xref: /petsc/src/mat/impls/aij/mpi/fdmpiaij.c (revision 7254ec97105973f9b37f4e9ed87aff1391a4a644)
1 
2 #include <../src/mat/impls/aij/mpi/mpiaij.h>
3 
4 extern PetscErrorCode MatCreateColmap_MPIAIJ_Private(Mat);
5 
6 #undef __FUNCT__
7 #define __FUNCT__ "MatFDColoringApply_MPIAIJ"
8 PetscErrorCode  MatFDColoringApply_MPIAIJ(Mat J,MatFDColoring coloring,Vec x1,MatStructure *flag,void *sctx)
9 {
10   PetscErrorCode (*f)(void*,Vec,Vec,void*) = (PetscErrorCode (*)(void*,Vec,Vec,void*))coloring->f;
11   PetscErrorCode ierr;
12   PetscInt       k,start,end,l,row,col,colb,**columnsforrow=coloring->columnsforrow,nz;
13   PetscScalar    dx,*y,*xx,*w3_array;
14   PetscScalar    *vscale_array;
15   PetscReal      epsilon = coloring->error_rel,umin = coloring->umin,unorm;
16   Vec            w1      = coloring->w1,w2=coloring->w2,w3;
17   void           *fctx   = coloring->fctx;
18   PetscBool      flg     = PETSC_FALSE;
19   PetscInt       ctype   = coloring->ctype,nxloc;
20   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)J->data;
21   Mat            A=aij->A,B=aij->B;
22   Mat_SeqAIJ     *cspA=(Mat_SeqAIJ*)A->data, *cspB=(Mat_SeqAIJ*)B->data;
23   PetscMPIInt    rank;
24   MatEntry       *Jentry=coloring->matentry;
25 
26   PetscFunctionBegin;
27   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)J), &rank);CHKERRQ(ierr);
28   ierr = MatSetUnfactored(J);CHKERRQ(ierr);
29   ierr = PetscOptionsGetBool(NULL,"-mat_fd_coloring_dont_rezero",&flg,NULL);CHKERRQ(ierr);
30   if (flg) {
31     ierr = PetscInfo(coloring,"Not calling MatZeroEntries()\n");CHKERRQ(ierr);
32   } else {
33     PetscBool assembled;
34     ierr = MatAssembled(J,&assembled);CHKERRQ(ierr);
35     if (assembled) {
36       ierr = MatZeroEntries(J);CHKERRQ(ierr);
37     }
38   }
39 
40   if (!coloring->vscale) { //ctype == IS_COLORING_GHOSTED ?
41     printf("[%d] create a non-ghostedcoloring->vscale\n",rank);
42     ierr = VecDuplicate(x1,&coloring->vscale);CHKERRQ(ierr);
43     //SETERRQ(PetscObjectComm((PetscObject)J),PETSC_ERR_ARG_NULL,"Null Object: coloring->scale");
44   }
45 
46   /* Set w1 = F(x1) */
47   if (!coloring->fset) {
48     ierr = PetscLogEventBegin(MAT_FDColoringFunction,0,0,0,0);CHKERRQ(ierr);
49     ierr = (*f)(sctx,x1,w1,fctx);CHKERRQ(ierr);
50     ierr = PetscLogEventEnd(MAT_FDColoringFunction,0,0,0,0);CHKERRQ(ierr);
51   } else {
52     coloring->fset = PETSC_FALSE;
53   }
54 
55   if (!coloring->w3) {
56     ierr = VecDuplicate(x1,&coloring->w3);CHKERRQ(ierr);
57     ierr = PetscLogObjectParent((PetscObject)coloring,(PetscObject)coloring->w3);CHKERRQ(ierr);
58   }
59   w3 = coloring->w3;
60 
61   /* Compute vscale = 1./dx - the local scale factors, including ghost points */
62   ierr = VecGetOwnershipRange(w1,&start,&end);CHKERRQ(ierr); /* =J's row ownershipRange, used by ghosted x! */
63   //printf("[%d] start end %d %d\n",rank,start,end);
64 
65   if (coloring->htype[0] == 'w') {
66     /* tacky test; need to make systematic if we add other approaches to computing h*/
67     ierr = VecNorm(x1,NORM_2,&unorm);CHKERRQ(ierr);
68     dx = 1.0/((1.0 + unorm)*epsilon);
69     ierr = VecSet(coloring->vscale,dx);CHKERRQ(ierr);
70   } else {
71     ierr = VecGetLocalSize(x1,&nxloc);CHKERRQ(ierr);
72     ierr = VecGetArray(x1,&xx);CHKERRQ(ierr);
73     ierr = VecGetArray(coloring->vscale,&vscale_array);CHKERRQ(ierr);
74     for (col=0; col<nxloc; col++) {
75       dx = xx[col];
76       if (PetscAbsScalar(dx) < umin) {
77         if (PetscRealPart(dx) >= 0.0)      dx = umin;
78         else if (PetscRealPart(dx) < 0.0 ) dx = -umin;
79       }
80       dx               *= epsilon;
81       vscale_array[col] = 1.0/dx;
82     }
83     ierr = VecRestoreArray(x1,&xx);CHKERRQ(ierr);
84     ierr = VecRestoreArray(coloring->vscale,&vscale_array);CHKERRQ(ierr);
85   }
86   if (ctype == IS_COLORING_GLOBAL) {
87     ierr = VecGhostUpdateBegin(coloring->vscale,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
88     ierr = VecGhostUpdateEnd(coloring->vscale,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
89   }
90 
91   /* Loop over each color */
92   nz = 0;
93   ierr = VecGetArray(coloring->vscale,&vscale_array);CHKERRQ(ierr);
94   for (k=0; k<coloring->ncolors; k++) {
95     coloring->currentcolor = k;
96 
97     /*
98       Loop over each column associated with color
99       adding the perturbation to the vector w3 = x1 + dx.
