[j];
692       }
693       rtmp[ics[r[i]]] += sctx.shift_amount; /* shift the diagonal of the matrix */
694       /* if (sctx.shift_amount > 0.0) printf("row %d, shift %g\n",i,sctx.shift_amount); */
695 
696       row = *bjtmp++;
697       while  (row < i) {
698         pc = rtmp + row;
699         if (*pc != 0.0) {
700           pv         = b->a + diag_offset[row];
701           pj         = b->j + diag_offset[row] + 1;
702           multiplier = *pc / *pv++;
703           *pc        = multiplier;
704           nz         = bi[row+1] - diag_offset[row] - 1;
705           for (j=0; j<nz; j++) rtmp[pj[j]] -= multiplier * pv[j];
706           ierr = PetscLogFlops(2.0*nz);CHKERRQ(ierr);
707         }
708         row = *bjtmp++;
709       }
710       /* finished row so stick it into b->a */
711       pv   = b->a + bi[i] ;
712       pj   = b->j + bi[i] ;
713       nz   = bi[i+1] - bi[i];
714       diag = diag_offset[i] - bi[i];
715       rs   = 0.0;
716       for (j=0; j<nz; j++) {
717         pv[j] = rtmp[pj[j]];
718         rs   += PetscAbsScalar(pv[j]);
719       }
720       rs   -= PetscAbsScalar(pv[diag]);
721 
722       /* 9/13/02 Victor Eijkhout suggested scaling zeropivot by rs for matrices with funny scalings */
723       sctx.rs  = rs;
724       sctx.pv  = pv[diag];
725       ierr = MatLUCheckShift_inline(info,sctx,i,newshift);CHKERRQ(ierr);
726       if (newshift == 1) break;
727     }
728 
729     if (info->shiftpd && !sctx.useshift && sctx.shift_fraction>0 && sctx.nshift<sctx.nshift_max) {
730       /*
731        * if no shift in this attempt & shifting & started shifting & can refine,
732        * then try lower shift
733        */
734       sctx.shift_hi       = sctx.shift_fraction;
735       sctx.shift_fraction = (sctx.shift_hi+sctx.shift_lo)/2.;
736       sctx.shift_amount   = sctx.shift_fraction * sctx.shift_top;
737       sctx.useshift        = PETSC_TRUE;
738       sctx.nshift++;
739     }
740   } while (sctx.useshift);
741 
742   /* invert diagonal entries for simplier triangular solves */
743   for (i=0; i<n; i++) {
744     b->a[diag_offset[i]] = 1.0/b->a[diag_offset[i]];
745   }
746   ierr = PetscFree(rtmp);CHKERRQ(ierr);
747   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
748   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
749   if (b->inode.use) {
750     C->ops->solve   = MatSolve_SeqAIJ_Inode_inplace;
751   } else {
752     PetscTruth row_identity, col_identity;
753     ierr = ISIdentity(isrow,&row_identity);CHKERRQ(ierr);
754     ierr = ISIdentity(isicol,&col_identity);CHKERRQ(ierr);
755     if (row_identity && col_identity) {
756       C->ops->solve   = MatSolve_SeqAIJ_NaturalOrdering_inplace;
757     } else {
758       C->ops->solve   = MatSolve_SeqAIJ_inplace;
759     }
760   }
761   C->ops->solveadd           = MatSolveAdd_SeqAIJ_inplace;
762   C->ops->solvetranspose     = MatSolveTranspose_SeqAIJ_inplace;
763   C->ops->solvetransposeadd  = MatSolveTransposeAdd_SeqAIJ_inplace;
764   C->ops->matsolve           = MatMatSolve_SeqAIJ_inplace;
765   C->assembled    = PETSC_TRUE;
766   C->preallocated = PETSC_TRUE;
767   ierr = PetscLogFlops(C->cmap->n);CHKERRQ(ierr);
768   if (sctx.nshift){
769      if (info->shiftpd) {
770       ierr = PetscInfo4(A,"number of shift_pd tries %D, shift_amount %G, diagonal shifted up by %e fraction top_value %e\n",sctx.nshift,sctx.shift_amount,sctx.shift_fraction,sctx.shift_top);CHKERRQ(ierr);
771     } else if (info->shiftnz) {
772       ierr = PetscInfo2(A,"number of shift_nz tries %D, shift_amount %G\n",sctx.nshift,sctx.shift_amount);CHKERRQ(ierr);
773     }
774   }
775   PetscFunctionReturn(0);
776 }
777 
778 /*
779    This routine implements inplace ILU(0) with row or/and column permutations.
780    Input:
781      A - original matrix
782    Output;
783      A - a->i (rowptr) is same as original rowptr, but factored i-the row is stored in rowperm[i]
784          a->j (col index) is permuted by the inverse of colperm, then sorted
785          a->a reordered accordingly with a->j
786          a->diag (ptr to diagonal elements) is updated.
787 */
788 #undef __FUNCT__
789 #define __FUNCT__ "MatLUFactorNumeric_SeqAIJ_InplaceWithPerm"
790 PetscErrorCode MatLUFactorNumeric_SeqAIJ_InplaceWithPerm(Mat B,Mat A,const MatFactorInfo *info)
791 {
792   Mat_SeqAIJ     *a=(Mat_SeqAIJ*)A->data;
793   IS             isrow = a->row,isicol = a->icol;
794   PetscErrorCode ierr;
795   const PetscInt *r,*ic,*ics;
796   PetscInt       i,j,n=A->rmap->n,*ai=a->i,*aj=a->j;
797   PetscInt       *ajtmp,nz,row;
798   PetscInt       *diag = a->diag,nbdiag,*pj;
799   PetscScalar    *rtmp,*pc,multiplier,d;
800   MatScalar      *v,*pv;
801   PetscReal      rs;
802   FactorShiftCtx sctx;
803   PetscInt       newshift;
804 
805   PetscFunctionBegin;
806   if (A != B) SETERRQ(PETSC_ERR_ARG_INCOMP,"input and output matrix must have same address");
807   ierr  = ISGetIndices(isrow,&r);CHKERRQ(ierr);
808   ierr  = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
809   ierr  = PetscMalloc((n+1)*sizeof(PetscScalar),&rtmp);CHKERRQ(ierr);
810   ierr  = PetscMemzero(rtmp,(n+1)*sizeof(PetscScalar));CHKERRQ(ierr);
811   ics = ic;
812 
813   sctx.shift_top      = 0.;
814   sctx.nshift_max     = 0;
815   sctx.shift_lo       = 0.;
816   sctx.shift_hi       = 0.;
817   sctx.shift_fraction = 0.;
818 
819   /* if both shift schemes are chosen by user, only use info->shiftpd */
820   if (info->shiftpd) { /* set sctx.shift_top=max{rs} */
821     sctx.shift_top = 0.;
822     for (i=0; i<n; i++) {
823       /* calculate sum(|aij|)-RealPart(aii), amt of shift needed for this row */
824       d  = (a->a)[diag[i]];
825       rs = -PetscAbsScalar(d) - PetscRealPart(d);
826       v  = a->a+ai[i];
827       nz = ai[i+1] - ai[i];
828       for (j=0; j<nz; j++)
829 	rs += PetscAbsScalar(v[j]);
830       if (rs>sctx.shift_top) sctx.shift_top = rs;
831     }
832     if (sctx.shift_top < info->zeropivot) sctx.shift_top = info->zeropivot;
833     sctx.shift_top    *= 1.1;
834     sctx.nshift_max   = 5;
835     sctx.shift_lo     = 0.;
836     sctx.shift_hi     = 1.;
837   }
838 
839   sctx.shift_amount = 0.;
840   sctx.nshift       = 0;
841   do {
842     sctx.useshift = PETSC_FALSE;
843     for (i=0; i<n; i++){
844       /* load in initial unfactored row */
845       nz    = ai[r[i]+1] - ai[r[i]];
846       ajtmp = aj + ai[r[i]];
847       v     = a->a + ai[r[i]];
848       /* sort permuted ajtmp and values v accordingly */
849       for (j=0; j<nz; j++) ajtmp[j] = ics[ajtmp[j]];
850       ierr = PetscSortIntWithScalarArray(nz,ajtmp,v);CHKERRQ(ierr);
851 
852       diag[r[i]] = ai[r[i]];
853       for (j=0; j<nz; j++) {
854         rtmp[ajtmp[j]] = v[j];
855         if (ajtmp[j] < i) diag[r[i]]++; /* update a->diag */
856       }
857       rtmp[r[i]] += sctx.shift_amount; /* shift the diagonal of the matrix */
858 
859       row = *ajtmp++;
860       while  (row < i) {
861         pc = rtmp + row;
862         if (*pc != 0.0) {
863           pv         = a->a + diag[r[row]];
864           pj         = aj + diag[r[row]] + 1;
865 
866           multiplier = *pc / *pv++;
867           *pc        = multiplier;
868           nz         = ai[r[row]+1] - diag[r[row]] - 1;
869           for (j=0; j<nz; j++) rtmp[pj[j]] -= multiplier * pv[j];
870           ierr = PetscLogFlops(2.0*nz);CHKERRQ(ierr);
871         }
872         row = *ajtmp++;
873       }
874       /* finished row so overwrite it onto a->a */
875       pv   = a->a + ai[r[i]] ;
876       pj   = aj + ai[r[i]] ;
877       nz   = ai[r[i]+1] - ai[r[i]];
878       nbdiag = diag[r[i]] - ai[r[i]]; /* num of entries before the diagonal */
879 
880       rs   = 0.0;
881       for (j=0; j<nz; j++) {
882         pv[j] = rtmp[pj[j]];
883         if (j != nbdiag) rs += PetscAbsScalar(pv[j]);
884       }
885 
886       /* 9/13/02 Victor Eijkhout suggested scaling zeropivot by rs for matrices with funny scalings */
887       sctx.rs  = rs;
888       sctx.pv  = pv[nbdiag];
889       ierr = MatLUCheckShift_inline(info,sctx,i,newshift);CHKERRQ(ierr);
890       if (newshift == 1) break;
891     }
892 
893     if (info->shiftpd && !sctx.useshift && sctx.shift_fraction>0 && sctx.nshift<sctx.nshift_max) {
894       /*
895        * if no shift in this attempt & shifting & started shifting & can refine,
896        * then try lower shift
897        */
898       sctx.shift_hi        = sctx.shift_fraction;
899       sctx.shift_fraction = (sctx.shift_hi+sctx.shift_lo)/2.;
900       sctx.shift_amount    = sctx.shift_fraction * sctx.shift_top;
901       sctx.useshift         = PETSC_TRUE;
902       sctx.nshift++;
903     }
904   } while (sctx.useshift);
905 
906   /* invert diagonal entries for simplier triangular solves */
907   for (i=0; i<n; i++) {
908     a->a[diag[r[i]]] = 1.0/a->a[diag[r[i]]];
909   }
910 
911   ierr = PetscFree(rtmp);CHKERRQ(ierr);
912   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
913   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
914   A->ops->solve             = MatSolve_SeqAIJ_InplaceWithPerm;
915   A->ops->solveadd          = MatSolveAdd_SeqAIJ_inplace;
916   A->ops->solvetranspose    = MatSolveTranspose_SeqAIJ_inplace;
917   A->ops->solvetransposeadd = MatSolveTransposeAdd_SeqAIJ_inplace;
918   A->assembled = PETSC_TRUE;
919   A->preallocated = PETSC_TRUE;
920   ierr = PetscLogFlops(A->cmap->n);CHKERRQ(ierr);
921   if (sctx.nshift){
922     if (info->shiftpd) {
923       ierr = PetscInfo4(A,"number of shift_pd tries %D, shift_amount %G, diagonal shifted up by %e fraction top_value %e\n",sctx.nshift,sctx.shift_amount,sctx.shift_fraction,sctx.shift_top);CHKERRQ(ierr);
924     } else if (info->shiftnz) {
925       ierr = PetscInfo2(A,"number of shift_nz tries %D, shift_amount %G\n",sctx.nshift,sctx.shift_amount);CHKERRQ(ierr);
926     }
927   }
928   PetscFunctionReturn(0);
929 }
930 
931 /* ----------------------------------------------------------- */
932 #undef __FUNCT__
933 #define __FUNCT__ "MatLUFactor_SeqAIJ"
934 PetscErrorCode MatLUFactor_SeqAIJ(Mat A,IS row,IS col,const MatFactorInfo *info)
935 {
936   PetscErrorCode ierr;
937   Mat            C;
938 
939   PetscFunctionBegin;
940   ierr = MatGetFactor(A,MAT_SOLVER_PETSC,MAT_FACTOR_LU,&C);CHKERRQ(ierr);
941   ierr = MatLUFactorSymbolic(C,A,row,col,info);CHKERRQ(ierr);
942   ierr = MatLUFactorNumeric(C,A,info);CHKERRQ(ierr);
943   A->ops->solve            = C->ops->solve;
944   A->ops->solvetranspose   = C->ops->solvetranspose;
945   ierr = MatHeaderCopy(A,C);CHKERRQ(ierr);
946   ierr = PetscLogObjectParent(A,((Mat_SeqAIJ*)(A->data))->icol);CHKERRQ(ierr);
947   PetscFunctionReturn(0);
948 }
949 /* ----------------------------------------------------------- */
950 
951 
952 #undef __FUNCT__
953 #define __FUNCT__ "MatSolve_SeqAIJ_inplace"
954 PetscErrorCode MatSolve_SeqAIJ_inplace(Mat A,Vec bb,Vec xx)
955 {
956   Mat_SeqAIJ        *a = (Mat_SeqAIJ*)A->data;
957   IS                iscol = a->col,isrow = a->row;
958   PetscErrorCode    ierr;
959   PetscInt          i, n = A->rmap->n,*vi,*ai = a->i,*aj = a->j;
960   PetscInt          nz;
961   const PetscInt    *rout,*cout,*r,*c;
962   PetscScalar       *x,*tmp,*tmps,sum;
963   const PetscScalar *b;
964   const MatScalar   *aa = a->a,*v;
965 
966   PetscFunctionBegin;
967   if (!n) PetscFunctionReturn(0);
968 
969   ierr = VecGetArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
970   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
971   tmp  = a->solve_work;
972 
973   ierr = ISGetIndices(isrow,&rout);CHKERRQ(ierr); r = rout;
974   ierr = ISGetIndices(iscol,&cout);CHKERRQ(ierr); c = cout + (n-1);
975 
976   /* forward solve the lower triangular */
977   tmp[0] = b[*r++];
978   tmps   = tmp;
979   for (i=1; i<n; i++) {
980     v   = aa + ai[i] ;
981     vi  = aj + ai[i] ;
982     nz  = a->diag[i] - ai[i];
983     sum = b[*r++];
984     PetscSparseDenseMinusDot(sum,tmps,v,vi,nz);
985     tmp[i] = sum;
986   }
987 
988   /* backward solve the upper triangular */
989   for (i=n-1; i>=0; i--){
990     v   = aa + a->diag[i] + 1;
991     vi  = aj + a->diag[i] + 1;
992     nz  = ai[i+1] - a->diag[i] - 1;
993     sum = tmp[i];
994     PetscSparseDenseMinusDot(sum,tmps,v,vi,nz);
995     x[*c--] = tmp[i] = sum*aa[a->diag[i]];
996   }
997 
998   ierr = ISRestoreIndices(isrow,&rout);CHKERRQ(ierr);
999   ierr = ISRestoreIndices(iscol,&cout);CHKERRQ(ierr);
1000   ierr = VecRestoreArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1001   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
1002   ierr = PetscLogFlops(2.0*a->nz - A->cmap->n);CHKERRQ(ierr);
1003   PetscFunctionReturn(0);
1004 }
1005 
1006 #undef __FUNCT__
1007 #define __FUNCT__ "MatMatSolve_SeqAIJ_inplace"
1008 PetscErrorCode MatMatSolve_SeqAIJ_inplace(Mat A,Mat B,Mat X)
1009 {
1010   Mat_SeqAIJ      *a = (Mat_SeqAIJ*)A->data;
1011   IS              iscol = a->col,isrow = a->row;
1012   PetscErrorCode  ierr;
1013   PetscInt        i, n = A->rmap->n,*vi,*ai = a->i,*aj = a->j;
1014   PetscInt        nz,neq;
1015   const PetscInt  *rout,*cout,*r,*c;
1016   PetscScalar     *x,*b,*tmp,*tmps,sum;
1017   const MatScalar *aa = a->a,*v;
1018   PetscTruth      bisdense,xisdense;
1019 
1020   PetscFunctionBegin;
1021   if (!n) PetscFunctionReturn(0);
1022 
1023   ierr = PetscTypeCompare((PetscObject)B,MATSEQDENSE,&bisdense);CHKERRQ(ierr);
1024   if (!bisdense) SETERRQ(PETSC_ERR_ARG_INCOMP,"B matrix must be a SeqDense matrix");
1025   ierr = PetscTypeCompare((PetscObject)X,MATSEQDENSE,&xisdense);CHKERRQ(ierr);
1026   if (!xisdense) SETERRQ(PETSC_ERR_ARG_INCOMP,"X matrix must be a SeqDense matrix");
1027 
1028   ierr = MatGetArray(B,&b);CHKERRQ(ierr);
1029   ierr = MatGetArray(X,&x);CHKERRQ(ierr);
1030 
1031   tmp  = a->solve_work;
1032   ierr = ISGetIndices(isrow,&rout);CHKERRQ(ierr); r = rout;
1033   ierr = ISGetIndices(iscol,&cout);CHKERRQ(ierr); c = cout;
1034 
1035   for (neq=0; neq<B->cmap->n; neq++){
1036     /* forward solve the lower triangular */
1037     tmp[0] = b[r[0]];
1038     tmps   = tmp;
1039     for (i=1; i<n; i++) {
1040       v   = aa + ai[i] ;
1041       vi  = aj + ai[i] ;
1042       nz  = a->diag[i] - ai[i];
1043       sum = b[r[i]];
1044       PetscSparseDenseMinusDot(sum,tmps,v,vi,nz);
1045       tmp[i] = sum;
1046     }
1047     /* backward solve the upper triangular */
1048     for (i=n-1; i>=0; i--){
1049       v   = aa + a->diag[i] + 1;
1050       vi  = aj + a->diag[i] + 1;
1051       nz  = ai[i+1] - a->diag[i] - 1;
1052       sum = tmp[i];
1053       PetscSparseDenseMinusDot(sum,tmps,v,vi,nz);
1054       x[c[i]] = tmp[i] = sum*aa[a->diag[i]];
1055     }
1056 
1057     b += n;
1058     x += n;
1059   }
1060   ierr = ISRestoreIndices(isrow,&rout);CHKERRQ(ierr);
1061   ierr = ISRestoreIndices(iscol,&cout);CHKERRQ(ierr);
1062   ierr = MatRestoreArray(B,&b);CHKERRQ(ierr);
1063   ierr = MatRestoreArray(X,&x);CHKERRQ(ierr);
1064   ierr = PetscLogFlops(B->cmap->n*(2.0*a->nz - n));CHKERRQ(ierr);
1065   PetscFunctionReturn(0);
1066 }
1067 
1068 #undef __FUNCT__
1069 #define __FUNCT__ "MatMatSolve_SeqAIJ"
1070 PetscErrorCode MatMatSolve_SeqAIJ(Mat A,Mat B,Mat X)
1071 {
1072   Mat_SeqAIJ      *a = (Mat_SeqAIJ*)A->data;
1073   IS              iscol = a->col,isrow = a->row;
1074   PetscErrorCode  ierr;
1075   PetscInt        i, n = A->rmap->n,*vi,*ai = a->i,*aj = a->j,*adiag = a->diag;
1076   PetscInt        nz,neq;
1077   const PetscInt  *rout,*cout,*r,*c;
1078   PetscScalar     *x,*b,*tmp,sum;
1079   const MatScalar *aa = a->a,*v;
1080   PetscTruth      bisdense,xisdense;
1081 
1082   PetscFunctionBegin;
1083   if (!n) PetscFunctionReturn(0);
1084 
1085   ierr = PetscTypeCompare((PetscObject)B,MATSEQDENSE,&bisdense);CHKERRQ(ierr);
1086   if (!bisdense) SETERRQ(PETSC_ERR_ARG_INCOMP,"B matrix must be a SeqDense matrix");
1087   ierr = PetscTypeCompare((PetscObject)X,MATSEQDENSE,&xisdense);CHKERRQ(ierr);
1088   if (!xisdense) SETERRQ(PETSC_ERR_ARG_INCOMP,"X matrix must be a SeqDense matrix");
1089 
1090   ierr = MatGetArray(B,&b);CHKERRQ(ierr);
1091   ierr = MatGetArray(X,&x);CHKERRQ(ierr);
1092 
1093   tmp  = a->solve_work;
1094   ierr = ISGetIndices(isrow,&rout);CHKERRQ(ierr); r = rout;
1095   ierr = ISGetIndices(iscol,&cout);CHKERRQ(ierr); c = cout;
1096 
1097   for (neq=0; neq<B->cmap->n; neq++){
1098     /* forward solve the lower triangular */
1099     tmp[0] = b[r[0]];
1100     v      = aa;
1101     vi     = aj;
1102     for (i=1; i<n; i++) {
1103       nz  = ai[i+1] - ai[i];
1104       sum = b[r[i]];
1105       PetscSparseDenseMinusDot(sum,tmp,v,vi,nz);
1106       tmp[i] = sum;
1107       v += nz; vi += nz;
1108     }
1109 
1110     /* backward solve the upper triangular */
1111     for (i=n-1; i>=0; i--){
1112       v   = aa + adiag[i+1]+1;
1113       vi  = aj + adiag[i+1]+1;
1114       nz  = adiag[i]-adiag[i+1]-1;
1115       sum = tmp[i];
1116       PetscSparseDenseMinusDot(sum,tmp,v,vi,nz);
1117       x[c[i]] = tmp[i] = sum*v[nz]; /* v[nz] = aa[adiag[i]] */
1118     }
1119 
1120     b += n;
1121     x += n;
1122   }
1123   ierr = ISRestoreIndices(isrow,&rout);CHKERRQ(ierr);
