xref: /petsc/src/mat/impls/aij/seq/matptap.c (revision 18f873111d4b6eb34a7a3679fe2e9fdf652c10bd)
1 /*
2   Defines projective product routines where A is a SeqAIJ matrix
3           C = P^T * A * P
4 */
5 
6 #include "src/mat/impls/aij/seq/aij.h"   /*I "petscmat.h" I*/
7 #include "src/mat/utils/freespace.h"
8 #include "petscbt.h"
9 
10 
11 #undef __FUNCT__
12 #define __FUNCT__ "MatPtAP_SeqAIJ_SeqAIJ"
13 PetscErrorCode MatPtAP_SeqAIJ_SeqAIJ(Mat A,Mat P,MatReuse scall,PetscReal fill,Mat *C)
14 {
15   PetscErrorCode ierr;
16 
17   PetscFunctionBegin;
18   if (scall == MAT_INITIAL_MATRIX){
19     ierr = PetscLogEventBegin(MAT_PtAPSymbolic,A,P,0,0);CHKERRQ(ierr);
20     ierr = MatPtAPSymbolic_SeqAIJ_SeqAIJ(A,P,fill,C);CHKERRQ(ierr);
21     ierr = PetscLogEventEnd(MAT_PtAPSymbolic,A,P,0,0);CHKERRQ(ierr);
22   }
23   ierr = PetscLogEventBegin(MAT_PtAPNumeric,A,P,0,0);CHKERRQ(ierr);
24   ierr = MatPtAPNumeric_SeqAIJ_SeqAIJ(A,P,*C);CHKERRQ(ierr);
25   ierr = PetscLogEventEnd(MAT_PtAPNumeric,A,P,0,0);CHKERRQ(ierr);
26   PetscFunctionReturn(0);
27 }
28 
29 #undef __FUNCT__
30 #define __FUNCT__ "MatPtAPSymbolic_SeqAIJ_SeqAIJ"
31 PetscErrorCode MatPtAPSymbolic_SeqAIJ_SeqAIJ(Mat A,Mat P,PetscReal fill,Mat *C)
32 {
33   PetscErrorCode ierr;
34   FreeSpaceList  free_space=PETSC_NULL,current_space=PETSC_NULL;
35   Mat_SeqAIJ     *a = (Mat_SeqAIJ*)A->data,*p = (Mat_SeqAIJ*)P->data,*c;
36   PetscInt       *pti,*ptj,*ptJ,*ai=a->i,*aj=a->j,*ajj,*pi=p->i,*pj=p->j,*pjj;
37   PetscInt       *ci,*cj,*ptadenserow,*ptasparserow,*ptaj;
38   PetscInt       an=A->N,am=A->M,pn=P->N,pm=P->M;
39   PetscInt       i,j,k,ptnzi,arow,anzj,ptanzi,prow,pnzj,cnzi,nlnk,*lnk;
40   MatScalar      *ca;
41   PetscBT        lnkbt;
42 
43   PetscFunctionBegin;
44   /* Get ij structure of P^T */
45   ierr = MatGetSymbolicTranspose_SeqAIJ(P,&pti,&ptj);CHKERRQ(ierr);
46   ptJ=ptj;
47 
48   /* Allocate ci array, arrays for fill computation and */
49   /* free space for accumulating nonzero column info */
50   ierr = PetscMalloc((pn+1)*sizeof(PetscInt),&ci);CHKERRQ(ierr);
51   ci[0] = 0;
52 
53   ierr = PetscMalloc((2*an+1)*sizeof(PetscInt),&ptadenserow);CHKERRQ(ierr);
54   ierr = PetscMemzero(ptadenserow,(2*an+1)*sizeof(PetscInt));CHKERRQ(ierr);
55   ptasparserow = ptadenserow  + an;
56 
57   /* create and initialize a linked list */
58   nlnk = pn+1;
59   ierr = PetscLLCreate(pn,pn,nlnk,lnk,lnkbt);CHKERRQ(ierr);
60 
61   /* Set initial free space to be nnz(A) scaled by aspect ratio of P. */
62   /* This should be reasonable if sparsity of PtAP is similar to that of A. */
63   ierr          = GetMoreSpace((ai[am]/pm)*pn,&free_space);
64   current_space = free_space;
65 
66   /* Determine symbolic info for each row of C: */
67   for (i=0;i<pn;i++) {
68     ptnzi  = pti[i+1] - pti[i];
69     ptanzi = 0;
70     /* Determine symbolic row of PtA: */
71     for (j=0;j<ptnzi;j++) {
72       arow = *ptJ++;
73       anzj = ai[arow+1] - ai[arow];
74       ajj  = aj + ai[arow];
75       for (k=0;k<anzj;k++) {
76         if (!ptadenserow[ajj[k]]) {
77           ptadenserow[ajj[k]]    = -1;
78           ptasparserow[ptanzi++] = ajj[k];
79         }
80       }
81     }
82       /* Using symbolic info for row of PtA, determine symbolic info for row of C: */
83     ptaj = ptasparserow;
84     cnzi   = 0;