100     */
101     ierr = VecCopy(x1,w3);CHKERRQ(ierr);
102     ierr = VecGetArray(w3,&w3_array);CHKERRQ(ierr);
103     if (ctype == IS_COLORING_GLOBAL) w3_array = w3_array - start;
104 
105     for (l=0; l<coloring->ncolumns[k]; l++) {
106       col = coloring->columns[k][l]; /* local column (in global index!) of the matrix we are probing for */
107       /* convert global col to local colb */
108       if (col >= start && col < end) {
109         colb = col-start;
110       } else {
111 #if defined(PETSC_USE_CTABLE)
112         ierr = PetscTableFind(aij->colmap,col+1,&colb);CHKERRQ(ierr);
113         colb--;
114 #else
115         colb = aij->colmap[col] - 1; /* local column index */
116 #endif
117         colb += end - start;
118       }
119       w3_array[col] += 1.0/vscale_array[colb];
120     }
121     if (ctype == IS_COLORING_GLOBAL) w3_array = w3_array + start;
122     ierr = VecRestoreArray(w3,&w3_array);CHKERRQ(ierr);
123 
124     /*
125       Evaluate function at w3 = x1 + dx (here dx is a vector of perturbations)
126                            w2 = F(x1 + dx) - F(x1)
127     */
128     ierr = PetscLogEventBegin(MAT_FDColoringFunction,0,0,0,0);CHKERRQ(ierr);
129     ierr = (*f)(sctx,w3,w2,fctx);CHKERRQ(ierr);
130     ierr = PetscLogEventEnd(MAT_FDColoringFunction,0,0,0,0);CHKERRQ(ierr);
131     ierr = VecAXPY(w2,-1.0,w1);CHKERRQ(ierr);
132 
133     /* Loop over rows of vector, putting results into Jacobian matrix */
134     ierr = VecGetArray(w2,&y);CHKERRQ(ierr);
135     for (l=0; l<coloring->nrows[k]; l++) {
136       row                     = Jentry[nz].row;   /* local row index */
137       *(Jentry[nz].valaddr)   = y[row]*vscale_array[Jentry[nz].col];
138       nz++;
139     }
140     ierr = VecRestoreArray(w2,&y);CHKERRQ(ierr);
141   } /* endof for each color */
142   if (nz != cspA->nz + cspB->nz) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"nz %d != mat->nz %d\n",nz,cspA->nz+cspB->nz);
143   ierr = MatAssemblyBegin(J,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
144   ierr = MatAssemblyEnd(J,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
145   ierr = VecRestoreArray(coloring->vscale,&vscale_array);CHKERRQ(ierr);
146 
147   coloring->currentcolor = -1;
148   PetscFunctionReturn(0);
149 }
150 
151 #undef __FUNCT__
152 #define __FUNCT__ "MatFDColoringCreate_MPIAIJ_new"
153 PetscErrorCode MatFDColoringCreate_MPIAIJ_new(Mat mat,ISColoring iscoloring,MatFDColoring c)
154 {
155   Mat_MPIAIJ             *aij = (Mat_MPIAIJ*)mat->data;
156   PetscErrorCode         ierr;
157   PetscMPIInt            size,*ncolsonproc,*disp,nn;
158   PetscInt               i,n,nrows,j,k,m,ncols,col;
159   const PetscInt         *is,*A_ci,*A_cj,*B_ci,*B_cj,*row = NULL,*ltog=NULL;
160   PetscInt               nis = iscoloring->n,nctot,*cols;
161   PetscInt               *rowhit,cstart,cend,colb;
162   IS                     *isa;
163   ISLocalToGlobalMapping map = mat->cmap->mapping;
164   PetscInt               ctype=c->ctype;
165   Mat                    A=aij->A,B=aij->B;
166   Mat_SeqAIJ             *cspA=(Mat_SeqAIJ*)A->data, *cspB=(Mat_SeqAIJ*)B->data;
167   PetscScalar            *A_val=cspA->a,*B_val=cspB->a;
168   PetscInt               spidx;
169   PetscInt               *spidxA,*spidxB,nz;
170   PetscScalar            **valaddrhit;
171   MatEntry               *Jentry;
172 
173   PetscFunctionBegin;
174   if (ctype == IS_COLORING_GHOSTED) {
175     if(!map) SETERRQ(PetscObjectComm((PetscObject)mat),PETSC_ERR_ARG_INCOMP,"When using ghosted differencing matrix must have local to global mapping provided with MatSetLocalToGlobalMapping");