1124   ierr = ISRestoreIndices(iscol,&cout);CHKERRQ(ierr);
1125   ierr = MatRestoreArray(B,&b);CHKERRQ(ierr);
1126   ierr = MatRestoreArray(X,&x);CHKERRQ(ierr);
1127   ierr = PetscLogFlops(B->cmap->n*(2.0*a->nz - n));CHKERRQ(ierr);
1128   PetscFunctionReturn(0);
1129 }
1130 
1131 #undef __FUNCT__
1132 #define __FUNCT__ "MatSolve_SeqAIJ_InplaceWithPerm"
1133 PetscErrorCode MatSolve_SeqAIJ_InplaceWithPerm(Mat A,Vec bb,Vec xx)
1134 {
1135   Mat_SeqAIJ      *a = (Mat_SeqAIJ*)A->data;
1136   IS              iscol = a->col,isrow = a->row;
1137   PetscErrorCode  ierr;
1138   const PetscInt  *r,*c,*rout,*cout;
1139   PetscInt        i, n = A->rmap->n,*vi,*ai = a->i,*aj = a->j;
1140   PetscInt        nz,row;
1141   PetscScalar     *x,*b,*tmp,*tmps,sum;
1142   const MatScalar *aa = a->a,*v;
1143 
1144   PetscFunctionBegin;
1145   if (!n) PetscFunctionReturn(0);
1146 
1147   ierr = VecGetArray(bb,&b);CHKERRQ(ierr);
1148   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
1149   tmp  = a->solve_work;
1150 
1151   ierr = ISGetIndices(isrow,&rout);CHKERRQ(ierr); r = rout;
1152   ierr = ISGetIndices(iscol,&cout);CHKERRQ(ierr); c = cout + (n-1);
1153 
1154   /* forward solve the lower triangular */
1155   tmp[0] = b[*r++];
1156   tmps   = tmp;
1157   for (row=1; row<n; row++) {
1158     i   = rout[row]; /* permuted row */
1159     v   = aa + ai[i] ;
1160     vi  = aj + ai[i] ;
1161     nz  = a->diag[i] - ai[i];
1162     sum = b[*r++];
1163     PetscSparseDenseMinusDot(sum,tmps,v,vi,nz);
1164     tmp[row] = sum;
1165   }
1166 
1167   /* backward solve the upper triangular */
1168   for (row=n-1; row>=0; row--){
1169     i   = rout[row]; /* permuted row */
1170     v   = aa + a->diag[i] + 1;
1171     vi  = aj + a->diag[i] + 1;
1172     nz  = ai[i+1] - a->diag[i] - 1;
1173     sum = tmp[row];
1174     PetscSparseDenseMinusDot(sum,tmps,v,vi,nz);
1175     x[*c--] = tmp[row] = sum*aa[a->diag[i]];
1176   }
1177 
1178   ierr = ISRestoreIndices(isrow,&rout);CHKERRQ(ierr);
1179   ierr = ISRestoreIndices(iscol,&cout);CHKERRQ(ierr);
1180   ierr = VecRestoreArray(bb,&b);CHKERRQ(ierr);
1181   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
1182   ierr = PetscLogFlops(2.0*a->nz - A->cmap->n);CHKERRQ(ierr);
1183   PetscFunctionReturn(0);
1184 }
1185 
1186 /* ----------------------------------------------------------- */
1187 #include "../src/mat/impls/aij/seq/ftn-kernels/fsolve.h"
1188 #undef __FUNCT__
1189 #define __FUNCT__ "MatSolve_SeqAIJ_NaturalOrdering_inplace"
1190 PetscErrorCode MatSolve_SeqAIJ_NaturalOrdering_inplace(Mat A,Vec bb,Vec xx)
1191 {
1192   Mat_SeqAIJ        *a = (Mat_SeqAIJ*)A->data;
1193   PetscErrorCode    ierr;
1194   PetscInt          n = A->rmap->n;
1195   const PetscInt    *ai = a->i,*aj = a->j,*adiag = a->diag;
1196   PetscScalar       *x;
1197   const PetscScalar *b;
1198   const MatScalar   *aa = a->a;
1199 #if !defined(PETSC_USE_FORTRAN_KERNEL_SOLVEAIJ)
1200   PetscInt          adiag_i,i,nz,ai_i;
1201   const PetscInt    *vi;
1202   const MatScalar   *v;
1203   PetscScalar       sum;
1204 #endif
1205 
1206   PetscFunctionBegin;
1207   if (!n) PetscFunctionReturn(0);
1208 
1209   ierr = VecGetArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1210   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
1211 
1212 #if defined(PETSC_USE_FORTRAN_KERNEL_SOLVEAIJ)
1213   fortransolveaij_(&n,x,ai,aj,adiag,aa,b);
1214 #else
1215   /* forward solve the lower triangular */
1216   x[0] = b[0];
1217   for (i=1; i<n; i++) {
1218     ai_i = ai[i];
1219     v    = aa + ai_i;
1220     vi   = aj + ai_i;
1221     nz   = adiag[i] - ai_i;
1222     sum  = b[i];
1223     PetscSparseDenseMinusDot(sum,x,v,vi,nz);
1224     x[i] = sum;
1225   }
1226 
1227   /* backward solve the upper triangular */
1228   for (i=n-1; i>=0; i--){
1229     adiag_i = adiag[i];
1230     v       = aa + adiag_i + 1;
1231     vi      = aj + adiag_i + 1;
1232     nz      = ai[i+1] - adiag_i - 1;
1233     sum     = x[i];
1234     PetscSparseDenseMinusDot(sum,x,v,vi,nz);
1235     x[i]    = sum*aa[adiag_i];
1236   }
1237 #endif
1238   ierr = PetscLogFlops(2.0*a->nz - A->cmap->n);CHKERRQ(ierr);
1239   ierr = VecRestoreArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1240   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
1241   PetscFunctionReturn(0);
1242 }
1243 
1244 #undef __FUNCT__
1245 #define __FUNCT__ "MatSolveAdd_SeqAIJ_inplace"
1246 PetscErrorCode MatSolveAdd_SeqAIJ_inplace(Mat A,Vec bb,Vec yy,Vec xx)
1247 {
1248   Mat_SeqAIJ        *a = (Mat_SeqAIJ*)A->data;
1249   IS                iscol = a->col,isrow = a->row;
1250   PetscErrorCode    ierr;
1251   PetscInt          i, n = A->rmap->n,j;
1252   PetscInt          nz;
1253   const PetscInt    *rout,*cout,*r,*c,*vi,*ai = a->i,*aj = a->j;
1254   PetscScalar       *x,*tmp,sum;
1255   const PetscScalar *b;
1256   const MatScalar   *aa = a->a,*v;
1257 
1258   PetscFunctionBegin;
1259   if (yy != xx) {ierr = VecCopy(yy,xx);CHKERRQ(ierr);}
1260 
1261   ierr = VecGetArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1262   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
1263   tmp  = a->solve_work;
1264 
1265   ierr = ISGetIndices(isrow,&rout);CHKERRQ(ierr); r = rout;
1266   ierr = ISGetIndices(iscol,&cout);CHKERRQ(ierr); c = cout + (n-1);
1267 
1268   /* forward solve the lower triangular */
1269   tmp[0] = b[*r++];
1270   for (i=1; i<n; i++) {
1271     v   = aa + ai[i] ;
1272     vi  = aj + ai[i] ;
1273     nz  = a->diag[i] - ai[i];
1274     sum = b[*r++];
1275     for (j=0; j<nz; j++) sum -= v[j]*tmp[vi[j]];
1276     tmp[i] = sum;
1277   }
1278 
1279   /* backward solve the upper triangular */
1280   for (i=n-1; i>=0; i--){
1281     v   = aa + a->diag[i] + 1;
1282     vi  = aj + a->diag[i] + 1;
1283     nz  = ai[i+1] - a->diag[i] - 1;
1284     sum = tmp[i];
1285     for (j=0; j<nz; j++) sum -= v[j]*tmp[vi[j]];
1286     tmp[i] = sum*aa[a->diag[i]];
1287     x[*c--] += tmp[i];
1288   }
1289 
1290   ierr = ISRestoreIndices(isrow,&rout);CHKERRQ(ierr);
1291   ierr = ISRestoreIndices(iscol,&cout);CHKERRQ(ierr);
1292   ierr = VecRestoreArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1293   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
1294   ierr = PetscLogFlops(2.0*a->nz);CHKERRQ(ierr);
1295 
1296   PetscFunctionReturn(0);
1297 }
1298 
1299 #undef __FUNCT__
1300 #define __FUNCT__ "MatSolveAdd_SeqAIJ"
1301 PetscErrorCode MatSolveAdd_SeqAIJ(Mat A,Vec bb,Vec yy,Vec xx)
1302 {
1303   Mat_SeqAIJ        *a = (Mat_SeqAIJ*)A->data;
1304   IS                iscol = a->col,isrow = a->row;
1305   PetscErrorCode    ierr;
1306   PetscInt          i, n = A->rmap->n,j;
1307   PetscInt          nz;
1308   const PetscInt    *rout,*cout,*r,*c,*vi,*ai = a->i,*aj = a->j,*adiag = a->diag;
1309   PetscScalar       *x,*tmp,sum;
1310   const PetscScalar *b;
1311   const MatScalar   *aa = a->a,*v;
1312 
1313   PetscFunctionBegin;
1314   if (yy != xx) {ierr = VecCopy(yy,xx);CHKERRQ(ierr);}
1315 
1316   ierr = VecGetArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1317   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
1318   tmp  = a->solve_work;
1319 
1320   ierr = ISGetIndices(isrow,&rout);CHKERRQ(ierr); r = rout;
1321   ierr = ISGetIndices(iscol,&cout);CHKERRQ(ierr); c = cout;
1322 
1323   /* forward solve the lower triangular */
1324   tmp[0] = b[r[0]];
1325   v      = aa;
1326   vi     = aj;
1327   for (i=1; i<n; i++) {
1328     nz  = ai[i+1] - ai[i];
1329     sum = b[r[i]];
1330     for (j=0; j<nz; j++) sum -= v[j]*tmp[vi[j]];
1331     tmp[i] = sum;
1332     v += nz; vi += nz;
1333   }
1334 
1335   /* backward solve the upper triangular */
1336   v  = aa + adiag[n-1];
1337   vi = aj + adiag[n-1];
1338   for (i=n-1; i>=0; i--){
1339     nz  = adiag[i] - adiag[i+1] - 1;
1340     sum = tmp[i];
1341     for (j=0; j<nz; j++) sum -= v[j]*tmp[vi[j]];
1342     tmp[i] = sum*v[nz];
1343     x[c[i]] += tmp[i];
1344     v += nz+1; vi += nz+1;
1345   }
1346 
1347   ierr = ISRestoreIndices(isrow,&rout);CHKERRQ(ierr);
1348   ierr = ISRestoreIndices(iscol,&cout);CHKERRQ(ierr);
1349   ierr = VecRestoreArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1350   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
1351   ierr = PetscLogFlops(2.0*a->nz);CHKERRQ(ierr);
1352 
1353   PetscFunctionReturn(0);
1354 }
1355 
1356 #undef __FUNCT__
1357 #define __FUNCT__ "MatSolveTranspose_SeqAIJ_inplace"
1358 PetscErrorCode MatSolveTranspose_SeqAIJ_inplace(Mat A,Vec bb,Vec xx)
1359 {
1360   Mat_SeqAIJ        *a = (Mat_SeqAIJ*)A->data;
1361   IS                iscol = a->col,isrow = a->row;
1362   PetscErrorCode    ierr;
1363   const PetscInt    *rout,*cout,*r,*c,*diag = a->diag,*ai = a->i,*aj = a->j,*vi;
1364   PetscInt          i,n = A->rmap->n,j;
1365   PetscInt          nz;
1366   PetscScalar       *x,*tmp,s1;
1367   const MatScalar   *aa = a->a,*v;
1368   const PetscScalar *b;
1369 
1370   PetscFunctionBegin;
1371   ierr = VecGetArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1372   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
1373   tmp  = a->solve_work;
1374 
1375   ierr = ISGetIndices(isrow,&rout);CHKERRQ(ierr); r = rout;
1376   ierr = ISGetIndices(iscol,&cout);CHKERRQ(ierr); c = cout;
1377 
1378   /* copy the b into temp work space according to permutation */
1379   for (i=0; i<n; i++) tmp[i] = b[c[i]];
1380 
1381   /* forward solve the U^T */
1382   for (i=0; i<n; i++) {
1383     v   = aa + diag[i] ;
1384     vi  = aj + diag[i] + 1;
1385     nz  = ai[i+1] - diag[i] - 1;
1386     s1  = tmp[i];
1387     s1 *= (*v++);  /* multiply by inverse of diagonal entry */
1388     for (j=0; j<nz; j++) tmp[vi[j]] -= s1*v[j];
1389     tmp[i] = s1;
1390   }
1391 
1392   /* backward solve the L^T */
1393   for (i=n-1; i>=0; i--){
1394     v   = aa + diag[i] - 1 ;
1395     vi  = aj + diag[i] - 1 ;
1396     nz  = diag[i] - ai[i];
1397     s1  = tmp[i];
1398     for (j=0; j>-nz; j--) tmp[vi[j]] -= s1*v[j];
1399   }
1400 
1401   /* copy tmp into x according to permutation */
1402   for (i=0; i<n; i++) x[r[i]] = tmp[i];
1403 
1404   ierr = ISRestoreIndices(isrow,&rout);CHKERRQ(ierr);
1405   ierr = ISRestoreIndices(iscol,&cout);CHKERRQ(ierr);
1406   ierr = VecRestoreArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1407   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
1408 
1409   ierr = PetscLogFlops(2.0*a->nz-A->cmap->n);CHKERRQ(ierr);
1410   PetscFunctionReturn(0);
1411 }
1412 
1413 #undef __FUNCT__
1414 #define __FUNCT__ "MatSolveTranspose_SeqAIJ"
1415 PetscErrorCode MatSolveTranspose_SeqAIJ(Mat A,Vec bb,Vec xx)
1416 {
1417   Mat_SeqAIJ        *a = (Mat_SeqAIJ*)A->data;
1418   IS                iscol = a->col,isrow = a->row;
1419   PetscErrorCode    ierr;
1420   const PetscInt    *rout,*cout,*r,*c,*adiag = a->diag,*ai = a->i,*aj = a->j,*vi;
1421   PetscInt          i,n = A->rmap->n,j;
1422   PetscInt          nz;
1423   PetscScalar       *x,*tmp,s1;
1424   const MatScalar   *aa = a->a,*v;
1425   const PetscScalar *b;
1426 
1427   PetscFunctionBegin;
1428   ierr = VecGetArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1429   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
1430   tmp  = a->solve_work;
1431 
1432   ierr = ISGetIndices(isrow,&rout);CHKERRQ(ierr); r = rout;
1433   ierr = ISGetIndices(iscol,&cout);CHKERRQ(ierr); c = cout;
1434 
1435   /* copy the b into temp work space according to permutation */
1436   for (i=0; i<n; i++) tmp[i] = b[c[i]];
1437 
1438   /* forward solve the U^T */
1439   for (i=0; i<n; i++) {
1440     v   = aa + adiag[i+1] + 1;
1441     vi  = aj + adiag[i+1] + 1;
1442     nz  = adiag[i] - adiag[i+1] - 1;
1443     s1  = tmp[i];
1444     s1 *= v[nz];  /* multiply by inverse of diagonal entry */
1445     for (j=0; j<nz; j++) tmp[vi[j]] -= s1*v[j];
1446     tmp[i] = s1;
1447   }
1448 
1449   /* backward solve the L^T */
1450   for (i=n-1; i>=0; i--){
1451     v   = aa + ai[i];
1452     vi  = aj + ai[i];
1453     nz  = ai[i+1] - ai[i];
1454     s1  = tmp[i];
1455     for (j=0; j<nz; j++) tmp[vi[j]] -= s1*v[j];
1456   }
1457 
1458   /* copy tmp into x according to permutation */
1459   for (i=0; i<n; i++) x[r[i]] = tmp[i];
1460 
1461   ierr = ISRestoreIndices(isrow,&rout);CHKERRQ(ierr);
1462   ierr = ISRestoreIndices(iscol,&cout);CHKERRQ(ierr);
1463   ierr = VecRestoreArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1464   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
1465 
1466   ierr = PetscLogFlops(2.0*a->nz-A->cmap->n);CHKERRQ(ierr);
1467   PetscFunctionReturn(0);
1468 }
1469 
1470 #undef __FUNCT__
1471 #define __FUNCT__ "MatSolveTransposeAdd_SeqAIJ_inplace"
1472 PetscErrorCode MatSolveTransposeAdd_SeqAIJ_inplace(Mat A,Vec bb,Vec zz,Vec xx)
1473 {
1474   Mat_SeqAIJ        *a = (Mat_SeqAIJ*)A->data;
1475   IS                iscol = a->col,isrow = a->row;
1476   PetscErrorCode    ierr;
1477   const PetscInt    *rout,*cout,*r,*c,*diag = a->diag,*ai = a->i,*aj = a->j,*vi;
1478   PetscInt          i,n = A->rmap->n,j;
1479   PetscInt          nz;
1480   PetscScalar       *x,*tmp,s1;
1481   const MatScalar   *aa = a->a,*v;
1482   const PetscScalar *b;
1483 
1484   PetscFunctionBegin;
1485   if (zz != xx) {ierr = VecCopy(zz,xx);CHKERRQ(ierr);}
1486   ierr = VecGetArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1487   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
1488   tmp  = a->solve_work;
1489 
1490   ierr = ISGetIndices(isrow,&rout);CHKERRQ(ierr); r = rout;
1491   ierr = ISGetIndices(iscol,&cout);CHKERRQ(ierr); c = cout;
1492 
1493   /* copy the b into temp work space according to permutation */
1494   for (i=0; i<n; i++) tmp[i] = b[c[i]];
1495 
1496   /* forward solve the U^T */
1497   for (i=0; i<n; i++) {
1498     v   = aa + diag[i] ;
1499     vi  = aj + diag[i] + 1;
1500     nz  = ai[i+1] - diag[i] - 1;
1501     s1  = tmp[i];
1502     s1 *= (*v++);  /* multiply by inverse of diagonal entry */
1503     for (j=0; j<nz; j++) tmp[vi[j]] -= s1*v[j];
1504     tmp[i] = s1;
1505   }
1506 
1507   /* backward solve the L^T */
1508   for (i=n-1; i>=0; i--){
1509     v   = aa + diag[i] - 1 ;
1510     vi  = aj + diag[i] - 1 ;
1511     nz  = diag[i] - ai[i];
1512     s1  = tmp[i];
1513     for (j=0; j>-nz; j--) tmp[vi[j]] -= s1*v[j];
1514   }
1515 
1516   /* copy tmp into x according to permutation */
1517   for (i=0; i<n; i++) x[r[i]] += tmp[i];
1518 
1519   ierr = ISRestoreIndices(isrow,&rout);CHKERRQ(ierr);
1520   ierr = ISRestoreIndices(iscol,&cout);CHKERRQ(ierr);
1521   ierr = VecRestoreArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1522   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
1523 
1524   ierr = PetscLogFlops(2.0*a->nz-A->cmap->n);CHKERRQ(ierr);
1525   PetscFunctionReturn(0);
1526 }
1527 
1528 #undef __FUNCT__
1529 #define __FUNCT__ "MatSolveTransposeAdd_SeqAIJ"
1530 PetscErrorCode MatSolveTransposeAdd_SeqAIJ(Mat A,Vec bb,Vec zz,Vec xx)
1531 {
1532   Mat_SeqAIJ        *a = (Mat_SeqAIJ*)A->data;
1533   IS                iscol = a->col,isrow = a->row;
1534   PetscErrorCode    ierr;
1535   const PetscInt    *rout,*cout,*r,*c,*adiag = a->diag,*ai = a->i,*aj = a->j,*vi;
1536   PetscInt          i,n = A->rmap->n,j;
1537   PetscInt          nz;
1538   PetscScalar       *x,*tmp,s1;
1539   const MatScalar   *aa = a->a,*v;
1540   const PetscScalar *b;
1541 
1542   PetscFunctionBegin;
1543   if (zz != xx) {ierr = VecCopy(zz,xx);CHKERRQ(ierr);}
1544   ierr = VecGetArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1545   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
1546   tmp  = a->solve_work;
1547 
1548   ierr = ISGetIndices(isrow,&rout);CHKERRQ(ierr); r = rout;
1549   ierr = ISGetIndices(iscol,&cout);CHKERRQ(ierr); c = cout;
1550 
1551   /* copy the b into temp work space according to permutation */
1552   for (i=0; i<n; i++) tmp[i] = b[c[i]];
1553 
1554   /* forward solve the U^T */
1555   for (i=0; i<n; i++) {
1556     v   = aa + adiag[i+1] + 1;
1557     vi  = aj + adiag[i+1] + 1;
1558     nz  = adiag[i] - adiag[i+1] - 1;
1559     s1  = tmp[i];
1560     s1 *= v[nz];  /* multiply by inverse of diagonal entry */
1561     for (j=0; j<nz; j++) tmp[vi[j]] -= s1*v[j];
1562     tmp[i] = s1;
1563   }
1564 
1565 
1566   /* backward solve the L^T */
1567   for (i=n-1; i>=0; i--){
1568     v   = aa + ai[i] ;
1569     vi  = aj + ai[i];
1570     nz  = ai[i+1] - ai[i];
1571     s1  = tmp[i];
1572     for (j=0; j<nz; j++) tmp[vi[j]] -= s1*v[j];
1573   }
1574 
1575   /* copy tmp into x according to permutation */
1576   for (i=0; i<n; i++) x[r[i]] += tmp[i];
1577 
1578   ierr = ISRestoreIndices(isrow,&rout);CHKERRQ(ierr);
1579   ierr = ISRestoreIndices(iscol,&cout);CHKERRQ(ierr);
1580   ierr = VecRestoreArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
1581   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
1582 
1583   ierr = PetscLogFlops(2.0*a->nz-A->cmap->n);CHKERRQ(ierr);
1584   PetscFunctionReturn(0);
1585 }
1586 
1587 /* ----------------------------------------------------------------*/
1588 
1589 EXTERN PetscErrorCode MatDuplicateNoCreate_SeqAIJ(Mat,Mat,MatDuplicateOption,PetscTruth);
1590 
1591 /*
1592    ilu() under revised new data structure.