85     for (j=0;j<ptanzi;j++) {
86       prow = *ptaj++;
87       pnzj = pi[prow+1] - pi[prow];
88       pjj  = pj + pi[prow];
89       /* add non-zero cols of P into the sorted linked list lnk */
90       ierr = PetscLLAdd(pnzj,pjj,pn,nlnk,lnk,lnkbt);CHKERRQ(ierr);
91       cnzi += nlnk;
92     }
93 
94     /* If free space is not available, make more free space */
95     /* Double the amount of total space in the list */
96     if (current_space->local_remaining<cnzi) {
97       ierr = GetMoreSpace(current_space->total_array_size,&current_space);CHKERRQ(ierr);
98     }
99 
100     /* Copy data into free space, and zero out denserows */
101     ierr = PetscLLClean(pn,pn,cnzi,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
102     current_space->array           += cnzi;
103     current_space->local_used      += cnzi;
104     current_space->local_remaining -= cnzi;
105 
106     for (j=0;j<ptanzi;j++) {
107       ptadenserow[ptasparserow[j]] = 0;
108     }
109     /* Aside: Perhaps we should save the pta info for the numerical factorization. */
110     /*        For now, we will recompute what is needed. */
111     ci[i+1] = ci[i] + cnzi;
112   }
113   /* nnz is now stored in ci[ptm], column indices are in the list of free space */
114   /* Allocate space for cj, initialize cj, and */
115   /* destroy list of free space and other temporary array(s) */
116   ierr = PetscMalloc((ci[pn]+1)*sizeof(PetscInt),&cj);CHKERRQ(ierr);
117   ierr = MakeSpaceContiguous(&free_space,cj);CHKERRQ(ierr);
118   ierr = PetscFree(ptadenserow);CHKERRQ(ierr);
119   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
120 
121   /* Allocate space for ca */
122   ierr = PetscMalloc((ci[pn]+1)*sizeof(MatScalar),&ca);CHKERRQ(ierr);
123   ierr = PetscMemzero(ca,(ci[pn]+1)*sizeof(MatScalar));CHKERRQ(ierr);
124 
125   /* put together the new matrix */
126   ierr = MatCreateSeqAIJWithArrays(A->comm,pn,pn,ci,cj,ca,C);CHKERRQ(ierr);
127 
128   /* MatCreateSeqAIJWithArrays flags matrix so PETSc doesn't free the user's arrays. */
129   /* Since these are PETSc arrays, change flags to free them as necessary. */
130   c = (Mat_SeqAIJ *)((*C)->data);
131   c->freedata = PETSC_TRUE;
132   c->nonew    = 0;
133 
134   /* Clean up. */
135   ierr = MatRestoreSymbolicTranspose_SeqAIJ(P,&pti,&ptj);CHKERRQ(ierr);
136 
137   PetscFunctionReturn(0);
138 }
139 
140 #include "src/mat/impls/maij/maij.h"
141 #undef __FUNCT__
142 #define __FUNCT__ "MatPtAPSymbolic_SeqAIJ_SeqMAIJ"
143 PetscErrorCode MatPtAPSymbolic_SeqAIJ_SeqMAIJ(Mat A,Mat PP,PetscReal fill,Mat *C)
144 {
145   /* This routine requires testing -- but it's getting better. */
146   PetscErrorCode ierr;
147   FreeSpaceList  free_space=PETSC_NULL,current_space=PETSC_NULL;
148   Mat_SeqMAIJ    *pp=(Mat_SeqMAIJ*)PP->data;
149   Mat            P=pp->AIJ;
150   Mat_SeqAIJ     *a=(Mat_SeqAIJ*)A->data,*p=(Mat_SeqAIJ*)P->data,*c;
151   PetscInt       *pti,*ptj,*ptJ,*ai=a->i,*aj=a->j,*ajj,*pi=p->i,*pj=p->j,*pjj;
152   PetscInt       *ci,*cj,*ptadenserow,*ptasparserow,*denserow,*sparserow,*ptaj;
153   PetscInt       an=A->N,am=A->M,pn=P->N,pm=P->M,ppdof=pp->dof,cn;
154   PetscInt       i,j,k,dof,pshift,ptnzi,arow,anzj,ptanzi,prow,pnzj,cnzi;
155   MatScalar      *ca;
156 
157   PetscFunctionBegin;
158   /* Start timer */
159   ierr = PetscLogEventBegin(MAT_PtAPSymbolic,A,PP,0,0);CHKERRQ(ierr);