176     ierr = ISLocalToGlobalMappingGetIndices(map,&ltog);CHKERRQ(ierr);
177   }
178 
179   m         = mat->rmap->n;
180   cstart    = mat->cmap->rstart;
181   cend      = mat->cmap->rend;
182   c->M      = mat->rmap->N;         /* set the global rows and columns and local rows */
183   c->N      = mat->cmap->N;
184   c->m      = m;
185   c->rstart = mat->rmap->rstart;
186 
187   c->ncolors = nis;
188   ierr       = PetscMalloc(nis*sizeof(PetscInt),&c->ncolumns);CHKERRQ(ierr);
189   ierr       = PetscMalloc(nis*sizeof(PetscInt*),&c->columns);CHKERRQ(ierr);
190   ierr       = PetscMalloc(nis*sizeof(PetscInt),&c->nrows);CHKERRQ(ierr);
191   ierr       = PetscMalloc(nis*sizeof(PetscInt*),&c->rows);CHKERRQ(ierr);
192   ierr       = PetscMalloc(nis*sizeof(PetscInt*),&c->columnsforrow);CHKERRQ(ierr);
193   ierr       = PetscLogObjectMemory((PetscObject)c,5*nis*sizeof(PetscInt));CHKERRQ(ierr);
194 
195   nz         = cspA->nz + cspB->nz; /* total nonzero entries of mat */
196   ierr       = PetscMalloc(nz*sizeof(PetscScalar*),&c->valaddr);CHKERRQ(ierr);
197   ierr       = PetscMalloc(nz*sizeof(MatEntry),&Jentry);CHKERRQ(ierr);
198   ierr       = PetscLogObjectMemory((PetscObject)c,nz*sizeof(PetscScalar*));CHKERRQ(ierr);
199 
200   /* Allow access to data structures of local part of matrix
201    - creates aij->colmap which maps global column number to local number in part B */
202   if (!aij->colmap) {
203     ierr = MatCreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
204   }
205   ierr = MatGetColumnIJ_SeqAIJ_Color(aij->A,0,PETSC_FALSE,PETSC_FALSE,&ncols,&A_ci,&A_cj,&spidxA,NULL);CHKERRQ(ierr);
206   ierr = MatGetColumnIJ_SeqAIJ_Color(aij->B,0,PETSC_FALSE,PETSC_FALSE,&ncols,&B_ci,&B_cj,&spidxB,NULL);CHKERRQ(ierr);
207 
208   ierr = PetscMalloc2(m+1,PetscInt,&rowhit,m+1,PetscScalar*,&valaddrhit);CHKERRQ(ierr);
209   nz = 0;
210   ierr = ISColoringGetIS(iscoloring,PETSC_IGNORE,&isa);CHKERRQ(ierr);
211   for (i=0; i<nis; i++) { /* for each local color */
212     ierr = ISGetLocalSize(isa[i],&n);CHKERRQ(ierr);
213     ierr = ISGetIndices(isa[i],&is);CHKERRQ(ierr);
214 
215     c->ncolumns[i] = n; /* local number of columns of this color on this process */
216     if (n) {
217       ierr = PetscMalloc(n*sizeof(PetscInt),&c->columns[i]);CHKERRQ(ierr);
218       ierr = PetscLogObjectMemory((PetscObject)c,n*sizeof(PetscInt));CHKERRQ(ierr);
219       ierr = PetscMemcpy(c->columns[i],is,n*sizeof(PetscInt));CHKERRQ(ierr);
220     } else {
221       c->columns[i] = 0;
222     }
223 
224     if (ctype == IS_COLORING_GLOBAL) {
225       /* Determine nctot, the total (parallel) number of columns of this color */
226       ierr = MPI_Comm_size(PetscObjectComm((PetscObject)mat),&size);CHKERRQ(ierr);
227       ierr = PetscMalloc2(size,PetscMPIInt,&ncolsonproc,size,PetscMPIInt,&disp);CHKERRQ(ierr);
228 
229       /* ncolsonproc[j]: local ncolumns on proc[j] of this color */
230       ierr  = PetscMPIIntCast(n,&nn);CHKERRQ(ierr);
231       ierr  = MPI_Allgather(&nn,1,MPI_INT,ncolsonproc,1,MPI_INT,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
232       nctot = 0; for (j=0; j<size; j++) nctot += ncolsonproc[j];
233       if (!nctot) {
234         ierr = PetscInfo(mat,"Coloring of matrix has some unneeded colors with no corresponding rows\n");CHKERRQ(ierr);
235       }
236 
237       disp[0] = 0;
238       for (j=1; j<size; j++) {
239         disp[j] = disp[j-1] + ncolsonproc[j-1];