1593    Factored arrays bj and ba are stored as
1594      L(0,:), L(1,:), ...,L(n-1,:),  U(n-1,:),...,U(i,:),U(i-1,:),...,U(0,:)
1595 
1596    bi=fact->i is an array of size n+1, in which
1597    bi+
1598      bi[i]:  points to 1st entry of L(i,:),i=0,...,n-1
1599      bi[n]:  points to L(n-1,n-1)+1
1600 
1601   bdiag=fact->diag is an array of size n+1,in which
1602      bdiag[i]: points to diagonal of U(i,:), i=0,...,n-1
1603      bdiag[n]: points to entry of U(n-1,0)-1
1604 
1605    U(i,:) contains bdiag[i] as its last entry, i.e.,
1606     U(i,:) = (u[i,i+1],...,u[i,n-1],diag[i])
1607 */
1608 #undef __FUNCT__
1609 #define __FUNCT__ "MatILUFactorSymbolic_SeqAIJ_ilu0"
1610 PetscErrorCode MatILUFactorSymbolic_SeqAIJ_ilu0(Mat fact,Mat A,IS isrow,IS iscol,const MatFactorInfo *info)
1611 {
1612 
1613   Mat_SeqAIJ         *a = (Mat_SeqAIJ*)A->data,*b;
1614   PetscErrorCode     ierr;
1615   const PetscInt     n=A->rmap->n,*ai=a->i,*aj,*adiag=a->diag;
1616   PetscInt           i,j,k=0,nz,*bi,*bj,*bdiag;
1617   PetscTruth         missing;
1618   IS                 isicol;
1619 
1620   PetscFunctionBegin;
1621   if (A->rmap->n != A->cmap->n) SETERRQ2(PETSC_ERR_ARG_WRONG,"Must be square matrix, rows %D columns %D",A->rmap->n,A->cmap->n);
1622   ierr = MatMissingDiagonal(A,&missing,&i);CHKERRQ(ierr);
1623   if (missing) SETERRQ1(PETSC_ERR_ARG_WRONGSTATE,"Matrix is missing diagonal entry %D",i);
1624   ierr = ISInvertPermutation(iscol,PETSC_DECIDE,&isicol);CHKERRQ(ierr);
1625 
1626   ierr = MatDuplicateNoCreate_SeqAIJ(fact,A,MAT_DO_NOT_COPY_VALUES,PETSC_FALSE);CHKERRQ(ierr);
1627   b    = (Mat_SeqAIJ*)(fact)->data;
1628 
1629   /* allocate matrix arrays for new data structure */
1630   ierr = PetscMalloc3(ai[n]+1,PetscScalar,&b->a,ai[n]+1,PetscInt,&b->j,n+1,PetscInt,&b->i);CHKERRQ(ierr);
1631   ierr = PetscLogObjectMemory(fact,ai[n]*(sizeof(PetscScalar)+sizeof(PetscInt))+(n+1)*sizeof(PetscInt));CHKERRQ(ierr);
1632   b->singlemalloc = PETSC_TRUE;
1633   if (!b->diag){
1634     ierr = PetscMalloc((n+1)*sizeof(PetscInt),&b->diag);CHKERRQ(ierr);
1635     ierr = PetscLogObjectMemory(fact,(n+1)*sizeof(PetscInt));CHKERRQ(ierr);
1636   }
1637   bdiag = b->diag;
1638 
1639   if (n > 0) {
1640     ierr = PetscMemzero(b->a,(ai[n])*sizeof(MatScalar));CHKERRQ(ierr);
1641   }
1642 
1643   /* set bi and bj with new data structure */
1644   bi = b->i;
1645   bj = b->j;
1646 
1647   /* L part */
1648   bi[0] = 0;
1649   for (i=0; i<n; i++){
1650     nz = adiag[i] - ai[i];
1651     bi[i+1] = bi[i] + nz;
1652     aj = a->j + ai[i];
1653     for (j=0; j<nz; j++){
1654       /*   *bj = aj[j]; bj++; */
1655       bj[k++] = aj[j];
1656     }
1657   }
1658 
1659   /* U part */
1660   bdiag[n] = bi[n]-1;
1661   for (i=n-1; i>=0; i--){
1662     nz = ai[i+1] - adiag[i] - 1;
1663     aj = a->j + adiag[i] + 1;
1664     for (j=0; j<nz; j++){
1665       /*      *bj = aj[j]; bj++; */
1666       bj[k++] = aj[j];
1667     }
1668     /* diag[i] */
1669     /*    *bj = i; bj++; */
1670     bj[k++] = i;
1671     bdiag[i] = bdiag[i+1] + nz + 1;
1672   }
1673 
1674   fact->factor                 = MAT_FACTOR_ILU;
1675   fact->info.factor_mallocs    = 0;
1676   fact->info.fill_ratio_given  = info->fill;
1677   fact->info.fill_ratio_needed = 1.0;
1678   fact->ops->lufactornumeric   = MatLUFactorNumeric_SeqAIJ;
1679 
1680   b       = (Mat_SeqAIJ*)(fact)->data;
1681   b->row  = isrow;
1682   b->col  = iscol;
1683   b->icol = isicol;
1684   ierr    = PetscMalloc((fact->rmap->n+1)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
1685   ierr    = PetscObjectReference((PetscObject)isrow);CHKERRQ(ierr);
1686   ierr    = PetscObjectReference((PetscObject)iscol);CHKERRQ(ierr);
1687   PetscFunctionReturn(0);
1688 }
1689 
1690 #undef __FUNCT__
1691 #define __FUNCT__ "MatILUFactorSymbolic_SeqAIJ"
1692 PetscErrorCode MatILUFactorSymbolic_SeqAIJ(Mat fact,Mat A,IS isrow,IS iscol,const MatFactorInfo *info)
1693 {
1694   Mat_SeqAIJ         *a = (Mat_SeqAIJ*)A->data,*b;
1695   IS                 isicol;
1696   PetscErrorCode     ierr;
1697   const PetscInt     *r,*ic;
1698   PetscInt           n=A->rmap->n,*ai=a->i,*aj=a->j;
1699   PetscInt           *bi,*cols,nnz,*cols_lvl;
1700   PetscInt           *bdiag,prow,fm,nzbd,reallocs=0,dcount=0;
1701   PetscInt           i,levels,diagonal_fill;
1702   PetscTruth         col_identity,row_identity;
1703   PetscReal          f;
1704   PetscInt           nlnk,*lnk,*lnk_lvl=PETSC_NULL;
1705   PetscBT            lnkbt;
1706   PetscInt           nzi,*bj,**bj_ptr,**bjlvl_ptr;
1707   PetscFreeSpaceList free_space=PETSC_NULL,current_space=PETSC_NULL;
1708   PetscFreeSpaceList free_space_lvl=PETSC_NULL,current_space_lvl=PETSC_NULL;
1709 
1710   PetscFunctionBegin;
1711   /* // Testing new data structure for MatSolve()
1712   PetscTruth         olddatastruct=PETSC_FALSE
1713   ierr = PetscOptionsGetTruth(PETSC_NULL,"-ilu_old",&olddatastruct,PETSC_NULL);CHKERRQ(ierr);
1714   if(olddatastruct){
1715     ierr = MatILUFactorSymbolic_SeqAIJ_inplace(fact,A,isrow,iscol,info);CHKERRQ(ierr);
1716     PetscFunctionReturn(0);
1717   }
1718   */
1719 
1720   levels = (PetscInt)info->levels;
1721   ierr   = ISIdentity(isrow,&row_identity);CHKERRQ(ierr);
1722   ierr   = ISIdentity(iscol,&col_identity);CHKERRQ(ierr);
1723 
1724   if (!levels && row_identity && col_identity) {
1725     /* special case: ilu(0) with natural ordering */
1726     ierr = MatILUFactorSymbolic_SeqAIJ_ilu0(fact,A,isrow,iscol,info);CHKERRQ(ierr);
1727     ierr = Mat_CheckInode_FactorLU(fact,PETSC_FALSE);CHKERRQ(ierr);
1728     PetscFunctionReturn(0);
1729   }
1730 
1731   if (A->rmap->n != A->cmap->n) SETERRQ2(PETSC_ERR_ARG_WRONG,"Must be square matrix, rows %D columns %D",A->rmap->n,A->cmap->n);
1732   ierr = ISInvertPermutation(iscol,PETSC_DECIDE,&isicol);CHKERRQ(ierr);
1733   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
1734   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
1735 
1736   /* get new row and diagonal pointers, must be allocated separately because they will be given to the Mat_SeqAIJ and freed separately */
1737   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bi);CHKERRQ(ierr);
1738   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bdiag);CHKERRQ(ierr);
1739   bi[0] = bdiag[0] = 0;
1740 
1741   ierr = PetscMalloc2(n,PetscInt*,&bj_ptr,n,PetscInt*,&bjlvl_ptr);CHKERRQ(ierr);
1742 
1743   /* create a linked list for storing column indices of the active row */
1744   nlnk = n + 1;
1745   ierr = PetscIncompleteLLCreate(n,n,nlnk,lnk,lnk_lvl,lnkbt);CHKERRQ(ierr);
1746 
1747   /* initial FreeSpace size is f*(ai[n]+1) */
1748   f             = info->fill;
1749   diagonal_fill = (PetscInt)info->diagonal_fill;
1750   ierr = PetscFreeSpaceGet((PetscInt)(f*(ai[n]+1)),&free_space);CHKERRQ(ierr);
1751   current_space = free_space;
1752   ierr = PetscFreeSpaceGet((PetscInt)(f*(ai[n]+1)),&free_space_lvl);CHKERRQ(ierr);
1753   current_space_lvl = free_space_lvl;
1754 
1755   for (i=0; i<n; i++) {
1756     nzi = 0;
1757     /* copy current row into linked list */
1758     nnz  = ai[r[i]+1] - ai[r[i]];
1759     if (!nnz) SETERRQ2(PETSC_ERR_MAT_LU_ZRPVT,"Empty row in matrix: row in original ordering %D in permuted ordering %D",r[i],i);
1760     cols = aj + ai[r[i]];
1761     lnk[i] = -1; /* marker to indicate if diagonal exists */
1762     ierr = PetscIncompleteLLInit(nnz,cols,n,ic,nlnk,lnk,lnk_lvl,lnkbt);CHKERRQ(ierr);
1763     nzi += nlnk;
1764 
1765     /* make sure diagonal entry is included */
1766     if (diagonal_fill && lnk[i] == -1) {
1767       fm = n;
1768       while (lnk[fm] < i) fm = lnk[fm];
1769       lnk[i]     = lnk[fm]; /* insert diagonal into linked list */
1770       lnk[fm]    = i;
1771       lnk_lvl[i] = 0;
1772       nzi++; dcount++;
1773     }
1774 
1775     /* add pivot rows into the active row */
1776     nzbd = 0;
1777     prow = lnk[n];
1778     while (prow < i) {
1779       nnz      = bdiag[prow];
1780       cols     = bj_ptr[prow] + nnz + 1;
1781       cols_lvl = bjlvl_ptr[prow] + nnz + 1;
1782       nnz      = bi[prow+1] - bi[prow] - nnz - 1;
1783       ierr = PetscILULLAddSorted(nnz,cols,levels,cols_lvl,prow,nlnk,lnk,lnk_lvl,lnkbt,prow);CHKERRQ(ierr);
1784       nzi += nlnk;
1785       prow = lnk[prow];
1786       nzbd++;
1787     }
1788     bdiag[i] = nzbd;
1789     bi[i+1]  = bi[i] + nzi;
1790 
1791     /* if free space is not available, make more free space */
1792     if (current_space->local_remaining<nzi) {
1793       nnz = 2*nzi*(n - i); /* estimated and max additional space needed */
1794       ierr = PetscFreeSpaceGet(nnz,&current_space);CHKERRQ(ierr);
1795       ierr = PetscFreeSpaceGet(nnz,&current_space_lvl);CHKERRQ(ierr);
1796       reallocs++;
1797     }
1798 
1799     /* copy data into free_space and free_space_lvl, then initialize lnk */
1800     ierr = PetscIncompleteLLClean(n,n,nzi,lnk,lnk_lvl,current_space->array,current_space_lvl->array,lnkbt);CHKERRQ(ierr);
1801     bj_ptr[i]    = current_space->array;
1802     bjlvl_ptr[i] = current_space_lvl->array;
1803 
1804     /* make sure the active row i has diagonal entry */
1805     if (*(bj_ptr[i]+bdiag[i]) != i) {
1806       SETERRQ1(PETSC_ERR_MAT_LU_ZRPVT,"Row %D has missing diagonal in factored matrix\n\
1807     try running with -pc_factor_nonzeros_along_diagonal or -pc_factor_diagonal_fill",i);
1808     }
1809 
1810     current_space->array           += nzi;
1811     current_space->local_used      += nzi;
1812     current_space->local_remaining -= nzi;
1813     current_space_lvl->array           += nzi;
1814     current_space_lvl->local_used      += nzi;
1815     current_space_lvl->local_remaining -= nzi;
1816   }
1817 
1818   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
1819   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
1820 
1821   /* destroy list of free space and other temporary arrays */
1822   ierr = PetscMalloc((bi[n]+1)*sizeof(PetscInt),&bj);CHKERRQ(ierr);
1823 
1824   /* copy free_space into bj and free free_space; set bi, bj, bdiag in new datastructure; */
1825   ierr = PetscFreeSpaceContiguous_LU(&free_space,bj,n,bi,bdiag);CHKERRQ(ierr);
1826 
1827   ierr = PetscIncompleteLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
1828   ierr = PetscFreeSpaceDestroy(free_space_lvl);CHKERRQ(ierr);
1829   ierr = PetscFree2(bj_ptr,bjlvl_ptr);CHKERRQ(ierr);
1830 
1831 #if defined(PETSC_USE_INFO)
1832   {
1833     PetscReal af = ((PetscReal)bi[n])/((PetscReal)ai[n]);
1834     ierr = PetscInfo3(A,"Reallocs %D Fill ratio:given %G needed %G\n",reallocs,f,af);CHKERRQ(ierr);
1835     ierr = PetscInfo1(A,"Run with -[sub_]pc_factor_fill %G or use \n",af);CHKERRQ(ierr);
1836     ierr = PetscInfo1(A,"PCFactorSetFill([sub]pc,%G);\n",af);CHKERRQ(ierr);
1837     ierr = PetscInfo(A,"for best performance.\n");CHKERRQ(ierr);
1838     if (diagonal_fill) {
1839       ierr = PetscInfo1(A,"Detected and replaced %D missing diagonals",dcount);CHKERRQ(ierr);
1840     }
1841   }
1842 #endif
1843 
1844   /* put together the new matrix */
1845   ierr = MatSeqAIJSetPreallocation_SeqAIJ(fact,MAT_SKIP_ALLOCATION,PETSC_NULL);CHKERRQ(ierr);
1846   ierr = PetscLogObjectParent(fact,isicol);CHKERRQ(ierr);
1847   b = (Mat_SeqAIJ*)(fact)->data;
1848   b->free_a       = PETSC_TRUE;
1849   b->free_ij      = PETSC_TRUE;
1850   b->singlemalloc = PETSC_FALSE;
1851   ierr = PetscMalloc((bdiag[0]+1)*sizeof(PetscScalar),&b->a);CHKERRQ(ierr);
1852   b->j          = bj;
1853   b->i          = bi;
1854   b->diag       = bdiag;
1855   b->ilen       = 0;
1856   b->imax       = 0;
1857   b->row        = isrow;
1858   b->col        = iscol;
1859   ierr          = PetscObjectReference((PetscObject)isrow);CHKERRQ(ierr);
1860   ierr          = PetscObjectReference((PetscObject)iscol);CHKERRQ(ierr);
1861   b->icol       = isicol;
1862   ierr = PetscMalloc((n+1)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
1863   /* In b structure:  Free imax, ilen, old a, old j.