160 
161   /* Get ij structure of P^T */
162   ierr = MatGetSymbolicTranspose_SeqAIJ(P,&pti,&ptj);CHKERRQ(ierr);
163 
164   cn = pn*ppdof;
165   /* Allocate ci array, arrays for fill computation and */
166   /* free space for accumulating nonzero column info */
167   ierr = PetscMalloc((cn+1)*sizeof(PetscInt),&ci);CHKERRQ(ierr);
168   ci[0] = 0;
169 
170   /* Work arrays for rows of P^T*A */
171   ierr = PetscMalloc((2*cn+2*an+1)*sizeof(PetscInt),&ptadenserow);CHKERRQ(ierr);
172   ierr = PetscMemzero(ptadenserow,(2*cn+2*an+1)*sizeof(PetscInt));CHKERRQ(ierr);
173   ptasparserow = ptadenserow  + an;
174   denserow     = ptasparserow + an;
175   sparserow    = denserow     + cn;
176 
177   /* Set initial free space to be nnz(A) scaled by aspect ratio of P. */
178   /* This should be reasonable if sparsity of PtAP is similar to that of A. */
179   /* Note, aspect ratio of P is the same as the aspect ratio of SeqAIJ inside P */
180   ierr          = GetMoreSpace((ai[am]/pm)*pn,&free_space);
181   current_space = free_space;
182 
183   /* Determine symbolic info for each row of C: */
184   for (i=0;i<pn;i++) {
185     ptnzi  = pti[i+1] - pti[i];
186     ptJ    = ptj + pti[i];
187     for (dof=0;dof<ppdof;dof++) {
188       ptanzi = 0;
189       /* Determine symbolic row of PtA: */
190       for (j=0;j<ptnzi;j++) {
191         /* Expand ptJ[j] by block size and shift by dof to get the right row of A */
192         arow = ptJ[j]*ppdof + dof;
193         /* Nonzeros of P^T*A will be in same locations as any element of A in that row */
194         anzj = ai[arow+1] - ai[arow];
195         ajj  = aj + ai[arow];
196         for (k=0;k<anzj;k++) {
197           if (!ptadenserow[ajj[k]]) {
198             ptadenserow[ajj[k]]    = -1;
199             ptasparserow[ptanzi++] = ajj[k];
200           }
201         }
202       }
203       /* Using symbolic info for row of PtA, determine symbolic info for row of C: */
204       ptaj = ptasparserow;
205       cnzi   = 0;
206       for (j=0;j<ptanzi;j++) {
207         /* Get offset within block of P */
208         pshift = *ptaj%ppdof;
209         /* Get block row of P */
210         prow = (*ptaj++)/ppdof; /* integer division */
211         /* P has same number of nonzeros per row as the compressed form */
212         pnzj = pi[prow+1] - pi[prow];
213         pjj  = pj + pi[prow];
214         for (k=0;k<pnzj;k++) {
215           /* Locations in C are shifted by the offset within the block */
216           /* Note: we cannot use PetscLLAdd here because of the additional offset for the write location */
217           if (!denserow[pjj[k]*ppdof+pshift]) {
218             denserow[pjj[k]*ppdof+pshift] = -1;
219             sparserow[cnzi++]             = pjj[k]*ppdof+pshift;
220           }
221         }
222       }
223 
224       /* sort sparserow */
225       ierr = PetscSortInt(cnzi,sparserow);CHKERRQ(ierr);
226 
227       /* If free space is not available, make more free space */
228       /* Double the amount of total space in the list */
229       if (current_space->local_remaining<cnzi) {
230         ierr = GetMoreSpace(current_space->total_array_size,&current_space);CHKERRQ(ierr);
231       }
232 
233       /* Copy data into free space, and zero out denserows */