240       }
241 
242       /* Get cols, the complete list of columns for this color on each process */
243       ierr = PetscMalloc((nctot+1)*sizeof(PetscInt),&cols);CHKERRQ(ierr);
244       ierr = MPI_Allgatherv((void*)is,n,MPIU_INT,cols,ncolsonproc,disp,MPIU_INT,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
245       ierr = PetscFree2(ncolsonproc,disp);CHKERRQ(ierr);
246     } else if (ctype == IS_COLORING_GHOSTED) {
247       /* Determine local number of columns of this color on this process, including ghost points */
248       nctot = n;
249       ierr  = PetscMalloc((nctot+1)*sizeof(PetscInt),&cols);CHKERRQ(ierr);
250       ierr  = PetscMemcpy(cols,is,n*sizeof(PetscInt));CHKERRQ(ierr);
251     } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Not provided for this MatFDColoring type");
252 
253     /* Mark all rows affect by these columns */
254     ierr = PetscMemzero(rowhit,m*sizeof(PetscInt));CHKERRQ(ierr);
255     for (j=0; j<nctot; j++) { /* loop over columns*/
256       if (ctype == IS_COLORING_GHOSTED) {
257         col = ltog[cols[j]];
258       } else {
259         col = cols[j];
260       }
261       if (col >= cstart && col < cend) { /* column is in diagonal block of matrix A */
262         row = A_cj + A_ci[col-cstart];
263         nrows = A_ci[col-cstart+1] - A_ci[col-cstart];
264         /* loop over columns of A marking them in rowhit */
265         for (k=0; k<nrows; k++) {
266           /* set valaddrhit for part A */
267           spidx            = spidxA[A_ci[col-cstart] + k];
268           valaddrhit[*row] = &A_val[spidx];
269           rowhit[*row++]   = col - cstart + 1; /* local column index */
270         }
271       } else { /* column is in off-diagonal block of matrix B */
272 #if defined(PETSC_USE_CTABLE)
273         ierr = PetscTableFind(aij->colmap,col+1,&colb);CHKERRQ(ierr);
274         colb--;
275 #else
276         colb = aij->colmap[col] - 1; /* local column index */
277 #endif
278         if (colb == -1) {
279           nrows = 0;
280         } else {
281           row   = B_cj + B_ci[colb];
282           nrows = B_ci[colb+1] - B_ci[colb];
283         }
284         /* loop over columns of B marking them in rowhit */
285         for (k=0; k<nrows; k++) {
286           /* set valaddrhit for part B */
287           spidx            = spidxB[B_ci[colb] + k];
288           valaddrhit[*row] = &B_val[spidx];
289           rowhit[*row++]   = colb + 1 + cend - cstart; /* local column index */
290         }
291       }
292     }
293 
294     /* count the number of hits */
295     nrows = 0;
296     for (j=0; j<m; j++) {
297       if (rowhit[j]) nrows++;
298     }
299     c->nrows[i] = nrows;
300     ierr        = PetscMalloc((nrows+1)*sizeof(PetscInt),&c->rows[i]);CHKERRQ(ierr);
301     ierr        = PetscMalloc((nrows+1)*sizeof(PetscInt),&c->columnsforrow[i]);CHKERRQ(ierr);
302     ierr        = PetscLogObjectMemory((PetscObject)c,2*(nrows+1)*sizeof(PetscInt));CHKERRQ(ierr);
303     nrows       = 0;
304     for (j=0; j<m; j++) {
305       if (rowhit[j]) {
306         Jentry[nz].row             = j;              /* local row index */
307         Jentry[nz].col             = rowhit[j] - 1;  /* local column index */
308         Jentry[nz].valaddr         = valaddrhit[j];  /* address of mat value for this entry */
309 
310         c->rows[i][nrows]          = j;              /* local row index */
311         c->columnsforrow[i][nrows] = rowhit[j] - 1;  /* local column index */
312         c->valaddr[nz]             = valaddrhit[j];    /* address of mat value for this entry */