1864      Allocate bdiag, solve_work, new a, new j */
1865   ierr = PetscLogObjectMemory(fact,(bdiag[0]+1)*(sizeof(PetscInt)+sizeof(PetscScalar)));CHKERRQ(ierr);
1866   b->maxnz = b->nz = bdiag[0]+1;
1867   (fact)->info.factor_mallocs    = reallocs;
1868   (fact)->info.fill_ratio_given  = f;
1869   (fact)->info.fill_ratio_needed = ((PetscReal)(bdiag[0]+1))/((PetscReal)ai[n]);
1870   (fact)->ops->lufactornumeric = MatLUFactorNumeric_SeqAIJ;
1871   ierr = Mat_CheckInode_FactorLU(fact,PETSC_FALSE);CHKERRQ(ierr);
1872   PetscFunctionReturn(0);
1873 }
1874 
1875 #undef __FUNCT__
1876 #define __FUNCT__ "MatILUFactorSymbolic_SeqAIJ_inplace"
1877 PetscErrorCode MatILUFactorSymbolic_SeqAIJ_inplace(Mat fact,Mat A,IS isrow,IS iscol,const MatFactorInfo *info)
1878 {
1879   Mat_SeqAIJ         *a = (Mat_SeqAIJ*)A->data,*b;
1880   IS                 isicol;
1881   PetscErrorCode     ierr;
1882   const PetscInt     *r,*ic;
1883   PetscInt           n=A->rmap->n,*ai=a->i,*aj=a->j,d;
1884   PetscInt           *bi,*cols,nnz,*cols_lvl;
1885   PetscInt           *bdiag,prow,fm,nzbd,reallocs=0,dcount=0;
1886   PetscInt           i,levels,diagonal_fill;
1887   PetscTruth         col_identity,row_identity;
1888   PetscReal          f;
1889   PetscInt           nlnk,*lnk,*lnk_lvl=PETSC_NULL;
1890   PetscBT            lnkbt;
1891   PetscInt           nzi,*bj,**bj_ptr,**bjlvl_ptr;
1892   PetscFreeSpaceList free_space=PETSC_NULL,current_space=PETSC_NULL;
1893   PetscFreeSpaceList free_space_lvl=PETSC_NULL,current_space_lvl=PETSC_NULL;
1894   PetscTruth         missing;
1895 
1896   PetscFunctionBegin;
1897   if (A->rmap->n != A->cmap->n) SETERRQ2(PETSC_ERR_ARG_WRONG,"Must be square matrix, rows %D columns %D",A->rmap->n,A->cmap->n);
1898   f             = info->fill;
1899   levels        = (PetscInt)info->levels;
1900   diagonal_fill = (PetscInt)info->diagonal_fill;
1901   ierr = ISInvertPermutation(iscol,PETSC_DECIDE,&isicol);CHKERRQ(ierr);
1902 
1903   ierr = ISIdentity(isrow,&row_identity);CHKERRQ(ierr);
1904   ierr = ISIdentity(iscol,&col_identity);CHKERRQ(ierr);
1905   if (!levels && row_identity && col_identity) { /* special case: ilu(0) with natural ordering */
1906     ierr = MatDuplicateNoCreate_SeqAIJ(fact,A,MAT_DO_NOT_COPY_VALUES,PETSC_TRUE);CHKERRQ(ierr);
1907     (fact)->ops->lufactornumeric =  MatLUFactorNumeric_SeqAIJ_inplace;
1908 
1909     fact->factor = MAT_FACTOR_ILU;
1910     (fact)->info.factor_mallocs    = 0;
1911     (fact)->info.fill_ratio_given  = info->fill;
1912     (fact)->info.fill_ratio_needed = 1.0;
1913     b               = (Mat_SeqAIJ*)(fact)->data;
1914     ierr = MatMissingDiagonal(A,&missing,&d);CHKERRQ(ierr);
1915     if (missing) SETERRQ1(PETSC_ERR_ARG_WRONGSTATE,"Matrix is missing diagonal entry %D",d);
1916     b->row              = isrow;
1917     b->col              = iscol;
1918     b->icol             = isicol;
1919     ierr                = PetscMalloc(((fact)->rmap->n+1)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
1920     ierr                = PetscObjectReference((PetscObject)isrow);CHKERRQ(ierr);
1921     ierr                = PetscObjectReference((PetscObject)iscol);CHKERRQ(ierr);
1922     ierr = MatILUFactorSymbolic_SeqAIJ_Inode(fact,A,isrow,iscol,info);CHKERRQ(ierr);
1923     PetscFunctionReturn(0);
1924   }
1925 
1926   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
1927   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
1928 
1929   /* get new row and diagonal pointers, must be allocated separately because they will be given to the Mat_SeqAIJ and freed separately */
1930   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bi);CHKERRQ(ierr);
1931   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bdiag);CHKERRQ(ierr);
1932   bi[0] = bdiag[0] = 0;
1933 
1934   ierr = PetscMalloc2(n,PetscInt*,&bj_ptr,n,PetscInt*,&bjlvl_ptr);CHKERRQ(ierr);
1935 
1936   /* create a linked list for storing column indices of the active row */
1937   nlnk = n + 1;
1938   ierr = PetscIncompleteLLCreate(n,n,nlnk,lnk,lnk_lvl,lnkbt);CHKERRQ(ierr);
1939 
1940   /* initial FreeSpace size is f*(ai[n]+1) */
1941   ierr = PetscFreeSpaceGet((PetscInt)(f*(ai[n]+1)),&free_space);CHKERRQ(ierr);
1942   current_space = free_space;
1943   ierr = PetscFreeSpaceGet((PetscInt)(f*(ai[n]+1)),&free_space_lvl);CHKERRQ(ierr);
1944   current_space_lvl = free_space_lvl;
1945 
1946   for (i=0; i<n; i++) {
1947     nzi = 0;
1948     /* copy current row into linked list */
1949     nnz  = ai[r[i]+1] - ai[r[i]];
1950     if (!nnz) SETERRQ2(PETSC_ERR_MAT_LU_ZRPVT,"Empty row in matrix: row in original ordering %D in permuted ordering %D",r[i],i);
1951     cols = aj + ai[r[i]];
1952     lnk[i] = -1; /* marker to indicate if diagonal exists */
1953     ierr = PetscIncompleteLLInit(nnz,cols,n,ic,nlnk,lnk,lnk_lvl,lnkbt);CHKERRQ(ierr);
1954     nzi += nlnk;
1955 
1956     /* make sure diagonal entry is included */
1957     if (diagonal_fill && lnk[i] == -1) {
1958       fm = n;
1959       while (lnk[fm] < i) fm = lnk[fm];
1960       lnk[i]     = lnk[fm]; /* insert diagonal into linked list */
1961       lnk[fm]    = i;
1962       lnk_lvl[i] = 0;
1963       nzi++; dcount++;
1964     }
1965 
1966     /* add pivot rows into the active row */
1967     nzbd = 0;
1968     prow = lnk[n];
1969     while (prow < i) {
1970       nnz      = bdiag[prow];
1971       cols     = bj_ptr[prow] + nnz + 1;
1972       cols_lvl = bjlvl_ptr[prow] + nnz + 1;
1973       nnz      = bi[prow+1] - bi[prow] - nnz - 1;
1974       ierr = PetscILULLAddSorted(nnz,cols,levels,cols_lvl,prow,nlnk,lnk,lnk_lvl,lnkbt,prow);CHKERRQ(ierr);
1975       nzi += nlnk;
1976       prow = lnk[prow];
1977       nzbd++;
1978     }
1979     bdiag[i] = nzbd;
1980     bi[i+1]  = bi[i] + nzi;
1981 
1982     /* if free space is not available, make more free space */
1983     if (current_space->local_remaining<nzi) {
1984       nnz = nzi*(n - i); /* estimated and max additional space needed */
1985       ierr = PetscFreeSpaceGet(nnz,&current_space);CHKERRQ(ierr);
1986       ierr = PetscFreeSpaceGet(nnz,&current_space_lvl);CHKERRQ(ierr);
1987       reallocs++;
1988     }
1989 
1990     /* copy data into free_space and free_space_lvl, then initialize lnk */
1991     ierr = PetscIncompleteLLClean(n,n,nzi,lnk,lnk_lvl,current_space->array,current_space_lvl->array,lnkbt);CHKERRQ(ierr);
1992     bj_ptr[i]    = current_space->array;
1993     bjlvl_ptr[i] = current_space_lvl->array;
1994 
1995     /* make sure the active row i has diagonal entry */
1996     if (*(bj_ptr[i]+bdiag[i]) != i) {
1997       SETERRQ1(PETSC_ERR_MAT_LU_ZRPVT,"Row %D has missing diagonal in factored matrix\n\
1998     try running with -pc_factor_nonzeros_along_diagonal or -pc_factor_diagonal_fill",i);
1999     }
2000 
2001     current_space->array           += nzi;
2002     current_space->local_used      += nzi;
2003     current_space->local_remaining -= nzi;
2004     current_space_lvl->array           += nzi;
2005     current_space_lvl->local_used      += nzi;
2006     current_space_lvl->local_remaining -= nzi;
2007   }
2008 
2009   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
2010   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
2011 
2012   /* destroy list of free space and other temporary arrays */
2013   ierr = PetscMalloc((bi[n]+1)*sizeof(PetscInt),&bj);CHKERRQ(ierr);
2014   ierr = PetscFreeSpaceContiguous(&free_space,bj);CHKERRQ(ierr); /* copy free_space -> bj */
2015   ierr = PetscIncompleteLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
2016   ierr = PetscFreeSpaceDestroy(free_space_lvl);CHKERRQ(ierr);
2017   ierr = PetscFree2(bj_ptr,bjlvl_ptr);CHKERRQ(ierr);
2018 
2019 #if defined(PETSC_USE_INFO)
2020   {
2021     PetscReal af = ((PetscReal)bi[n])/((PetscReal)ai[n]);
2022     ierr = PetscInfo3(A,"Reallocs %D Fill ratio:given %G needed %G\n",reallocs,f,af);CHKERRQ(ierr);
2023     ierr = PetscInfo1(A,"Run with -[sub_]pc_factor_fill %G or use \n",af);CHKERRQ(ierr);
2024     ierr = PetscInfo1(A,"PCFactorSetFill([sub]pc,%G);\n",af);CHKERRQ(ierr);
2025     ierr = PetscInfo(A,"for best performance.\n");CHKERRQ(ierr);
2026     if (diagonal_fill) {
2027       ierr = PetscInfo1(A,"Detected and replaced %D missing diagonals",dcount);CHKERRQ(ierr);
2028     }
2029   }
2030 #endif
2031 
2032   /* put together the new matrix */
2033   ierr = MatSeqAIJSetPreallocation_SeqAIJ(fact,MAT_SKIP_ALLOCATION,PETSC_NULL);CHKERRQ(ierr);
2034   ierr = PetscLogObjectParent(fact,isicol);CHKERRQ(ierr);
2035   b = (Mat_SeqAIJ*)(fact)->data;
2036   b->free_a       = PETSC_TRUE;
2037   b->free_ij      = PETSC_TRUE;
2038   b->singlemalloc = PETSC_FALSE;
2039   ierr = PetscMalloc(bi[n]*sizeof(PetscScalar),&b->a);CHKERRQ(ierr);
2040   b->j          = bj;
2041   b->i          = bi;
2042   for (i=0; i<n; i++) bdiag[i] += bi[i];
2043   b->diag       = bdiag;
2044   b->ilen       = 0;
2045   b->imax       = 0;
2046   b->row        = isrow;
2047   b->col        = iscol;
2048   ierr          = PetscObjectReference((PetscObject)isrow);CHKERRQ(ierr);
2049   ierr          = PetscObjectReference((PetscObject)iscol);CHKERRQ(ierr);
2050   b->icol       = isicol;
2051   ierr = PetscMalloc((n+1)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
2052   /* In b structure:  Free imax, ilen, old a, old j.
2053      Allocate bdiag, solve_work, new a, new j */
2054   ierr = PetscLogObjectMemory(fact,(bi[n]-n) * (sizeof(PetscInt)+sizeof(PetscScalar)));CHKERRQ(ierr);
2055   b->maxnz             = b->nz = bi[n] ;
2056   (fact)->info.factor_mallocs    = reallocs;
2057   (fact)->info.fill_ratio_given  = f;
2058   (fact)->info.fill_ratio_needed = ((PetscReal)bi[n])/((PetscReal)ai[n]);
2059   (fact)->ops->lufactornumeric =  MatLUFactorNumeric_SeqAIJ_inplace;
2060   ierr = MatILUFactorSymbolic_SeqAIJ_Inode(fact,A,isrow,iscol,info);CHKERRQ(ierr);
2061   PetscFunctionReturn(0);
2062 }
2063 
2064 #undef __FUNCT__
2065 #define __FUNCT__ "MatCholeskyFactorNumeric_SeqAIJ"
2066 PetscErrorCode MatCholeskyFactorNumeric_SeqAIJ(Mat B,Mat A,const MatFactorInfo *info)
2067 {
2068   Mat            C = B;
2069   Mat_SeqAIJ     *a=(Mat_SeqAIJ*)A->data;
2070   Mat_SeqSBAIJ   *b=(Mat_SeqSBAIJ*)C->data;
2071   IS             ip=b->row,iip = b->icol;
2072   PetscErrorCode ierr;
2073   const PetscInt *rip,*riip;
2074   PetscInt       i,j,mbs=A->rmap->n,*bi=b->i,*bj=b->j,*bdiag=b->diag,*bjtmp;
2075   PetscInt       *ai=a->i,*aj=a->j;
2076   PetscInt       k,jmin,jmax,*c2r,*il,col,nexti,ili,nz;
2077   MatScalar      *rtmp,*ba=b->a,*bval,*aa=a->a,dk,uikdi;
2078   PetscTruth     perm_identity;
2079 
2080   FactorShiftCtx sctx;
2081   PetscReal      rs;
2082   MatScalar      d,*v;
2083 
2084   PetscFunctionBegin;
2085   /* MatPivotSetUp(): initialize shift context sctx */
2086   ierr = PetscMemzero(&sctx,sizeof(FactorShiftCtx));CHKERRQ(ierr);
2087 
2088   /* if both shift schemes are chosen by user, only use info->shiftpd */
2089   if (info->shiftpd) { /* set sctx.shift_top=max{rs} */
2090     sctx.shift_top = info->zeropivot;
2091     for (i=0; i<mbs; i++) {
2092       /* calculate sum(|aij|)-RealPart(aii), amt of shift needed for this row */
2093       d  = (aa)[a->diag[i]];
2094       rs = -PetscAbsScalar(d) - PetscRealPart(d);
2095       v  = aa+ai[i];
2096       nz = ai[i+1] - ai[i];
2097       for (j=0; j<nz; j++)
2098 	rs += PetscAbsScalar(v[j]);
2099       if (rs>sctx.shift_top) sctx.shift_top = rs;
2100     }
2101     sctx.shift_top   *= 1.1;
2102     sctx.nshift_max   = 5;
2103     sctx.shift_lo     = 0.;
2104     sctx.shift_hi     = 1.;
2105   }
2106 
2107   ierr  = ISGetIndices(ip,&rip);CHKERRQ(ierr);
2108   ierr  = ISGetIndices(iip,&riip);CHKERRQ(ierr);
2109 
2110   /* allocate working arrays
2111      c2r: linked list, keep track of pivot rows for a given column. c2r[col]: head of the list for a given col
2112      il:  for active k row, il[i] gives the index of the 1st nonzero entry in U[i,k:n-1] in bj and ba arrays
2113   */
2114   ierr = PetscMalloc3(mbs,MatScalar,&rtmp,mbs,PetscInt,&il,mbs,PetscInt,&c2r);CHKERRQ(ierr);
2115 
2116   do {
2117     sctx.useshift = PETSC_FALSE;
2118 
2119     for (i=0; i<mbs; i++) c2r[i] = mbs;
2120     il[0] = 0;
2121 
2122     for (k = 0; k<mbs; k++){
2123       /* zero rtmp */
2124       nz = bi[k+1] - bi[k];
2125       bjtmp = bj + bi[k];
2126       for (j=0; j<nz; j++) rtmp[bjtmp[j]] = 0.0;
2127 
2128       /* load in initial unfactored row */
2129       bval = ba + bi[k];
2130       jmin = ai[rip[k]]; jmax = ai[rip[k]+1];
2131       for (j = jmin; j < jmax; j++){
2132         col = riip[aj[j]];
2133         if (col >= k){ /* only take upper triangular entry */
2134           rtmp[col] = aa[j];
2135           *bval++   = 0.0; /* for in-place factorization */
2136         }
2137       }
2138       /* shift the diagonal of the matrix: ZeropivotApply() */
2139       rtmp[k] += sctx.shift_amount;  /* shift the diagonal of the matrix */
2140 
2141       /* modify k-th row by adding in those rows i with U(i,k)!=0 */
2142       dk = rtmp[k];
2143       i  = c2r[k]; /* first row to be added to k_th row  */
2144 
2145       while (i < k){
2146         nexti = c2r[i]; /* next row to be added to k_th row */
2147 
2148         /* compute multiplier, update diag(k) and U(i,k) */
2149         ili   = il[i];  /* index of first nonzero element in U(i,k:bms-1) */
2150         uikdi = - ba[ili]*ba[bdiag[i]];  /* diagonal(k) */
2151         dk   += uikdi*ba[ili]; /* update diag[k] */
2152         ba[ili] = uikdi; /* -U(i,k) */
2153 
2154         /* add multiple of row i to k-th row */
2155         jmin = ili + 1; jmax = bi[i+1];
2156         if (jmin < jmax){
2157           for (j=jmin; j<jmax; j++) rtmp[bj[j]] += uikdi*ba[j];
2158           /* update il and c2r for row i */
2159           il[i] = jmin;
2160           j = bj[jmin]; c2r[i] = c2r[j]; c2r[j] = i;
2161         }
2162         i = nexti;
2163       }
2164 
2165       /* copy data into U(k,:) */
2166       rs   = 0.0;
2167       jmin = bi[k]; jmax = bi[k+1]-1;
2168       if (jmin < jmax) {
2169         for (j=jmin; j<jmax; j++){
2170           col = bj[j]; ba[j] = rtmp[col]; rs += PetscAbsScalar(ba[j]);
2171         }
2172         /* add the k-th row into il and c2r */
2173         il[k] = jmin;
2174         i = bj[jmin]; c2r[k] = c2r[i]; c2r[i] = k;
2175       }
2176 
2177       /* MatPivotCheck() */
2178       sctx.rs  = rs;
2179       sctx.pv  = dk;
2180       if (info->shiftnz){
2181         ierr = MatPivotCheck_nz(info,sctx,k);CHKERRQ(ierr);
2182       } else if (info->shiftpd){
2183         ierr = MatPivotCheck_pd(info,sctx,k);CHKERRQ(ierr);
2184       } else if (info->shiftinblocks){
2185         ierr = MatPivotCheck_inblocks(info,sctx,k);CHKERRQ(ierr);
2186       } else {
2187         ierr = MatPivotCheck_none(info,sctx,k);CHKERRQ(ierr);
2188       }
2189       dk = sctx.pv;
2190 
2191       ba[bdiag[k]] = 1.0/dk; /* U(k,k) */
2192     }
2193   } while (sctx.useshift);
2194 
2195   ierr = PetscFree3(rtmp,il,c2r);CHKERRQ(ierr);