313         nz++;
314         nrows++;
315       }
316     }
317     ierr = PetscFree(cols);CHKERRQ(ierr);
318   }
319   if (nz != cspA->nz + cspB->nz) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"nz %d != mat->nz %d\n",nz,cspA->nz+cspB->nz);
320 
321   /* create vscale for storing dx */
322   if (ctype == IS_COLORING_GLOBAL) {
323     ierr = VecCreateGhost(PetscObjectComm((PetscObject)mat),m,PETSC_DETERMINE,B->cmap->n,aij->garray,&c->vscale);CHKERRQ(ierr);
324   }
325 
326   ierr = ISColoringRestoreIS(iscoloring,&isa);CHKERRQ(ierr);
327 
328   c->matentry = Jentry;
329   ierr = PetscFree2(rowhit,valaddrhit);CHKERRQ(ierr);
330   ierr = MatRestoreColumnIJ_SeqAIJ_Color(aij->A,0,PETSC_FALSE,PETSC_FALSE,&ncols,&A_ci,&A_cj,&spidxA,NULL);CHKERRQ(ierr);
331   ierr = MatRestoreColumnIJ_SeqAIJ_Color(aij->B,0,PETSC_FALSE,PETSC_FALSE,&ncols,&B_ci,&B_cj,&spidxB,NULL);CHKERRQ(ierr);
332   if (ctype == IS_COLORING_GHOSTED) {
333     ierr = ISLocalToGlobalMappingRestoreIndices(map,&ltog);CHKERRQ(ierr);
334   }
335 
336   mat->ops->fdcoloringapply = MatFDColoringApply_MPIAIJ;
337   PetscFunctionReturn(0);
338 }
339 
340 /*------------------------------------------------------*/
341 #undef __FUNCT__
342 #define __FUNCT__ "MatFDColoringCreate_MPIAIJ"
343 PetscErrorCode MatFDColoringCreate_MPIAIJ(Mat mat,ISColoring iscoloring,MatFDColoring c)
344 {
345   Mat_MPIAIJ             *aij = (Mat_MPIAIJ*)mat->data;
346   PetscErrorCode         ierr;
347   PetscMPIInt            size,*ncolsonproc,*disp,nn;
348   PetscInt               i,n,nrows,j,k,m,ncols,col;
349   const PetscInt         *is,*A_ci,*A_cj,*B_ci,*B_cj,*rows = 0,*ltog;
350   PetscInt               nis = iscoloring->n,nctot,*cols;
351   PetscInt               *rowhit,M,cstart,cend,colb;
352   PetscInt               *columnsforrow,l;
353   IS                     *isa;
354   PetscBool              done,flg;
355   ISLocalToGlobalMapping map   = mat->cmap->mapping;
356   PetscInt               ctype=c->ctype;
357   PetscBool              new_impl=PETSC_FALSE;
358 
359   PetscFunctionBegin;
360   ierr = PetscOptionsName("-new","using new impls","",&new_impl);CHKERRQ(ierr);
361   if (new_impl){
362     ierr =  MatFDColoringCreate_MPIAIJ_new(mat,iscoloring,c);CHKERRQ(ierr);
363     PetscFunctionReturn(0);
364   }
365   if (ctype == IS_COLORING_GHOSTED && !map) SETERRQ(PetscObjectComm((PetscObject)mat),PETSC_ERR_ARG_INCOMP,"When using ghosted differencing matrix must have local to global mapping provided with MatSetLocalToGlobalMapping");
366 
367   if (map) {ierr = ISLocalToGlobalMappingGetIndices(map,&ltog);CHKERRQ(ierr);}
368   else     ltog = NULL;
369   ierr = ISColoringGetIS(iscoloring,PETSC_IGNORE,&isa);CHKERRQ(ierr);
370 
371   M         = mat->rmap->n;
372   cstart    = mat->cmap->rstart;
373   cend      = mat->cmap->rend;
374   c->M      = mat->rmap->N;         /* set the global rows and columns and local rows */
375   c->N      = mat->cmap->N;
376   c->m      = mat->rmap->n;
377   c->rstart = mat->rmap->rstart;
378 
379   c->ncolors = nis;
380   ierr       = PetscMalloc(nis*sizeof(PetscInt),&c->ncolumns);CHKERRQ(ierr);
381   ierr       = PetscMalloc(nis*sizeof(PetscInt*),&c->columns);CHKERRQ(ierr);
382   ierr       = PetscMalloc(nis*sizeof(PetscInt),&c->nrows);CHKERRQ(ierr);
383   ierr       = PetscMalloc(nis*sizeof(PetscInt*),&c->rows);CHKERRQ(ierr);
384   ierr       = PetscMalloc(nis*sizeof(PetscInt*),&c->columnsforrow);CHKERRQ(ierr);
385   ierr       = PetscLogObjectMemory((PetscObject)c,5*nis*sizeof(PetscInt));CHKERRQ(ierr);
386 
387   /* Allow access to data structures of local part of matrix */
388   if (!aij->colmap) {
389     ierr = MatCreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
390   }
391   ierr = MatGetColumnIJ(aij->A,0,PETSC_FALSE,PETSC_FALSE,&ncols,&A_ci,&A_cj,&done);CHKERRQ(ierr);
392   ierr = MatGetColumnIJ(aij->B,0,PETSC_FALSE,PETSC_FALSE,&ncols,&B_ci,&B_cj,&done);CHKERRQ(ierr);
393 
394   ierr = PetscMalloc((M+1)*sizeof(PetscInt),&rowhit);CHKERRQ(ierr);
395   ierr = PetscMalloc((M+1)*sizeof(PetscInt),&columnsforrow);CHKERRQ(ierr);
396 
397   for (i=0; i<nis; i++) {
398     ierr = ISGetLocalSize(isa[i],&n);CHKERRQ(ierr);
399     ierr = ISGetIndices(isa[i],&is);CHKERRQ(ierr);
400 
401     c->ncolumns[i] = n; /* local number of columns of this color on this process */
402     if (n) {
403       ierr = PetscMalloc(n*sizeof(PetscInt),&c->columns[i]);CHKERRQ(ierr);
404       ierr = PetscLogObjectMemory((PetscObject)c,n*sizeof(PetscInt));CHKERRQ(ierr);
405       ierr = PetscMemcpy(c->columns[i],is,n*sizeof(PetscInt));CHKERRQ(ierr);
406     } else {
407       c->columns[i] = 0;
408     }
409 
410     if (ctype == IS_COLORING_GLOBAL) {
411       /* Determine the total (parallel) number of columns of this color */
412       ierr = MPI_Comm_size(PetscObjectComm((PetscObject)mat),&size);CHKERRQ(ierr);
413       ierr = PetscMalloc2(size,PetscMPIInt,&ncolsonproc,size,PetscMPIInt,&disp);CHKERRQ(ierr);
414 
415       ierr  = PetscMPIIntCast(n,&nn);CHKERRQ(ierr);
416       ierr  = MPI_Allgather(&nn,1,MPI_INT,ncolsonproc,1,MPI_INT,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
417       nctot = 0; for (j=0; j<size; j++) nctot += ncolsonproc[j];
418       if (!nctot) {
419         ierr = PetscInfo(mat,"Coloring of matrix has some unneeded colors with no corresponding rows\n");CHKERRQ(ierr);
420       }
421 
422       disp[0] = 0;
423       for (j=1; j<size; j++) {
424         disp[j] = disp[j-1] + ncolsonproc[j-1];
425       }
426 
427       /* Get complete list of columns for color on each processor */
428       ierr = PetscMalloc((nctot+1)*sizeof(PetscInt),&cols);CHKERRQ(ierr);
429       ierr = MPI_Allgatherv((void*)is,n,MPIU_INT,cols,ncolsonproc,disp,MPIU_INT,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
430       ierr = PetscFree2(ncolsonproc,disp);CHKERRQ(ierr);
431     } else if (ctype == IS_COLORING_GHOSTED) {
432       /* Determine local number of columns of this color on this process, including ghost points */
433       nctot = n;
434       ierr  = PetscMalloc((nctot+1)*sizeof(PetscInt),&cols);CHKERRQ(ierr);
435       ierr  = PetscMemcpy(cols,is,n*sizeof(PetscInt));CHKERRQ(ierr);
436     } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Not provided for this MatFDColoring type");
437 
438     /*
439        Mark all rows affect by these columns
440     */
441     /* Temporary option to allow for debugging/testing */
442     flg  = PETSC_FALSE;
443     ierr = PetscOptionsGetBool(NULL,"-matfdcoloring_slow",&flg,NULL);CHKERRQ(ierr);
444     if (!flg) { /*-----------------------------------------------------------------------------*/
445       /* crude, fast version */
446       ierr = PetscMemzero(rowhit,M*sizeof(PetscInt));CHKERRQ(ierr);
447       /* loop over columns*/
448       for (j=0; j<nctot; j++) {
449         if (ctype == IS_COLORING_GHOSTED) {
450           col = ltog[cols[j]];
451         } else {
452           col = cols[j];
453         }
454         if (col >= cstart && col < cend) {