2196   ierr = ISRestoreIndices(ip,&rip);CHKERRQ(ierr);
2197   ierr = ISRestoreIndices(iip,&riip);CHKERRQ(ierr);
2198 
2199   ierr = ISIdentity(ip,&perm_identity);CHKERRQ(ierr);
2200   if (perm_identity){
2201     B->ops->solve           = MatSolve_SeqSBAIJ_1_NaturalOrdering;
2202     B->ops->solvetranspose  = MatSolve_SeqSBAIJ_1_NaturalOrdering;
2203     B->ops->forwardsolve    = MatForwardSolve_SeqSBAIJ_1_NaturalOrdering;
2204     B->ops->backwardsolve   = MatBackwardSolve_SeqSBAIJ_1_NaturalOrdering;
2205   } else {
2206     B->ops->solve           = MatSolve_SeqSBAIJ_1;
2207     B->ops->solvetranspose  = MatSolve_SeqSBAIJ_1;
2208     B->ops->forwardsolve    = MatForwardSolve_SeqSBAIJ_1;
2209     B->ops->backwardsolve   = MatBackwardSolve_SeqSBAIJ_1;
2210   }
2211 
2212   C->assembled    = PETSC_TRUE;
2213   C->preallocated = PETSC_TRUE;
2214   ierr = PetscLogFlops(C->rmap->n);CHKERRQ(ierr);
2215 
2216   /* MatPivotView() */
2217   if (sctx.nshift){
2218     if (info->shiftpd) {
2219       ierr = PetscInfo4(A,"number of shift_pd tries %D, shift_amount %G, diagonal shifted up by %e fraction top_value %e\n",sctx.nshift,sctx.shift_amount,sctx.shift_fraction,sctx.shift_top);CHKERRQ(ierr);
2220     } else if (info->shiftnz) {
2221       ierr = PetscInfo2(A,"number of shift_nz tries %D, shift_amount %G\n",sctx.nshift,sctx.shift_amount);CHKERRQ(ierr);
2222     } else if (info->shiftinblocks){
2223       ierr = PetscInfo2(A,"number of shift_inblocks applied %D, each shift_amount %G\n",sctx.nshift,info->shiftinblocks);CHKERRQ(ierr);
2224     }
2225   }
2226   PetscFunctionReturn(0);
2227 }
2228 
2229 #undef __FUNCT__
2230 #define __FUNCT__ "MatCholeskyFactorNumeric_SeqAIJ_inplace"
2231 PetscErrorCode MatCholeskyFactorNumeric_SeqAIJ_inplace(Mat B,Mat A,const MatFactorInfo *info)
2232 {
2233   Mat            C = B;
2234   Mat_SeqAIJ     *a=(Mat_SeqAIJ*)A->data;
2235   Mat_SeqSBAIJ   *b=(Mat_SeqSBAIJ*)C->data;
2236   IS             ip=b->row,iip = b->icol;
2237   PetscErrorCode ierr;
2238   const PetscInt *rip,*riip;
2239   PetscInt       i,j,mbs=A->rmap->n,*bi=b->i,*bj=b->j,*bcol,*bjtmp;
2240   PetscInt       *ai=a->i,*aj=a->j;
2241   PetscInt       k,jmin,jmax,*jl,*il,col,nexti,ili,nz;
2242   MatScalar      *rtmp,*ba=b->a,*bval,*aa=a->a,dk,uikdi;
2243   PetscReal      zeropivot,rs,shiftnz;
2244   PetscReal      shiftpd;
2245   ChShift_Ctx    sctx;
2246   PetscInt       newshift;
2247   PetscTruth     perm_identity;
2248 
2249   PetscFunctionBegin;
2250   shiftnz   = info->shiftnz;
2251   shiftpd   = info->shiftpd;
2252   zeropivot = info->zeropivot;
2253 
2254   ierr  = ISGetIndices(ip,&rip);CHKERRQ(ierr);
2255   ierr  = ISGetIndices(iip,&riip);CHKERRQ(ierr);
2256 
2257   /* initialization */
2258   ierr = PetscMalloc3(mbs,MatScalar,&rtmp,mbs,PetscInt,&il,mbs,PetscInt,&jl);CHKERRQ(ierr);
2259   sctx.shift_amount = 0;
2260   sctx.nshift       = 0;
2261   do {
2262     sctx.chshift = PETSC_FALSE;
2263     for (i=0; i<mbs; i++) jl[i] = mbs;
2264     il[0] = 0;
2265 
2266     for (k = 0; k<mbs; k++){
2267       /* zero rtmp */
2268       nz = bi[k+1] - bi[k];
2269       bjtmp = bj + bi[k];
2270       for (j=0; j<nz; j++) rtmp[bjtmp[j]] = 0.0;
2271 
2272       bval = ba + bi[k];
2273       /* initialize k-th row by the perm[k]-th row of A */
2274       jmin = ai[rip[k]]; jmax = ai[rip[k]+1];
2275       for (j = jmin; j < jmax; j++){
2276         col = riip[aj[j]];
2277         if (col >= k){ /* only take upper triangular entry */
2278           rtmp[col] = aa[j];
2279           *bval++  = 0.0; /* for in-place factorization */
2280         }
2281       }
2282       /* shift the diagonal of the matrix */
2283       if (sctx.nshift) rtmp[k] += sctx.shift_amount;
2284 
2285       /* modify k-th row by adding in those rows i with U(i,k)!=0 */
2286       dk = rtmp[k];
2287       i = jl[k]; /* first row to be added to k_th row  */
2288 
2289       while (i < k){
2290         nexti = jl[i]; /* next row to be added to k_th row */
2291 
2292         /* compute multiplier, update diag(k) and U(i,k) */
2293         ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */
2294         uikdi = - ba[ili]*ba[bi[i]];  /* diagonal(k) */
2295         dk += uikdi*ba[ili];
2296         ba[ili] = uikdi; /* -U(i,k) */
2297 
2298         /* add multiple of row i to k-th row */
2299         jmin = ili + 1; jmax = bi[i+1];
2300         if (jmin < jmax){
2301           for (j=jmin; j<jmax; j++) rtmp[bj[j]] += uikdi*ba[j];
2302           /* update il and jl for row i */
2303           il[i] = jmin;
2304           j = bj[jmin]; jl[i] = jl[j]; jl[j] = i;
2305         }
2306         i = nexti;
2307       }
2308 
2309       /* shift the diagonals when zero pivot is detected */
2310       /* compute rs=sum of abs(off-diagonal) */
2311       rs   = 0.0;
2312       jmin = bi[k]+1;
2313       nz   = bi[k+1] - jmin;
2314       bcol = bj + jmin;
2315       for (j=0; j<nz; j++) {
2316         rs += PetscAbsScalar(rtmp[bcol[j]]);
2317       }
2318 
2319       sctx.rs = rs;
2320       sctx.pv = dk;
2321       ierr = MatCholeskyCheckShift_inline(info,sctx,k,newshift);CHKERRQ(ierr);
2322 
2323       if (newshift == 1) {
2324         if (!sctx.shift_amount) {
2325           sctx.shift_amount = 1e-5;
2326         }
2327         break;
2328       }
2329 
2330       /* copy data into U(k,:) */
2331       ba[bi[k]] = 1.0/dk; /* U(k,k) */
2332       jmin = bi[k]+1; jmax = bi[k+1];
2333       if (jmin < jmax) {
2334         for (j=jmin; j<jmax; j++){
2335           col = bj[j]; ba[j] = rtmp[col];
2336         }
2337         /* add the k-th row into il and jl */
2338         il[k] = jmin;
2339         i = bj[jmin]; jl[k] = jl[i]; jl[i] = k;
2340       }
2341     }
2342   } while (sctx.chshift);
2343   ierr = PetscFree3(rtmp,il,jl);CHKERRQ(ierr);
2344   ierr = ISRestoreIndices(ip,&rip);CHKERRQ(ierr);
2345   ierr = ISRestoreIndices(iip,&riip);CHKERRQ(ierr);
2346 
2347   ierr = ISIdentity(ip,&perm_identity);CHKERRQ(ierr);
2348   if (perm_identity){
2349     B->ops->solve           = MatSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
2350     B->ops->solvetranspose  = MatSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
2351     B->ops->forwardsolve    = MatForwardSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
2352     B->ops->backwardsolve   = MatBackwardSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
2353   } else {
2354     B->ops->solve           = MatSolve_SeqSBAIJ_1_inplace;
2355     B->ops->solvetranspose  = MatSolve_SeqSBAIJ_1_inplace;
2356     B->ops->forwardsolve    = MatForwardSolve_SeqSBAIJ_1_inplace;
2357     B->ops->backwardsolve   = MatBackwardSolve_SeqSBAIJ_1_inplace;
2358   }
2359 
2360   C->assembled    = PETSC_TRUE;
2361   C->preallocated = PETSC_TRUE;
2362   ierr = PetscLogFlops(C->rmap->n);CHKERRQ(ierr);
2363   if (sctx.nshift){
2364     if (shiftnz) {
2365       ierr = PetscInfo2(A,"number of shiftnz tries %D, shift_amount %G\n",sctx.nshift,sctx.shift_amount);CHKERRQ(ierr);
2366     } else if (shiftpd) {
2367       ierr = PetscInfo2(A,"number of shiftpd tries %D, shift_amount %G\n",sctx.nshift,sctx.shift_amount);CHKERRQ(ierr);
2368     }
2369   }
2370   PetscFunctionReturn(0);
2371 }
2372 
2373 /*
2374    icc() under revised new data structure.
2375    Factored arrays bj and ba are stored as
2376      U(0,:),...,U(i,:),U(n-1,:)
2377 
2378    ui=fact->i is an array of size n+1, in which
2379    ui+
2380      ui[i]:  points to 1st entry of U(i,:),i=0,...,n-1
2381      ui[n]:  points to U(n-1,n-1)+1
2382 
2383   udiag=fact->diag is an array of size n,in which
2384      udiag[i]: points to diagonal of U(i,:), i=0,...,n-1
2385 
2386    U(i,:) contains udiag[i] as its last entry, i.e.,
2387     U(i,:) = (u[i,i+1],...,u[i,n-1],diag[i])
2388 */
2389 
2390 #undef __FUNCT__
2391 #define __FUNCT__ "MatICCFactorSymbolic_SeqAIJ"
2392 PetscErrorCode MatICCFactorSymbolic_SeqAIJ(Mat fact,Mat A,IS perm,const MatFactorInfo *info)
2393 {
2394   Mat_SeqAIJ         *a = (Mat_SeqAIJ*)A->data;
2395   Mat_SeqSBAIJ       *b;
2396   PetscErrorCode     ierr;
2397   PetscTruth         perm_identity,missing;
2398   PetscInt           reallocs=0,i,*ai=a->i,*aj=a->j,am=A->rmap->n,*ui,*udiag;
2399   const PetscInt     *rip,*riip;
2400   PetscInt           jmin,jmax,nzk,k,j,*jl,prow,*il,nextprow;
2401   PetscInt           nlnk,*lnk,*lnk_lvl=PETSC_NULL,d;
2402   PetscInt           ncols,ncols_upper,*cols,*ajtmp,*uj,**uj_ptr,**uj_lvl_ptr;
2403   PetscReal          fill=info->fill,levels=info->levels;
2404   PetscFreeSpaceList free_space=PETSC_NULL,current_space=PETSC_NULL;
2405   PetscFreeSpaceList free_space_lvl=PETSC_NULL,current_space_lvl=PETSC_NULL;
2406   PetscBT            lnkbt;
2407   IS                 iperm;
2408 
2409   PetscFunctionBegin;
2410   if (A->rmap->n != A->cmap->n) SETERRQ2(PETSC_ERR_ARG_WRONG,"Must be square matrix, rows %D columns %D",A->rmap->n,A->cmap->n);
2411   ierr = MatMissingDiagonal(A,&missing,&d);CHKERRQ(ierr);
2412   if (missing) SETERRQ1(PETSC_ERR_ARG_WRONGSTATE,"Matrix is missing diagonal entry %D",d);
2413   ierr = ISIdentity(perm,&perm_identity);CHKERRQ(ierr);
2414   ierr = ISInvertPermutation(perm,PETSC_DECIDE,&iperm);CHKERRQ(ierr);
2415 
2416   ierr = PetscMalloc((am+1)*sizeof(PetscInt),&ui);CHKERRQ(ierr);
2417   ierr = PetscMalloc((am+1)*sizeof(PetscInt),&udiag);CHKERRQ(ierr);
2418   ui[0] = 0;
2419 
2420   /* ICC(0) without matrix ordering: simply rearrange column indices */
2421   if (!levels && perm_identity) {
2422     for (i=0; i<am; i++) {
2423       ncols    = ai[i+1] - a->diag[i];
2424       ui[i+1]  = ui[i] + ncols;
2425       udiag[i] = ui[i+1] - 1; /* points to the last entry of U(i,:) */
2426     }
2427     ierr = PetscMalloc((ui[am]+1)*sizeof(PetscInt),&uj);CHKERRQ(ierr);
2428     cols = uj;
2429     for (i=0; i<am; i++) {
2430       aj    = a->j + a->diag[i] + 1; /* 1st entry of U(i,:) without diagonal */
2431       ncols = ai[i+1] - a->diag[i] -1;
2432       for (j=0; j<ncols; j++) *cols++ = aj[j];
2433       *cols++ = i; /* diagoanl is located as the last entry of U(i,:) */
2434     }
2435   } else { /* case: levels>0 || (levels=0 && !perm_identity) */
2436     ierr = ISGetIndices(iperm,&riip);CHKERRQ(ierr);
2437     ierr = ISGetIndices(perm,&rip);CHKERRQ(ierr);
2438 
2439     /* initialization */
2440     ierr  = PetscMalloc((am+1)*sizeof(PetscInt),&ajtmp);CHKERRQ(ierr);
2441 
2442     /* jl: linked list for storing indices of the pivot rows
2443        il: il[i] points to the 1st nonzero entry of U(i,k:am-1) */
2444     ierr = PetscMalloc4(am,PetscInt*,&uj_ptr,am,PetscInt*,&uj_lvl_ptr,am,PetscInt,&jl,am,PetscInt,&il);CHKERRQ(ierr);
2445     for (i=0; i<am; i++){
2446       jl[i] = am; il[i] = 0;
2447     }
2448 
2449     /* create and initialize a linked list for storing column indices of the active row k */
2450     nlnk = am + 1;
2451     ierr = PetscIncompleteLLCreate(am,am,nlnk,lnk,lnk_lvl,lnkbt);CHKERRQ(ierr);
2452 
2453     /* initial FreeSpace size is fill*(ai[am]+1) */
2454     ierr = PetscFreeSpaceGet((PetscInt)(fill*(ai[am]+1)),&free_space);CHKERRQ(ierr);
2455     current_space = free_space;
2456     ierr = PetscFreeSpaceGet((PetscInt)(fill*(ai[am]+1)),&free_space_lvl);CHKERRQ(ierr);
2457     current_space_lvl = free_space_lvl;
2458 
2459     for (k=0; k<am; k++){  /* for each active row k */
2460       /* initialize lnk by the column indices of row rip[k] of A */
2461       nzk   = 0;
2462       ncols = ai[rip[k]+1] - ai[rip[k]];
2463       if (!ncols) SETERRQ2(PETSC_ERR_MAT_CH_ZRPVT,"Empty row in matrix: row in original ordering %D in permuted ordering %D",rip[k],k);
2464       ncols_upper = 0;
2465       for (j=0; j<ncols; j++){
2466         i = *(aj + ai[rip[k]] + j); /* unpermuted column index */
2467         if (riip[i] >= k){ /* only take upper triangular entry */
2468           ajtmp[ncols_upper] = i;
2469           ncols_upper++;
2470         }
2471       }
2472       ierr = PetscIncompleteLLInit(ncols_upper,ajtmp,am,riip,nlnk,lnk,lnk_lvl,lnkbt);CHKERRQ(ierr);
2473       nzk += nlnk;
2474 
2475       /* update lnk by computing fill-in for each pivot row to be merged in */
2476       prow = jl[k]; /* 1st pivot row */
2477 
2478       while (prow < k){
2479         nextprow = jl[prow];
2480 
2481         /* merge prow into k-th row */
2482         jmin = il[prow] + 1;  /* index of the 2nd nzero entry in U(prow,k:am-1) */
2483         jmax = ui[prow+1];
2484         ncols = jmax-jmin;
2485         i     = jmin - ui[prow];
2486         cols  = uj_ptr[prow] + i; /* points to the 2nd nzero entry in U(prow,k:am-1) */
2487         uj    = uj_lvl_ptr[prow] + i; /* levels of cols */
2488         j     = *(uj - 1);
2489         ierr = PetscICCLLAddSorted(ncols,cols,levels,uj,am,nlnk,lnk,lnk_lvl,lnkbt,j);CHKERRQ(ierr);
2490         nzk += nlnk;
2491 
2492         /* update il and jl for prow */
2493         if (jmin < jmax){
2494           il[prow] = jmin;
2495           j = *cols; jl[prow] = jl[j]; jl[j] = prow;
2496         }
2497         prow = nextprow;
2498       }
2499 
2500       /* if free space is not available, make more free space */
2501       if (current_space->local_remaining<nzk) {
2502         i  = am - k + 1; /* num of unfactored rows */
2503         i *= PetscMin(nzk, i-1); /* i*nzk, i*(i-1): estimated and max additional space needed */
2504         ierr = PetscFreeSpaceGet(i,&current_space);CHKERRQ(ierr);
2505         ierr = PetscFreeSpaceGet(i,&current_space_lvl);CHKERRQ(ierr);
2506         reallocs++;
2507       }
2508 
2509       /* copy data into free_space and free_space_lvl, then initialize lnk */
2510       if (nzk == 0) SETERRQ1(PETSC_ERR_ARG_WRONG,"Empty row %D in ICC matrix factor",k);
2511       ierr = PetscIncompleteLLClean(am,am,nzk,lnk,lnk_lvl,current_space->array,current_space_lvl->array,lnkbt);CHKERRQ(ierr);
2512 
2513       /* add the k-th row into il and jl */
2514       if (nzk > 1){
2515         i = current_space->array[1]; /* col value of the first nonzero element in U(k, k+1:am-1) */
2516         jl[k] = jl[i]; jl[i] = k;
2517         il[k] = ui[k] + 1;
2518       }
2519       uj_ptr[k]     = current_space->array;
2520       uj_lvl_ptr[k] = current_space_lvl->array;
2521 
2522       current_space->array           += nzk;
2523       current_space->local_used      += nzk;
2524       current_space->local_remaining -= nzk;
2525 
2526       current_space_lvl->array           += nzk;
2527       current_space_lvl->local_used      += nzk;
2528       current_space_lvl->local_remaining -= nzk;
2529 
2530       ui[k+1] = ui[k] + nzk;
2531     }
2532 
2533 #if defined(PETSC_USE_INFO)
2534     if (ai[am] != 0) {
2535       PetscReal af = (PetscReal)ui[am]/((PetscReal)ai[am]);
2536       ierr = PetscInfo3(A,"Reallocs %D Fill ratio:given %G needed %G\n",reallocs,fill,af);CHKERRQ(ierr);
2537       ierr = PetscInfo1(A,"Run with -pc_factor_fill %G or use \n",af);CHKERRQ(ierr);
2538       ierr = PetscInfo1(A,"PCFactorSetFill(pc,%G) for best performance.\n",af);CHKERRQ(ierr);
2539     } else {