455           /* column is in diagonal block of matrix */
456           rows = A_cj + A_ci[col-cstart];
457           m    = A_ci[col-cstart+1] - A_ci[col-cstart];
458         } else {
459 #if defined(PETSC_USE_CTABLE)
460           ierr = PetscTableFind(aij->colmap,col+1,&colb);CHKERRQ(ierr);
461           colb--;
462 #else
463           colb = aij->colmap[col] - 1;
464 #endif
465           if (colb == -1) {
466             m = 0;
467           } else {
468             rows = B_cj + B_ci[colb];
469             m    = B_ci[colb+1] - B_ci[colb];
470           }
471         }
472         /* loop over columns marking them in rowhit */
473         for (k=0; k<m; k++) {
474           rowhit[*rows++] = col + 1;
475         }
476       }
477 
478       /* count the number of hits */
479       nrows = 0;
480       for (j=0; j<M; j++) {
481         if (rowhit[j]) nrows++;
482       }
483       c->nrows[i] = nrows;
484       ierr        = PetscMalloc((nrows+1)*sizeof(PetscInt),&c->rows[i]);CHKERRQ(ierr);
485       ierr        = PetscMalloc((nrows+1)*sizeof(PetscInt),&c->columnsforrow[i]);CHKERRQ(ierr);
486       ierr        = PetscLogObjectMemory((PetscObject)c,2*(nrows+1)*sizeof(PetscInt));CHKERRQ(ierr);
487       nrows       = 0;
488       for (j=0; j<M; j++) {
489         if (rowhit[j]) {
490           c->rows[i][nrows]          = j;              /* local row index */
491           c->columnsforrow[i][nrows] = rowhit[j] - 1;  /* global column index */
492           nrows++;
493         }
494       }
495     } else { /*-------------------------------------------------------------------------------*/
496       /* slow version, using rowhit as a linked list */
497       PetscInt currentcol,fm,mfm;
498       rowhit[M] = M;
499       nrows     = 0;
500       /* loop over columns*/
501       for (j=0; j<nctot; j++) {
502         if (ctype == IS_COLORING_GHOSTED) {
503           col = ltog[cols[j]];
504         } else {
505           col = cols[j];
506         }
507         if (col >= cstart && col < cend) {
508           /* column is in diagonal block of matrix */
509           rows = A_cj + A_ci[col-cstart];
510           m    = A_ci[col-cstart+1] - A_ci[col-cstart];
511         } else {
512 #if defined(PETSC_USE_CTABLE)
513           ierr = PetscTableFind(aij->colmap,col+1,&colb);CHKERRQ(ierr);
514           colb--;
515 #else
516           colb = aij->colmap[col] - 1;
517 #endif
518           if (colb == -1) {
519             m = 0;
520           } else {
521             rows = B_cj + B_ci[colb];
522             m    = B_ci[colb+1] - B_ci[colb];
523           }
524         }
525 
526         /* loop over columns marking them in rowhit */
527         fm = M;    /* fm points to first entry in linked list */
528         for (k=0; k<m; k++) {
529           currentcol = *rows++;
530           /* is it already in the list? */
531           do {
532             mfm = fm;
533             fm  = rowhit[fm];
534           } while (fm < currentcol);
535           /* not in list so add it */
536           if (fm != currentcol) {
537             nrows++;
538             columnsforrow[currentcol] = col;
539             /* next three lines insert new entry into linked list */
540             rowhit[mfm]        = currentcol;
541             rowhit[currentcol] = fm;
542             fm                 = currentcol;
543             /* fm points to present position in list since we know the columns are sorted */
544           } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Invalid coloring of matrix detected");