2540       ierr = PetscInfo(A,"Empty matrix.\n");CHKERRQ(ierr);
2541     }
2542 #endif
2543 
2544     ierr = ISRestoreIndices(perm,&rip);CHKERRQ(ierr);
2545     ierr = ISRestoreIndices(iperm,&riip);CHKERRQ(ierr);
2546     ierr = PetscFree4(uj_ptr,uj_lvl_ptr,jl,il);CHKERRQ(ierr);
2547     ierr = PetscFree(ajtmp);CHKERRQ(ierr);
2548 
2549     /* destroy list of free space and other temporary array(s) */
2550     ierr = PetscMalloc((ui[am]+1)*sizeof(PetscInt),&uj);CHKERRQ(ierr);
2551     ierr = PetscFreeSpaceContiguous_Cholesky(&free_space,uj,am,ui,udiag);CHKERRQ(ierr); /* store matrix factor  */
2552     ierr = PetscIncompleteLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
2553     ierr = PetscFreeSpaceDestroy(free_space_lvl);CHKERRQ(ierr);
2554 
2555   } /* end of case: levels>0 || (levels=0 && !perm_identity) */
2556 
2557   /* put together the new matrix in MATSEQSBAIJ format */
2558   b    = (Mat_SeqSBAIJ*)(fact)->data;
2559   b->singlemalloc = PETSC_FALSE;
2560   ierr = PetscMalloc((ui[am]+1)*sizeof(MatScalar),&b->a);CHKERRQ(ierr);
2561   b->j    = uj;
2562   b->i    = ui;
2563   b->diag = udiag;
2564   b->free_diag = PETSC_TRUE;
2565   b->ilen = 0;
2566   b->imax = 0;
2567   b->row  = perm;
2568   b->col  = perm;
2569   ierr    = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr);
2570   ierr    = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr);
2571   b->icol = iperm;
2572   b->pivotinblocks = PETSC_FALSE; /* need to get from MatFactorInfo */
2573   ierr = PetscMalloc((am+1)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
2574   ierr = PetscLogObjectMemory(fact,ui[am]*(sizeof(PetscInt)+sizeof(MatScalar)));CHKERRQ(ierr);
2575   b->maxnz   = b->nz = ui[am];
2576   b->free_a  = PETSC_TRUE;
2577   b->free_ij = PETSC_TRUE;
2578 
2579   fact->info.factor_mallocs    = reallocs;
2580   fact->info.fill_ratio_given  = fill;
2581   if (ai[am] != 0) {
2582     fact->info.fill_ratio_needed = ((PetscReal)ui[am])/((PetscReal)ai[am]);
2583   } else {
2584     fact->info.fill_ratio_needed = 0.0;
2585   }
2586   fact->ops->choleskyfactornumeric = MatCholeskyFactorNumeric_SeqAIJ;
2587   PetscFunctionReturn(0);
2588 }
2589 
2590 #undef __FUNCT__
2591 #define __FUNCT__ "MatICCFactorSymbolic_SeqAIJ_inplace"
2592 PetscErrorCode MatICCFactorSymbolic_SeqAIJ_inplace(Mat fact,Mat A,IS perm,const MatFactorInfo *info)
2593 {
2594   Mat_SeqAIJ         *a = (Mat_SeqAIJ*)A->data;
2595   Mat_SeqSBAIJ       *b;
2596   PetscErrorCode     ierr;
2597   PetscTruth         perm_identity,missing;
2598   PetscInt           reallocs=0,i,*ai=a->i,*aj=a->j,am=A->rmap->n,*ui,*udiag;
2599   const PetscInt     *rip,*riip;
2600   PetscInt           jmin,jmax,nzk,k,j,*jl,prow,*il,nextprow;
2601   PetscInt           nlnk,*lnk,*lnk_lvl=PETSC_NULL,d;
2602   PetscInt           ncols,ncols_upper,*cols,*ajtmp,*uj,**uj_ptr,**uj_lvl_ptr;
2603   PetscReal          fill=info->fill,levels=info->levels;
2604   PetscFreeSpaceList free_space=PETSC_NULL,current_space=PETSC_NULL;
2605   PetscFreeSpaceList free_space_lvl=PETSC_NULL,current_space_lvl=PETSC_NULL;
2606   PetscBT            lnkbt;
2607   IS                 iperm;
2608 
2609   PetscFunctionBegin;
2610   if (A->rmap->n != A->cmap->n) SETERRQ2(PETSC_ERR_ARG_WRONG,"Must be square matrix, rows %D columns %D",A->rmap->n,A->cmap->n);
2611   ierr = MatMissingDiagonal(A,&missing,&d);CHKERRQ(ierr);
2612   if (missing) SETERRQ1(PETSC_ERR_ARG_WRONGSTATE,"Matrix is missing diagonal entry %D",d);
2613   ierr = ISIdentity(perm,&perm_identity);CHKERRQ(ierr);
2614   ierr = ISInvertPermutation(perm,PETSC_DECIDE,&iperm);CHKERRQ(ierr);
2615 
2616   ierr = PetscMalloc((am+1)*sizeof(PetscInt),&ui);CHKERRQ(ierr);
2617   ierr = PetscMalloc((am+1)*sizeof(PetscInt),&udiag);CHKERRQ(ierr);
2618   ui[0] = 0;
2619 
2620   /* ICC(0) without matrix ordering: simply copies fill pattern */
2621   if (!levels && perm_identity) {
2622 
2623     for (i=0; i<am; i++) {
2624       ui[i+1]  = ui[i] + ai[i+1] - a->diag[i];
2625       udiag[i] = ui[i];
2626     }
2627     ierr = PetscMalloc((ui[am]+1)*sizeof(PetscInt),&uj);CHKERRQ(ierr);
2628     cols = uj;
2629     for (i=0; i<am; i++) {
2630       aj    = a->j + a->diag[i];
2631       ncols = ui[i+1] - ui[i];
2632       for (j=0; j<ncols; j++) *cols++ = *aj++;
2633     }
2634   } else { /* case: levels>0 || (levels=0 && !perm_identity) */
2635     ierr = ISGetIndices(iperm,&riip);CHKERRQ(ierr);
2636     ierr = ISGetIndices(perm,&rip);CHKERRQ(ierr);
2637 
2638     /* initialization */
2639     ierr  = PetscMalloc((am+1)*sizeof(PetscInt),&ajtmp);CHKERRQ(ierr);
2640 
2641     /* jl: linked list for storing indices of the pivot rows
2642        il: il[i] points to the 1st nonzero entry of U(i,k:am-1) */
2643     ierr = PetscMalloc4(am,PetscInt*,&uj_ptr,am,PetscInt*,&uj_lvl_ptr,am,PetscInt,&jl,am,PetscInt,&il);CHKERRQ(ierr);
2644     for (i=0; i<am; i++){
2645       jl[i] = am; il[i] = 0;
2646     }
2647 
2648     /* create and initialize a linked list for storing column indices of the active row k */
2649     nlnk = am + 1;
2650     ierr = PetscIncompleteLLCreate(am,am,nlnk,lnk,lnk_lvl,lnkbt);CHKERRQ(ierr);
2651 
2652     /* initial FreeSpace size is fill*(ai[am]+1) */
2653     ierr = PetscFreeSpaceGet((PetscInt)(fill*(ai[am]+1)),&free_space);CHKERRQ(ierr);
2654     current_space = free_space;
2655     ierr = PetscFreeSpaceGet((PetscInt)(fill*(ai[am]+1)),&free_space_lvl);CHKERRQ(ierr);
2656     current_space_lvl = free_space_lvl;
2657 
2658     for (k=0; k<am; k++){  /* for each active row k */
2659       /* initialize lnk by the column indices of row rip[k] of A */
2660       nzk   = 0;
2661       ncols = ai[rip[k]+1] - ai[rip[k]];
2662       if (!ncols) SETERRQ2(PETSC_ERR_MAT_CH_ZRPVT,"Empty row in matrix: row in original ordering %D in permuted ordering %D",rip[k],k);
2663       ncols_upper = 0;
2664       for (j=0; j<ncols; j++){
2665         i = *(aj + ai[rip[k]] + j); /* unpermuted column index */
2666         if (riip[i] >= k){ /* only take upper triangular entry */
2667           ajtmp[ncols_upper] = i;
2668           ncols_upper++;
2669         }
2670       }
2671       ierr = PetscIncompleteLLInit(ncols_upper,ajtmp,am,riip,nlnk,lnk,lnk_lvl,lnkbt);CHKERRQ(ierr);
2672       nzk += nlnk;
2673 
2674       /* update lnk by computing fill-in for each pivot row to be merged in */
2675       prow = jl[k]; /* 1st pivot row */
2676 
2677       while (prow < k){
2678         nextprow = jl[prow];
2679 
2680         /* merge prow into k-th row */
2681         jmin = il[prow] + 1;  /* index of the 2nd nzero entry in U(prow,k:am-1) */
2682         jmax = ui[prow+1];
2683         ncols = jmax-jmin;
2684         i     = jmin - ui[prow];
2685         cols  = uj_ptr[prow] + i; /* points to the 2nd nzero entry in U(prow,k:am-1) */
2686         uj    = uj_lvl_ptr[prow] + i; /* levels of cols */
2687         j     = *(uj - 1);
2688         ierr = PetscICCLLAddSorted(ncols,cols,levels,uj,am,nlnk,lnk,lnk_lvl,lnkbt,j);CHKERRQ(ierr);
2689         nzk += nlnk;
2690 
2691         /* update il and jl for prow */
2692         if (jmin < jmax){
2693           il[prow] = jmin;
2694           j = *cols; jl[prow] = jl[j]; jl[j] = prow;
2695         }
2696         prow = nextprow;
2697       }
2698 
2699       /* if free space is not available, make more free space */
2700       if (current_space->local_remaining<nzk) {
2701         i = am - k + 1; /* num of unfactored rows */
2702         i *= PetscMin(nzk, (i-1)); /* i*nzk, i*(i-1): estimated and max additional space needed */
2703         ierr = PetscFreeSpaceGet(i,&current_space);CHKERRQ(ierr);
2704         ierr = PetscFreeSpaceGet(i,&current_space_lvl);CHKERRQ(ierr);
2705         reallocs++;
2706       }
2707 
2708       /* copy data into free_space and free_space_lvl, then initialize lnk */
2709       if (nzk == 0) SETERRQ1(PETSC_ERR_ARG_WRONG,"Empty row %D in ICC matrix factor",k);
2710       ierr = PetscIncompleteLLClean(am,am,nzk,lnk,lnk_lvl,current_space->array,current_space_lvl->array,lnkbt);CHKERRQ(ierr);
2711 
2712       /* add the k-th row into il and jl */
2713       if (nzk > 1){
2714         i = current_space->array[1]; /* col value of the first nonzero element in U(k, k+1:am-1) */
2715         jl[k] = jl[i]; jl[i] = k;
2716         il[k] = ui[k] + 1;
2717       }
2718       uj_ptr[k]     = current_space->array;
2719       uj_lvl_ptr[k] = current_space_lvl->array;
2720 
2721       current_space->array           += nzk;
2722       current_space->local_used      += nzk;
2723       current_space->local_remaining -= nzk;
2724 
2725       current_space_lvl->array           += nzk;
2726       current_space_lvl->local_used      += nzk;
2727       current_space_lvl->local_remaining -= nzk;
2728 
2729       ui[k+1] = ui[k] + nzk;
2730     }
2731 
2732 #if defined(PETSC_USE_INFO)
2733     if (ai[am] != 0) {
2734       PetscReal af = (PetscReal)ui[am]/((PetscReal)ai[am]);
2735       ierr = PetscInfo3(A,"Reallocs %D Fill ratio:given %G needed %G\n",reallocs,fill,af);CHKERRQ(ierr);
2736       ierr = PetscInfo1(A,"Run with -pc_factor_fill %G or use \n",af);CHKERRQ(ierr);
2737       ierr = PetscInfo1(A,"PCFactorSetFill(pc,%G) for best performance.\n",af);CHKERRQ(ierr);
2738     } else {
2739       ierr = PetscInfo(A,"Empty matrix.\n");CHKERRQ(ierr);
2740     }
2741 #endif
2742 
2743     ierr = ISRestoreIndices(perm,&rip);CHKERRQ(ierr);
2744     ierr = ISRestoreIndices(iperm,&riip);CHKERRQ(ierr);
2745     ierr = PetscFree4(uj_ptr,uj_lvl_ptr,jl,il);CHKERRQ(ierr);
2746     ierr = PetscFree(ajtmp);CHKERRQ(ierr);
2747 
2748     /* destroy list of free space and other temporary array(s) */
2749     ierr = PetscMalloc((ui[am]+1)*sizeof(PetscInt),&uj);CHKERRQ(ierr);
2750     ierr = PetscFreeSpaceContiguous(&free_space,uj);CHKERRQ(ierr);
2751     ierr = PetscIncompleteLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
2752     ierr = PetscFreeSpaceDestroy(free_space_lvl);CHKERRQ(ierr);
2753 
2754   } /* end of case: levels>0 || (levels=0 && !perm_identity) */
2755 
2756   /* put together the new matrix in MATSEQSBAIJ format */
2757 
2758   b    = (Mat_SeqSBAIJ*)fact->data;
2759   b->singlemalloc = PETSC_FALSE;
2760   ierr = PetscMalloc((ui[am]+1)*sizeof(MatScalar),&b->a);CHKERRQ(ierr);
2761   b->j    = uj;
2762   b->i    = ui;
2763   b->diag = udiag;
2764   b->free_diag = PETSC_TRUE;
2765   b->ilen = 0;
2766   b->imax = 0;
2767   b->row  = perm;
2768   b->col  = perm;
2769   ierr    = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr);
2770   ierr    = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr);
2771   b->icol = iperm;
2772   b->pivotinblocks = PETSC_FALSE; /* need to get from MatFactorInfo */
2773   ierr    = PetscMalloc((am+1)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
2774   ierr = PetscLogObjectMemory(fact,(ui[am]-am)*(sizeof(PetscInt)+sizeof(MatScalar)));CHKERRQ(ierr);
2775   b->maxnz   = b->nz = ui[am];
2776   b->free_a  = PETSC_TRUE;
2777   b->free_ij = PETSC_TRUE;
2778 
2779   fact->info.factor_mallocs    = reallocs;
2780   fact->info.fill_ratio_given  = fill;
2781   if (ai[am] != 0) {
2782     fact->info.fill_ratio_needed = ((PetscReal)ui[am])/((PetscReal)ai[am]);
2783   } else {
2784     fact->info.fill_ratio_needed = 0.0;
2785   }
2786   fact->ops->choleskyfactornumeric = MatCholeskyFactorNumeric_SeqAIJ_inplace;
2787   PetscFunctionReturn(0);
2788 }
2789 
2790 PetscErrorCode MatCholeskyFactorSymbolic_SeqAIJ(Mat fact,Mat A,IS perm,const MatFactorInfo *info)
2791 {
2792   Mat_SeqAIJ         *a = (Mat_SeqAIJ*)A->data;
2793   Mat_SeqSBAIJ       *b;
2794   PetscErrorCode     ierr;
2795   PetscTruth         perm_identity;
2796   PetscReal          fill = info->fill;
2797   const PetscInt     *rip,*riip;
2798   PetscInt           i,am=A->rmap->n,*ai=a->i,*aj=a->j,reallocs=0,prow;
2799   PetscInt           *jl,jmin,jmax,nzk,*ui,k,j,*il,nextprow;
2800   PetscInt           nlnk,*lnk,ncols,ncols_upper,*cols,*uj,**ui_ptr,*uj_ptr,*udiag;
2801   PetscFreeSpaceList free_space=PETSC_NULL,current_space=PETSC_NULL;
2802   PetscBT            lnkbt;
2803   IS                 iperm;
2804 
2805   PetscFunctionBegin;
2806   if (A->rmap->n != A->cmap->n) SETERRQ2(PETSC_ERR_ARG_WRONG,"Must be square matrix, rows %D columns %D",A->rmap->n,A->cmap->n);
2807   /* check whether perm is the identity mapping */
2808   ierr = ISIdentity(perm,&perm_identity);CHKERRQ(ierr);
2809   ierr = ISInvertPermutation(perm,PETSC_DECIDE,&iperm);CHKERRQ(ierr);
2810   ierr = ISGetIndices(iperm,&riip);CHKERRQ(ierr);
2811   ierr = ISGetIndices(perm,&rip);CHKERRQ(ierr);
2812 
2813   /* initialization */
2814   ierr  = PetscMalloc((am+1)*sizeof(PetscInt),&ui);CHKERRQ(ierr);
2815   ierr  = PetscMalloc((am+1)*sizeof(PetscInt),&udiag);CHKERRQ(ierr);
2816   ui[0] = 0;
2817 
2818   /* jl: linked list for storing indices of the pivot rows
2819      il: il[i] points to the 1st nonzero entry of U(i,k:am-1) */
2820   ierr = PetscMalloc4(am,PetscInt*,&ui_ptr,am,PetscInt,&jl,am,PetscInt,&il,am,PetscInt,&cols);CHKERRQ(ierr);
2821   for (i=0; i<am; i++){
2822     jl[i] = am; il[i] = 0;
2823   }
2824 
2825   /* create and initialize a linked list for storing column indices of the active row k */
2826   nlnk = am + 1;
2827   ierr = PetscLLCreate(am,am,nlnk,lnk,lnkbt);CHKERRQ(ierr);
2828 
2829   /* initial FreeSpace size is fill*(ai[am]+1) */
2830   ierr = PetscFreeSpaceGet((PetscInt)(fill*(ai[am]+1)),&free_space);CHKERRQ(ierr);
2831   current_space = free_space;
2832 
2833   for (k=0; k<am; k++){  /* for each active row k */
2834     /* initialize lnk by the column indices of row rip[k] of A */
2835     nzk   = 0;
2836     ncols = ai[rip[k]+1] - ai[rip[k]];
2837     if (!ncols) SETERRQ2(PETSC_ERR_MAT_CH_ZRPVT,"Empty row in matrix: row in original ordering %D in permuted ordering %D",rip[k],k);
2838     ncols_upper = 0;
2839     for (j=0; j<ncols; j++){
2840       i = riip[*(aj + ai[rip[k]] + j)];
2841       if (i >= k){ /* only take upper triangular entry */
2842         cols[ncols_upper] = i;
2843         ncols_upper++;
2844       }
2845     }
2846     ierr = PetscLLAdd(ncols_upper,cols,am,nlnk,lnk,lnkbt);CHKERRQ(ierr);
2847     nzk += nlnk;
2848 
2849     /* update lnk by computing fill-in for each pivot row to be merged in */
2850     prow = jl[k]; /* 1st pivot row */
2851 
2852     while (prow < k){
2853       nextprow = jl[prow];
2854       /* merge prow into k-th row */
2855       jmin = il[prow] + 1;  /* index of the 2nd nzero entry in U(prow,k:am-1) */
2856       jmax = ui[prow+1];
2857       ncols = jmax-jmin;
2858       uj_ptr = ui_ptr[prow] + jmin - ui[prow]; /* points to the 2nd nzero entry in U(prow,k:am-1) */
2859       ierr = PetscLLAddSorted(ncols,uj_ptr,am,nlnk,lnk,lnkbt);CHKERRQ(ierr);
2860       nzk += nlnk;
2861 
2862       /* update il and jl for prow */
2863       if (jmin < jmax){
2864         il[prow] = jmin;
2865         j = *uj_ptr; jl[prow] = jl[j]; jl[j] = prow;
2866       }
2867       prow = nextprow;
2868     }
2869 