545         }
546       }
547       c->nrows[i] = nrows;
548 
549       ierr = PetscMalloc((nrows+1)*sizeof(PetscInt),&c->rows[i]);CHKERRQ(ierr);
550       ierr = PetscMalloc((nrows+1)*sizeof(PetscInt),&c->columnsforrow[i]);CHKERRQ(ierr);
551       ierr = PetscLogObjectMemory((PetscObject)c,(nrows+1)*sizeof(PetscInt));CHKERRQ(ierr);
552       /* now store the linked list of rows into c->rows[i] */
553       nrows = 0;
554       fm    = rowhit[M];
555       do {
556         c->rows[i][nrows]            = fm;
557         c->columnsforrow[i][nrows++] = columnsforrow[fm];
558         fm                           = rowhit[fm];
559       } while (fm < M);
560     } /* ---------------------------------------------------------------------------------------*/
561     ierr = PetscFree(cols);CHKERRQ(ierr);
562   }
563 
564   /* Optimize by adding the vscale, and scaleforrow[][] fields */
565   /*
566        vscale will contain the "diagonal" on processor scalings followed by the off processor
567   */
568   if (ctype == IS_COLORING_GLOBAL) {
569     ierr = VecCreateGhost(PetscObjectComm((PetscObject)mat),aij->A->rmap->n,PETSC_DETERMINE,aij->B->cmap->n,aij->garray,&c->vscale);CHKERRQ(ierr);
570     ierr = PetscMalloc(c->ncolors*sizeof(PetscInt*),&c->vscaleforrow);CHKERRQ(ierr);
571     for (k=0; k<c->ncolors; k++) {
572       ierr = PetscMalloc((c->nrows[k]+1)*sizeof(PetscInt),&c->vscaleforrow[k]);CHKERRQ(ierr);
573       for (l=0; l<c->nrows[k]; l++) {
574         col = c->columnsforrow[k][l];
575         if (col >= cstart && col < cend) {
576           /* column is in diagonal block of matrix */
577           colb = col - cstart;
578         } else {
579           /* column  is in "off-processor" part */
580 #if defined(PETSC_USE_CTABLE)
581           ierr = PetscTableFind(aij->colmap,col+1,&colb);CHKERRQ(ierr);
582           colb--;
583 #else
584           colb = aij->colmap[col] - 1;
585 #endif
586           colb += cend - cstart;
587         }
588         c->vscaleforrow[k][l] = colb;
589       }
590     }
591   } else if (ctype == IS_COLORING_GHOSTED) {
592     /* Get gtol mapping */
593     PetscInt N = mat->cmap->N,nlocal,*gtol;
594     ierr = PetscMalloc((N+1)*sizeof(PetscInt),&gtol);CHKERRQ(ierr);
595     for (i=0; i<N; i++) gtol[i] = -1;
596     ierr = ISLocalToGlobalMappingGetSize(map,&nlocal);CHKERRQ(ierr);
597     for (i=0; i<nlocal; i++) gtol[ltog[i]] = i;
598 
599     c->vscale = 0; /* will be created in MatFDColoringApply() */
600     ierr      = PetscMalloc(c->ncolors*sizeof(PetscInt*),&c->vscaleforrow);CHKERRQ(ierr);
601     for (k=0; k<c->ncolors; k++) {
602       ierr = PetscMalloc((c->nrows[k]+1)*sizeof(PetscInt),&c->vscaleforrow[k]);CHKERRQ(ierr);
603       for (l=0; l<c->nrows[k]; l++) {
604         col = c->columnsforrow[k][l];      /* global column index */
605         c->vscaleforrow[k][l] = gtol[col]; /* local column index */
606       }
607     }
608     ierr = PetscFree(gtol);CHKERRQ(ierr);
609   }
610   ierr = ISColoringRestoreIS(iscoloring,&isa);CHKERRQ(ierr);
611 
612   ierr = PetscFree(rowhit);CHKERRQ(ierr);
613   ierr = PetscFree(columnsforrow);CHKERRQ(ierr);
614   ierr = MatRestoreColumnIJ(aij->A,0,PETSC_FALSE,PETSC_FALSE,&ncols,&A_ci,&A_cj,&done);CHKERRQ(ierr);
615   ierr = MatRestoreColumnIJ(aij->B,0,PETSC_FALSE,PETSC_FALSE,&ncols,&B_ci,&B_cj,&done);CHKERRQ(ierr);
616   if (map) {ierr = ISLocalToGlobalMappingRestoreIndices(map,&ltog);CHKERRQ(ierr);}
617   PetscFunctionReturn(0);
618 }
619 
620 
621 
622 
623 
624 
625