2870     /* if free space is not available, make more free space */
2871     if (current_space->local_remaining<nzk) {
2872       i  = am - k + 1; /* num of unfactored rows */
2873       i *= PetscMin(nzk,i-1); /* i*nzk, i*(i-1): estimated and max additional space needed */
2874       ierr = PetscFreeSpaceGet(i,&current_space);CHKERRQ(ierr);
2875       reallocs++;
2876     }
2877 
2878     /* copy data into free space, then initialize lnk */
2879     ierr = PetscLLClean(am,am,nzk,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
2880 
2881     /* add the k-th row into il and jl */
2882     if (nzk > 1){
2883       i = current_space->array[1]; /* col value of the first nonzero element in U(k, k+1:am-1) */
2884       jl[k] = jl[i]; jl[i] = k;
2885       il[k] = ui[k] + 1;
2886     }
2887     ui_ptr[k] = current_space->array;
2888     current_space->array           += nzk;
2889     current_space->local_used      += nzk;
2890     current_space->local_remaining -= nzk;
2891 
2892     ui[k+1] = ui[k] + nzk;
2893   }
2894 
2895 #if defined(PETSC_USE_INFO)
2896   if (ai[am] != 0) {
2897     PetscReal af = (PetscReal)(ui[am])/((PetscReal)ai[am]);
2898     ierr = PetscInfo3(A,"Reallocs %D Fill ratio:given %G needed %G\n",reallocs,fill,af);CHKERRQ(ierr);
2899     ierr = PetscInfo1(A,"Run with -pc_factor_fill %G or use \n",af);CHKERRQ(ierr);
2900     ierr = PetscInfo1(A,"PCFactorSetFill(pc,%G) for best performance.\n",af);CHKERRQ(ierr);
2901   } else {
2902      ierr = PetscInfo(A,"Empty matrix.\n");CHKERRQ(ierr);
2903   }
2904 #endif
2905 
2906   ierr = ISRestoreIndices(perm,&rip);CHKERRQ(ierr);
2907   ierr = ISRestoreIndices(iperm,&riip);CHKERRQ(ierr);
2908   ierr = PetscFree4(ui_ptr,jl,il,cols);CHKERRQ(ierr);
2909 
2910   /* destroy list of free space and other temporary array(s) */
2911   ierr = PetscMalloc((ui[am]+1)*sizeof(PetscInt),&uj);CHKERRQ(ierr);
2912   ierr = PetscFreeSpaceContiguous_Cholesky(&free_space,uj,am,ui,udiag);CHKERRQ(ierr); /* store matrix factor */
2913   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
2914 
2915   /* put together the new matrix in MATSEQSBAIJ format */
2916 
2917   b = (Mat_SeqSBAIJ*)fact->data;
2918   b->singlemalloc = PETSC_FALSE;
2919   b->free_a       = PETSC_TRUE;
2920   b->free_ij      = PETSC_TRUE;
2921   ierr = PetscMalloc((ui[am]+1)*sizeof(MatScalar),&b->a);CHKERRQ(ierr);
2922   b->j    = uj;
2923   b->i    = ui;
2924   b->diag = udiag;
2925   b->free_diag = PETSC_TRUE;
2926   b->ilen = 0;
2927   b->imax = 0;
2928   b->row  = perm;
2929   b->col  = perm;
2930   ierr    = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr);
2931   ierr    = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr);
2932   b->icol = iperm;
2933   b->pivotinblocks = PETSC_FALSE; /* need to get from MatFactorInfo */
2934   ierr    = PetscMalloc((am+1)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
2935   ierr    = PetscLogObjectMemory(fact,ui[am]*(sizeof(PetscInt)+sizeof(MatScalar)));CHKERRQ(ierr);
2936   b->maxnz = b->nz = ui[am];
2937 
2938   fact->info.factor_mallocs    = reallocs;
2939   fact->info.fill_ratio_given  = fill;
2940   if (ai[am] != 0) {
2941     fact->info.fill_ratio_needed = ((PetscReal)ui[am])/((PetscReal)ai[am]);
2942   } else {
2943     fact->info.fill_ratio_needed = 0.0;
2944   }
2945   fact->ops->choleskyfactornumeric = MatCholeskyFactorNumeric_SeqAIJ;
2946   PetscFunctionReturn(0);
2947 }
2948 
2949 #undef __FUNCT__
2950 #define __FUNCT__ "MatCholeskyFactorSymbolic_SeqAIJ_inplace"
2951 PetscErrorCode MatCholeskyFactorSymbolic_SeqAIJ_inplace(Mat fact,Mat A,IS perm,const MatFactorInfo *info)
2952 {
2953   Mat_SeqAIJ         *a = (Mat_SeqAIJ*)A->data;
2954   Mat_SeqSBAIJ       *b;
2955   PetscErrorCode     ierr;
2956   PetscTruth         perm_identity;
2957   PetscReal          fill = info->fill;
2958   const PetscInt     *rip,*riip;
2959   PetscInt           i,am=A->rmap->n,*ai=a->i,*aj=a->j,reallocs=0,prow;
2960   PetscInt           *jl,jmin,jmax,nzk,*ui,k,j,*il,nextprow;
2961   PetscInt           nlnk,*lnk,ncols,ncols_upper,*cols,*uj,**ui_ptr,*uj_ptr;
2962   PetscFreeSpaceList free_space=PETSC_NULL,current_space=PETSC_NULL;
2963   PetscBT            lnkbt;
2964   IS                 iperm;
2965 
2966   PetscFunctionBegin;
2967   if (A->rmap->n != A->cmap->n) SETERRQ2(PETSC_ERR_ARG_WRONG,"Must be square matrix, rows %D columns %D",A->rmap->n,A->cmap->n);
2968   /* check whether perm is the identity mapping */
2969   ierr = ISIdentity(perm,&perm_identity);CHKERRQ(ierr);
2970   ierr = ISInvertPermutation(perm,PETSC_DECIDE,&iperm);CHKERRQ(ierr);
2971   ierr = ISGetIndices(iperm,&riip);CHKERRQ(ierr);
2972   ierr = ISGetIndices(perm,&rip);CHKERRQ(ierr);
2973 
2974   /* initialization */
2975   ierr  = PetscMalloc((am+1)*sizeof(PetscInt),&ui);CHKERRQ(ierr);
2976   ui[0] = 0;
2977 
2978   /* jl: linked list for storing indices of the pivot rows
2979      il: il[i] points to the 1st nonzero entry of U(i,k:am-1) */
2980   ierr = PetscMalloc4(am,PetscInt*,&ui_ptr,am,PetscInt,&jl,am,PetscInt,&il,am,PetscInt,&cols);CHKERRQ(ierr);
2981   for (i=0; i<am; i++){
2982     jl[i] = am; il[i] = 0;
2983   }
2984 
2985   /* create and initialize a linked list for storing column indices of the active row k */
2986   nlnk = am + 1;
2987   ierr = PetscLLCreate(am,am,nlnk,lnk,lnkbt);CHKERRQ(ierr);
2988 
2989   /* initial FreeSpace size is fill*(ai[am]+1) */
2990   ierr = PetscFreeSpaceGet((PetscInt)(fill*(ai[am]+1)),&free_space);CHKERRQ(ierr);
2991   current_space = free_space;
2992 
2993   for (k=0; k<am; k++){  /* for each active row k */
2994     /* initialize lnk by the column indices of row rip[k] of A */
2995     nzk   = 0;
2996     ncols = ai[rip[k]+1] - ai[rip[k]];
2997     if (!ncols) SETERRQ2(PETSC_ERR_MAT_CH_ZRPVT,"Empty row in matrix: row in original ordering %D in permuted ordering %D",rip[k],k);
2998     ncols_upper = 0;
2999     for (j=0; j<ncols; j++){
3000       i = riip[*(aj + ai[rip[k]] + j)];
3001       if (i >= k){ /* only take upper triangular entry */
3002         cols[ncols_upper] = i;
3003         ncols_upper++;
3004       }
3005     }
3006     ierr = PetscLLAdd(ncols_upper,cols,am,nlnk,lnk,lnkbt);CHKERRQ(ierr);
3007     nzk += nlnk;
3008 
3009     /* update lnk by computing fill-in for each pivot row to be merged in */
3010     prow = jl[k]; /* 1st pivot row */
3011 
3012     while (prow < k){
3013       nextprow = jl[prow];
3014       /* merge prow into k-th row */
3015       jmin = il[prow] + 1;  /* index of the 2nd nzero entry in U(prow,k:am-1) */
3016       jmax = ui[prow+1];
3017       ncols = jmax-jmin;
3018       uj_ptr = ui_ptr[prow] + jmin - ui[prow]; /* points to the 2nd nzero entry in U(prow,k:am-1) */
3019       ierr = PetscLLAddSorted(ncols,uj_ptr,am,nlnk,lnk,lnkbt);CHKERRQ(ierr);
3020       nzk += nlnk;
3021 
3022       /* update il and jl for prow */
3023       if (jmin < jmax){
3024         il[prow] = jmin;
3025         j = *uj_ptr; jl[prow] = jl[j]; jl[j] = prow;
3026       }
3027       prow = nextprow;
3028     }
3029 
3030     /* if free space is not available, make more free space */
3031     if (current_space->local_remaining<nzk) {
3032       i = am - k + 1; /* num of unfactored rows */
3033       i = PetscMin(i*nzk, i*(i-1)); /* i*nzk, i*(i-1): estimated and max additional space needed */
3034       ierr = PetscFreeSpaceGet(i,&current_space);CHKERRQ(ierr);
3035       reallocs++;
3036     }
3037 
3038     /* copy data into free space, then initialize lnk */
3039     ierr = PetscLLClean(am,am,nzk,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
3040 
3041     /* add the k-th row into il and jl */
3042     if (nzk-1 > 0){
3043       i = current_space->array[1]; /* col value of the first nonzero element in U(k, k+1:am-1) */
3044       jl[k] = jl[i]; jl[i] = k;
3045       il[k] = ui[k] + 1;
3046     }
3047     ui_ptr[k] = current_space->array;
3048     current_space->array           += nzk;
3049     current_space->local_used      += nzk;
3050     current_space->local_remaining -= nzk;
3051 
3052     ui[k+1] = ui[k] + nzk;
3053   }
3054 
3055 #if defined(PETSC_USE_INFO)
3056   if (ai[am] != 0) {
3057     PetscReal af = (PetscReal)(ui[am])/((PetscReal)ai[am]);
3058     ierr = PetscInfo3(A,"Reallocs %D Fill ratio:given %G needed %G\n",reallocs,fill,af);CHKERRQ(ierr);
3059     ierr = PetscInfo1(A,"Run with -pc_factor_fill %G or use \n",af);CHKERRQ(ierr);
3060     ierr = PetscInfo1(A,"PCFactorSetFill(pc,%G) for best performance.\n",af);CHKERRQ(ierr);
3061   } else {
3062      ierr = PetscInfo(A,"Empty matrix.\n");CHKERRQ(ierr);
3063   }
3064 #endif
3065 
3066   ierr = ISRestoreIndices(perm,&rip);CHKERRQ(ierr);
3067   ierr = ISRestoreIndices(iperm,&riip);CHKERRQ(ierr);
3068   ierr = PetscFree4(ui_ptr,jl,il,cols);CHKERRQ(ierr);
3069 
3070   /* destroy list of free space and other temporary array(s) */
3071   ierr = PetscMalloc((ui[am]+1)*sizeof(PetscInt),&uj);CHKERRQ(ierr);
3072   ierr = PetscFreeSpaceContiguous(&free_space,uj);CHKERRQ(ierr);
3073   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
3074 
3075   /* put together the new matrix in MATSEQSBAIJ format */
3076 
3077   b = (Mat_SeqSBAIJ*)fact->data;
3078   b->singlemalloc = PETSC_FALSE;
3079   b->free_a       = PETSC_TRUE;
3080   b->free_ij      = PETSC_TRUE;
3081   ierr = PetscMalloc((ui[am]+1)*sizeof(MatScalar),&b->a);CHKERRQ(ierr);
3082   b->j    = uj;
3083   b->i    = ui;
3084   b->diag = 0;
3085   b->ilen = 0;
3086   b->imax = 0;
3087   b->row  = perm;
3088   b->col  = perm;
3089   ierr    = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr);
3090   ierr    = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr);
3091   b->icol = iperm;
3092   b->pivotinblocks = PETSC_FALSE; /* need to get from MatFactorInfo */
3093   ierr    = PetscMalloc((am+1)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
3094   ierr    = PetscLogObjectMemory(fact,(ui[am]-am)*(sizeof(PetscInt)+sizeof(MatScalar)));CHKERRQ(ierr);
3095   b->maxnz = b->nz = ui[am];
3096 
3097   fact->info.factor_mallocs    = reallocs;
3098   fact->info.fill_ratio_given  = fill;
3099   if (ai[am] != 0) {
3100     fact->info.fill_ratio_needed = ((PetscReal)ui[am])/((PetscReal)ai[am]);
3101   } else {
3102     fact->info.fill_ratio_needed = 0.0;
3103   }
3104   fact->ops->choleskyfactornumeric = MatCholeskyFactorNumeric_SeqAIJ_inplace;
3105   PetscFunctionReturn(0);
3106 }
3107 
3108 #undef __FUNCT__
3109 #define __FUNCT__ "MatSolve_SeqAIJ_NaturalOrdering"
3110 PetscErrorCode MatSolve_SeqAIJ_NaturalOrdering(Mat A,Vec bb,Vec xx)
3111 {
3112   Mat_SeqAIJ        *a = (Mat_SeqAIJ*)A->data;
3113   PetscErrorCode    ierr;
3114   PetscInt          n = A->rmap->n;
3115   const PetscInt    *ai = a->i,*aj = a->j,*adiag = a->diag,*vi;
3116   PetscScalar       *x,sum;
3117   const PetscScalar *b;
3118   const MatScalar   *aa = a->a,*v;
3119   PetscInt          i,nz;
3120 
3121   PetscFunctionBegin;
3122   if (!n) PetscFunctionReturn(0);
3123 
3124   ierr = VecGetArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
3125   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
3126 
3127   /* forward solve the lower triangular */
3128   x[0] = b[0];
3129   v    = aa;
3130   vi   = aj;
3131   for (i=1; i<n; i++) {
3132     nz  = ai[i+1] - ai[i];
3133     sum = b[i];
3134     PetscSparseDenseMinusDot(sum,x,v,vi,nz);
3135     v  += nz;
3136     vi += nz;
3137     x[i] = sum;
3138   }
3139 
3140   /* backward solve the upper triangular */
3141   for (i=n-1; i>=0; i--){
3142     v   = aa + adiag[i+1] + 1;
3143     vi  = aj + adiag[i+1] + 1;
3144     nz = adiag[i] - adiag[i+1]-1;
3145     sum = x[i];
3146     PetscSparseDenseMinusDot(sum,x,v,vi,nz);
3147     x[i] = sum*v[nz]; /* x[i]=aa[adiag[i]]*sum; v++; */
3148   }
3149 
3150   ierr = PetscLogFlops(2.0*a->nz - A->cmap->n);CHKERRQ(ierr);
3151   ierr = VecRestoreArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
3152   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
3153   PetscFunctionReturn(0);
3154 }
3155 
3156 #undef __FUNCT__
3157 #define __FUNCT__ "MatSolve_SeqAIJ"
3158 PetscErrorCode MatSolve_SeqAIJ(Mat A,Vec bb,Vec xx)
3159 {
3160   Mat_SeqAIJ        *a = (Mat_SeqAIJ*)A->data;
3161   IS                iscol = a->col,isrow = a->row;
3162   PetscErrorCode    ierr;
3163   PetscInt          i,n=A->rmap->n,*vi,*ai=a->i,*aj=a->j,*adiag = a->diag,nz;
3164   const PetscInt    *rout,*cout,*r,*c;
3165   PetscScalar       *x,*tmp,sum;
3166   const PetscScalar *b;
3167   const MatScalar   *aa = a->a,*v;
3168 
3169   PetscFunctionBegin;
3170   if (!n) PetscFunctionReturn(0);
3171 
3172   ierr = VecGetArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
3173   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
3174   tmp  = a->solve_work;
3175 
3176   ierr = ISGetIndices(isrow,&rout);CHKERRQ(ierr); r = rout;
3177   ierr = ISGetIndices(iscol,&cout);CHKERRQ(ierr); c = cout;
3178 
3179   /* forward solve the lower triangular */
3180   tmp[0] = b[r[0]];
3181   v      = aa;
3182   vi     = aj;
3183   for (i=1; i<n; i++) {
3184     nz  = ai[i+1] - ai[i];
3185     sum = b[r[i]];
3186     PetscSparseDenseMinusDot(sum,tmp,v,vi,nz);
3187     tmp[i] = sum;
3188     v += nz; vi += nz;
3189   }
3190 
3191   /* backward solve the upper triangular */
3192   for (i=n-1; i>=0; i--){
3193     v   = aa + adiag[i+1]+1;
3194     vi  = aj + adiag[i+1]+1;
3195     nz  = adiag[i]-adiag[i+1]-1;
3196     sum = tmp[i];
3197     PetscSparseDenseMinusDot(sum,tmp,v,vi,nz);
3198     x[c[i]] = tmp[i] = sum*v[nz]; /* v[nz] = aa[adiag[i]] */
3199   }
3200 
3201   ierr = ISRestoreIndices(isrow,&rout);CHKERRQ(ierr);
3202   ierr = ISRestoreIndices(iscol,&cout);CHKERRQ(ierr);
3203   ierr = VecRestoreArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
3204   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
3205   ierr = PetscLogFlops(2*a->nz - A->cmap->n);CHKERRQ(ierr);
3206   PetscFunctionReturn(0);
3207 }
3208 
3209 #undef __FUNCT__
3210 #define __FUNCT__ "MatILUDTFactor_SeqAIJ"
3211 /*
3212     This will get a new name and become a varient of MatILUFactor_SeqAIJ() there is no longer seperate functions in the matrix function table for dt factors
3213 */
3214 PetscErrorCode MatILUDTFactor_SeqAIJ(Mat A,IS isrow,IS iscol,const MatFactorInfo *info,Mat *fact)
3215 {
3216   Mat                B = *fact;
3217   Mat_SeqAIJ         *a=(Mat_SeqAIJ*)A->data,*b;
3218   IS                 isicol;
3219   PetscErrorCode     ierr;
3220   const PetscInt     *r,*ic;
3221   PetscInt           i,n=A->rmap->n,*ai=a->i,*aj=a->j,*ajtmp,*adiag;
3222   PetscInt           *bi,*bj,*bdiag,*bdiag_rev;
3223   PetscInt           row,nzi,nzi_bl,nzi_bu,*im,nzi_al,nzi_au;
3224   PetscInt           nlnk,*lnk;
3225   PetscBT            lnkbt;
3226   PetscTruth         row_identity,icol_identity,both_identity;
3227   MatScalar          *aatmp,*pv,*batmp,*ba,*rtmp,*pc,multiplier,*vtmp,diag_tmp;
3228   const PetscInt     *ics;
3229   PetscInt           j,nz,*pj,*bjtmp,k,ncut,*jtmp;
3230   PetscReal          dt=info->dt,dtcol=info->dtcol,shift=info->shiftinblocks;
3231   PetscInt           dtcount=(PetscInt)info->dtcount,nnz_max;
3232   PetscTruth         missing;
3233 
3234   PetscFunctionBegin;
3235 
3236   if (dt      == PETSC_DEFAULT) dt      = 0.005;
3237   if (dtcol   == PETSC_DEFAULT) dtcol   = 0.01; /* XXX unused! */
3238   if (dtcount == PETSC_DEFAULT) dtcount = (PetscInt)(1.5*a->rmax);
3239 
3240   /* ------- symbolic factorization, can be reused ---------*/
3241   ierr = MatMissingDiagonal(A,&missing,&i);CHKERRQ(ierr);
3242   if (missing) SETERRQ1(PETSC_ERR_ARG_WRONGSTATE,"Matrix is missing diagonal entry %D",i);
3243   adiag=a->diag;
3244 
3245   ierr = ISInvertPermutation(iscol,PETSC_DECIDE,&isicol);CHKERRQ(ierr);
3246 
3247   /* bdiag is location of diagonal in factor */
3248   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bdiag);CHKERRQ(ierr);     /* becomes b->diag */
3249   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bdiag_rev);CHKERRQ(ierr); /* temporary */
3250 
3251   /* allocate row pointers bi */
3252   ierr = PetscMalloc((2*n+2)*sizeof(PetscInt),&bi);CHKERRQ(ierr);
3253 
3254   /* allocate bj and ba; max num of nonzero entries is (ai[n]+2*n*dtcount+2) */
3255   if (dtcount > n-1) dtcount = n-1; /* diagonal is excluded */
3256   nnz_max  = ai[n]+2*n*dtcount+2;
3257 
3258   ierr = PetscMalloc((nnz_max+1)*sizeof(PetscInt),&bj);CHKERRQ(ierr);
3259   ierr = PetscMalloc((nnz_max+1)*sizeof(MatScalar),&ba);CHKERRQ(ierr);
3260 
3261   /* put together the new matrix */
3262   ierr = MatSeqAIJSetPreallocation_SeqAIJ(B,MAT_SKIP_ALLOCATION,PETSC_NULL);CHKERRQ(ierr);
3263   ierr = PetscLogObjectParent(B,isicol);CHKERRQ(ierr);
3264   b    = (Mat_SeqAIJ*)B->data;
3265   b->free_a       = PETSC_TRUE;
3266   b->free_ij      = PETSC_TRUE;
3267   b->singlemalloc = PETSC_FALSE;
3268   b->a          = ba;
3269   b->j          = bj;
3270   b->i          = bi;
3271   b->diag       = bdiag;
3272   b->ilen       = 0;
3273   b->imax       = 0;
3274   b->row        = isrow;
3275   b->col        = iscol;
3276   ierr          = PetscObjectReference((PetscObject)isrow);CHKERRQ(ierr);
3277   ierr          = PetscObjectReference((PetscObject)iscol);CHKERRQ(ierr);
3278   b->icol       = isicol;
3279   ierr = PetscMalloc((n+1)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
3280 
3281   ierr = PetscLogObjectMemory(B,nnz_max*(sizeof(PetscInt)+sizeof(MatScalar)));CHKERRQ(ierr);
3282   b->maxnz = nnz_max;
3283 
3284   B->factor                = MAT_FACTOR_ILUDT;
3285   B->info.factor_mallocs   = 0;
3286   B->info.fill_ratio_given = ((PetscReal)nnz_max)/((PetscReal)ai[n]);
3287   CHKMEMQ;
3288   /* ------- end of symbolic factorization ---------*/
3289 
3290   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
3291   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
3292   ics  = ic;
3293 
3294   /* linked list for storing column indices of the active row */
3295   nlnk = n + 1;
3296   ierr = PetscLLCreate(n,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
3297 
3298   /* im: used by PetscLLAddSortedLU(); jtmp: working array for column indices of active row */
3299   ierr = PetscMalloc2(n,PetscInt,&im,n,PetscInt,&jtmp);CHKERRQ(ierr);
3300   /* rtmp, vtmp: working arrays for sparse and contiguous row entries of active row */
3301   ierr = PetscMalloc2(n,MatScalar,&rtmp,n,MatScalar,&vtmp);CHKERRQ(ierr);
3302   ierr = PetscMemzero(rtmp,n*sizeof(MatScalar));CHKERRQ(ierr);
3303 
3304   bi[0]    = 0;
3305   bdiag[0] = nnz_max-1; /* location of diag[0] in factor B */
3306   bdiag_rev[n] = bdiag[0];
3307   bi[2*n+1] = bdiag[0]+1; /* endof bj and ba array */
3308   for (i=0; i<n; i++) {
3309     /* copy initial fill into linked list */
3310     nzi = 0; /* nonzeros for active row i */
3311     nzi = ai[r[i]+1] - ai[r[i]];
3312     if (!nzi) SETERRQ2(PETSC_ERR_MAT_LU_ZRPVT,"Empty row in matrix: row in original ordering %D in permuted ordering %D",r[i],i);
3313     nzi_al = adiag[r[i]] - ai[r[i]];
3314     nzi_au = ai[r[i]+1] - adiag[r[i]] -1;
3315     ajtmp = aj + ai[r[i]];
3316     ierr = PetscLLAddPerm(nzi,ajtmp,ic,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
3317 
3318     /* load in initial (unfactored row) */
3319     aatmp = a->a + ai[r[i]];
3320     for (j=0; j<nzi; j++) {
3321       rtmp[ics[*ajtmp++]] = *aatmp++;
3322     }
3323 
3324     /* add pivot rows into linked list */
3325     row = lnk[n];
3326     while (row < i ) {
3327       nzi_bl = bi[row+1] - bi[row] + 1;
3328       bjtmp = bj + bdiag[row+1]+1; /* points to 1st column next to the diagonal in U */
3329       ierr  = PetscLLAddSortedLU(bjtmp,row,nlnk,lnk,lnkbt,i,nzi_bl,im);CHKERRQ(ierr);
3330       nzi  += nlnk;
3331       row   = lnk[row];
3332     }
3333 
3334     /* copy data from lnk into jtmp, then initialize lnk */
3335     ierr = PetscLLClean(n,n,nzi,lnk,jtmp,lnkbt);CHKERRQ(ierr);
3336 
3337     /* numerical factorization */
3338     bjtmp = jtmp;
3339     row   = *bjtmp++; /* 1st pivot row */
3340     while  ( row < i ) {
3341       pc         = rtmp + row;
3342       pv         = ba + bdiag[row]; /* 1./(diag of the pivot row) */
3343       multiplier = (*pc) * (*pv);
3344       *pc        = multiplier;
3345       if (PetscAbsScalar(*pc) > dt){ /* apply tolerance dropping rule */
3346         pj         = bj + bdiag[row+1] + 1; /* point to 1st entry of U(row,:) */
3347         pv         = ba + bdiag[row+1] + 1;
3348         /* if (multiplier < -1.0 or multiplier >1.0) printf("row/prow %d, %d, multiplier %g\n",i,row,multiplier); */
3349         nz         = bdiag[row] - bdiag[row+1] - 1; /* num of entries in U(row,:), excluding diagonal */
3350         for (j=0; j<nz; j++) rtmp[*pj++] -= multiplier * (*pv++);
3351         ierr = PetscLogFlops(2.0*nz);CHKERRQ(ierr);
3352       }
3353       row = *bjtmp++;
3354     }
3355 
3356     /* copy sparse rtmp into contiguous vtmp; separate L and U part */
3357     diag_tmp = rtmp[i];  /* save diagonal value - may not needed?? */
3358     nzi_bl = 0; j = 0;
3359     while (jtmp[j] < i){ /* Note: jtmp is sorted */
3360       vtmp[j] = rtmp[jtmp[j]]; rtmp[jtmp[j]]=0.0;
3361       nzi_bl++; j++;
3362     }
3363     nzi_bu = nzi - nzi_bl -1;
3364     while (j < nzi){
3365       vtmp[j] = rtmp[jtmp[j]]; rtmp[jtmp[j]]=0.0;
3366       j++;
3367     }
3368 
3369     bjtmp = bj + bi[i];
3370     batmp = ba + bi[i];
3371     /* apply level dropping rule to L part */
3372     ncut = nzi_al + dtcount;
3373     if (ncut < nzi_bl){
3374       ierr = PetscSortSplit(ncut,nzi_bl,vtmp,jtmp);CHKERRQ(ierr);
3375       ierr = PetscSortIntWithScalarArray(ncut,jtmp,vtmp);CHKERRQ(ierr);
3376     } else {
3377       ncut = nzi_bl;
3378     }
3379     for (j=0; j<ncut; j++){
3380       bjtmp[j] = jtmp[j];
3381       batmp[j] = vtmp[j];
3382       /* printf(" (%d,%g),",bjtmp[j],batmp[j]); */
3383     }
3384     bi[i+1] = bi[i] + ncut;
3385     nzi = ncut + 1;
3386 
3387     /* apply level dropping rule to U part */
3388     ncut = nzi_au + dtcount;
3389     if (ncut < nzi_bu){
3390       ierr = PetscSortSplit(ncut,nzi_bu,vtmp+nzi_bl+1,jtmp+nzi_bl+1);CHKERRQ(ierr);
3391       ierr = PetscSortIntWithScalarArray(ncut,jtmp+nzi_bl+1,vtmp+nzi_bl+1);CHKERRQ(ierr);
3392     } else {
3393       ncut = nzi_bu;
3394     }
3395     nzi += ncut;
3396 
3397     /* mark bdiagonal */
3398     bdiag[i+1]       = bdiag[i] - (ncut + 1);
3399     bdiag_rev[n-i-1] = bdiag[i+1];
3400     bi[2*n - i]      = bi[2*n - i +1] - (ncut + 1);
3401     bjtmp = bj + bdiag[i];
3402     batmp = ba + bdiag[i];
3403     *bjtmp = i;
3404     *batmp = diag_tmp; /* rtmp[i]; */
3405     if (*batmp == 0.0) {
3406       *batmp = dt+shift;
3407       /* printf(" row %d add shift %g\n",i,shift); */
3408     }
3409     *batmp = 1.0/(*batmp); /* invert diagonal entries for simplier triangular solves */
3410     /* printf(" (%d,%g),",*bjtmp,*batmp); */
3411 
3412     bjtmp = bj + bdiag[i+1]+1;
3413     batmp = ba + bdiag[i+1]+1;
3414     for (k=0; k<ncut; k++){
3415       bjtmp[k] = jtmp[nzi_bl+1+k];
3416       batmp[k] = vtmp[nzi_bl+1+k];
3417       /* printf(" (%d,%g),",bjtmp[k],batmp[k]); */
3418     }
3419     /* printf("\n"); */
3420 
3421     im[i]   = nzi; /* used by PetscLLAddSortedLU() */
3422     /*
3423     printf("row %d: bi %d, bdiag %d\n",i,bi[i],bdiag[i]);
3424     printf(" ----------------------------\n");
3425     */
3426   } /* for (i=0; i<n; i++) */
3427   /* printf("end of L %d, beginning of U %d\n",bi[n],bdiag[n]); */
3428   if (bi[n] >= bdiag[n]) SETERRQ2(PETSC_ERR_ARG_SIZ,"end of L array %d cannot >= the beginning of U array %d",bi[n],bdiag[n]);
3429 
3430   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
3431   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
3432 
3433   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
3434   ierr = PetscFree2(im,jtmp);CHKERRQ(ierr);
3435   ierr = PetscFree2(rtmp,vtmp);CHKERRQ(ierr);
3436   ierr = PetscFree(bdiag_rev);CHKERRQ(ierr);
3437 
3438   ierr = PetscLogFlops(B->cmap->n);CHKERRQ(ierr);
3439   b->maxnz = b->nz = bi[n] + bdiag[0] - bdiag[n];
3440 
3441   ierr = ISIdentity(isrow,&row_identity);CHKERRQ(ierr);
3442   ierr = ISIdentity(isicol,&icol_identity);CHKERRQ(ierr);
3443   both_identity = (PetscTruth) (row_identity && icol_identity);
3444   if (row_identity && icol_identity) {
3445     B->ops->solve = MatSolve_SeqAIJ_NaturalOrdering;
3446   } else {
3447     B->ops->solve = MatSolve_SeqAIJ;
3448   }
3449 
3450   B->ops->solveadd          = 0;
3451   B->ops->solvetranspose    = 0;
3452   B->ops->solvetransposeadd = 0;
3453   B->ops->matsolve          = 0;
3454   B->assembled              = PETSC_TRUE;
3455   B->preallocated           = PETSC_TRUE;
3456   PetscFunctionReturn(0);
3457 }
3458 
3459 /* a wraper of MatILUDTFactor_SeqAIJ() */
3460 #undef __FUNCT__
3461 #define __FUNCT__ "MatILUDTFactorSymbolic_SeqAIJ"
3462 /*
3463     This will get a new name and become a varient of MatILUFactor_SeqAIJ() there is no longer seperate functions in the matrix function table for dt factors
3464 */
3465 
3466 PetscErrorCode PETSCMAT_DLLEXPORT MatILUDTFactorSymbolic_SeqAIJ(Mat fact,Mat A,IS row,IS col,const MatFactorInfo *info)
3467 {
3468   PetscErrorCode     ierr;
3469 
3470   PetscFunctionBegin;
3471   ierr = MatILUDTFactor_SeqAIJ(A,row,col,info,&fact);CHKERRQ(ierr);
3472   PetscFunctionReturn(0);
3473 }
3474 
3475 /*
3476    same as MatLUFactorNumeric_SeqAIJ(), except using contiguous array matrix factors
3477    - intend to replace existing MatLUFactorNumeric_SeqAIJ()
3478 */
3479 #undef __FUNCT__
3480 #define __FUNCT__ "MatILUDTFactorNumeric_SeqAIJ"
3481 /*
3482     This will get a new name and become a varient of MatILUFactor_SeqAIJ() there is no longer seperate functions in the matrix function table for dt factors
3483 */
3484 
3485 PetscErrorCode PETSCMAT_DLLEXPORT MatILUDTFactorNumeric_SeqAIJ(Mat fact,Mat A,const MatFactorInfo *info)
3486 {
3487   Mat            C=fact;
3488   Mat_SeqAIJ     *a=(Mat_SeqAIJ*)A->data,*b=(Mat_SeqAIJ *)C->data;
3489   IS             isrow = b->row,isicol = b->icol;
3490   PetscErrorCode ierr;
3491   const PetscInt *r,*ic,*ics;
3492   PetscInt       i,j,k,n=A->rmap->n,*ai=a->i,*aj=a->j,*bi=b->i,*bj=b->j;
3493   PetscInt       *ajtmp,*bjtmp,nz,nzl,nzu,row,*bdiag = b->diag,*pj;
3494   MatScalar      *rtmp,*pc,multiplier,*v,*pv,*aa=a->a;
3495   PetscReal      dt=info->dt,shift=info->shiftinblocks;
3496   PetscTruth     row_identity, col_identity;
3497 
3498   PetscFunctionBegin;
3499   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
3500   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
3501   ierr = PetscMalloc((n+1)*sizeof(MatScalar),&rtmp);CHKERRQ(ierr);
3502   ics  = ic;
3503 
3504   for (i=0; i<n; i++){
3505     /* initialize rtmp array */
3506     nzl   = bi[i+1] - bi[i];       /* num of nozeros in L(i,:) */
3507     bjtmp = bj + bi[i];
3508     for  (j=0; j<nzl; j++) rtmp[*bjtmp++] = 0.0;
3509     rtmp[i] = 0.0;
3510     nzu   = bdiag[i] - bdiag[i+1]; /* num of nozeros in U(i,:) */
3511     bjtmp = bj + bdiag[i+1] + 1;
3512     for  (j=0; j<nzu; j++) rtmp[*bjtmp++] = 0.0;
3513 
3514     /* load in initial unfactored row of A */
3515     /* printf("row %d\n",i); */
3516     nz    = ai[r[i]+1] - ai[r[i]];
3517     ajtmp = aj + ai[r[i]];
3518     v     = aa + ai[r[i]];
3519     for (j=0; j<nz; j++) {
3520       rtmp[ics[*ajtmp++]] = v[j];
3521       /* printf(" (%d,%g),",ics[ajtmp[j]],rtmp[ics[ajtmp[j]]]); */
3522     }
3523     /* printf("\n"); */
3524 
3525     /* numerical factorization */
3526     bjtmp = bj + bi[i]; /* point to 1st entry of L(i,:) */
3527     nzl   = bi[i+1] - bi[i]; /* num of entries in L(i,:) */
3528     k = 0;
3529     while (k < nzl){
3530       row   = *bjtmp++;
3531       /* printf("  prow %d\n",row); */
3532       pc         = rtmp + row;
3533       pv         = b->a + bdiag[row]; /* 1./(diag of the pivot row) */
3534       multiplier = (*pc) * (*pv);
3535       *pc        = multiplier;
3536       if (PetscAbsScalar(multiplier) > dt){
3537         pj         = bj + bdiag[row+1] + 1; /* point to 1st entry of U(row,:) */
3538         pv         = b->a + bdiag[row+1] + 1;
3539         nz         = bdiag[row] - bdiag[row+1] - 1; /* num of entries in U(row,:), excluding diagonal */
3540         for (j=0; j<nz; j++) rtmp[*pj++] -= multiplier * (*pv++);
3541         /* ierr = PetscLogFlops(2.0*nz);CHKERRQ(ierr); */
3542       }
3543       k++;
3544     }
3545 
3546     /* finished row so stick it into b->a */
3547     /* L-part */
3548     pv = b->a + bi[i] ;
3549     pj = bj + bi[i] ;
3550     nzl = bi[i+1] - bi[i];
3551     for (j=0; j<nzl; j++) {
3552       pv[j] = rtmp[pj[j]];
3553       /* printf(" (%d,%g),",pj[j],pv[j]); */
3554     }
3555 
3556     /* diagonal: invert diagonal entries for simplier triangular solves */
3557     if (rtmp[i] == 0.0) rtmp[i] = dt+shift;
3558     b->a[bdiag[i]] = 1.0/rtmp[i];
3559     /* printf(" (%d,%g),",i,b->a[bdiag[i]]); */
3560 
3561     /* U-part */
3562     pv = b->a + bdiag[i+1] + 1;
3563     pj = bj + bdiag[i+1] + 1;
3564     nzu = bdiag[i] - bdiag[i+1] - 1;
3565     for (j=0; j<nzu; j++) {
3566       pv[j] = rtmp[pj[j]];
3567       /* printf(" (%d,%g),",pj[j],pv[j]); */
3568     }
3569     /* printf("\n"); */
3570   }
3571 
3572   ierr = PetscFree(rtmp);CHKERRQ(ierr);
3573   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
3574   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
3575 
3576   ierr = ISIdentity(isrow,&row_identity);CHKERRQ(ierr);
3577   ierr = ISIdentity(isicol,&col_identity);CHKERRQ(ierr);
3578   if (row_identity && col_identity) {
3579     C->ops->solve   = MatSolve_SeqAIJ_NaturalOrdering;
3580   } else {
3581     C->ops->solve   = MatSolve_SeqAIJ;
3582   }
3583   C->ops->solveadd           = 0;
3584   C->ops->solvetranspose     = 0;
3585   C->ops->solvetransposeadd  = 0;
3586   C->ops->matsolve           = 0;
3587   C->assembled    = PETSC_TRUE;
3588   C->preallocated = PETSC_TRUE;
3589   ierr = PetscLogFlops(C->cmap->n);CHKERRQ(ierr);
3590   PetscFunctionReturn(0);
3591 }
3592