234       ierr = PetscMemcpy(current_space->array,sparserow,cnzi*sizeof(PetscInt));CHKERRQ(ierr);
235       current_space->array           += cnzi;
236       current_space->local_used      += cnzi;
237       current_space->local_remaining -= cnzi;
238 
239       for (j=0;j<ptanzi;j++) {
240         ptadenserow[ptasparserow[j]] = 0;
241       }
242       for (j=0;j<cnzi;j++) {
243         denserow[sparserow[j]] = 0;
244       }
245       /* Aside: Perhaps we should save the pta info for the numerical factorization. */
246       /*        For now, we will recompute what is needed. */
247       ci[i*ppdof+1+dof] = ci[i*ppdof+dof] + cnzi;
248     }
249   }
250   /* nnz is now stored in ci[ptm], column indices are in the list of free space */
251   /* Allocate space for cj, initialize cj, and */
252   /* destroy list of free space and other temporary array(s) */
253   ierr = PetscMalloc((ci[cn]+1)*sizeof(PetscInt),&cj);CHKERRQ(ierr);
254   ierr = MakeSpaceContiguous(&free_space,cj);CHKERRQ(ierr);
255   ierr = PetscFree(ptadenserow);CHKERRQ(ierr);
256 
257   /* Allocate space for ca */
258   ierr = PetscMalloc((ci[cn]+1)*sizeof(MatScalar),&ca);CHKERRQ(ierr);
259   ierr = PetscMemzero(ca,(ci[cn]+1)*sizeof(MatScalar));CHKERRQ(ierr);
260 
261   /* put together the new matrix */
262   ierr = MatCreateSeqAIJWithArrays(A->comm,cn,cn,ci,cj,ca,C);CHKERRQ(ierr);
263 
264   /* MatCreateSeqAIJWithArrays flags matrix so PETSc doesn't free the user's arrays. */
265   /* Since these are PETSc arrays, change flags to free them as necessary. */
266   c = (Mat_SeqAIJ *)((*C)->data);
267   c->freedata = PETSC_TRUE;
268   c->nonew    = 0;
269 
270   /* Clean up. */
271   ierr = MatRestoreSymbolicTranspose_SeqAIJ(P,&pti,&ptj);CHKERRQ(ierr);
272 
273   ierr = PetscLogEventEnd(MAT_PtAPSymbolic,A,PP,0,0);CHKERRQ(ierr);
274   PetscFunctionReturn(0);
275 }
276 
277 #undef __FUNCT__
278 #define __FUNCT__ "MatPtAPNumeric_SeqAIJ_SeqAIJ"
279 PetscErrorCode MatPtAPNumeric_SeqAIJ_SeqAIJ(Mat A,Mat P,Mat C)
280 {
281   PetscErrorCode ierr;
282   PetscInt       flops=0;
283   Mat_SeqAIJ     *a  = (Mat_SeqAIJ *) A->data;
284   Mat_SeqAIJ     *p  = (Mat_SeqAIJ *) P->data;
285   Mat_SeqAIJ     *c  = (Mat_SeqAIJ *) C->data;
286   PetscInt       *ai=a->i,*aj=a->j,*apj,*apjdense,*pi=p->i,*pj=p->j,*pJ=p->j,*pjj;
287   PetscInt       *ci=c->i,*cj=c->j,*cjj;
288   PetscInt       am=A->M,cn=C->N,cm=C->M;
289   PetscInt       i,j,k,anzi,pnzi,apnzj,nextap,pnzj,prow,crow;
290   MatScalar      *aa=a->a,*apa,*pa=p->a,*pA=p->a,*paj,*ca=c->a,*caj;
291 
292   PetscFunctionBegin;
293   /* Allocate temporary array for storage of one row of A*P */
294   ierr = PetscMalloc(cn*(sizeof(MatScalar)+2*sizeof(PetscInt)),&apa);CHKERRQ(ierr);
295   ierr = PetscMemzero(apa,cn*(sizeof(MatScalar)+2*sizeof(PetscInt)));CHKERRQ(ierr);
296 
297   apj      = (PetscInt *)(apa + cn);
298   apjdense = apj + cn;
299 
300   /* Clear old values in C */
301   ierr = PetscMemzero(ca,ci[cm]*sizeof(MatScalar));CHKERRQ(ierr);
302 
303   for (i=0;i<am;i++) {
304     /* Form sparse row of A*P */
305     anzi  = ai[i+1] - ai[i];
306     apnzj = 0;
307     for (j=0;j<anzi;j++) {
308       prow = *aj++;
309       pnzj = pi[prow+1] - pi[prow];
310       pjj  = pj + pi[prow];
311       paj  = pa + pi[prow];
312       for (k=0;k<pnzj;k++) {
313         if (!apjdense[pjj[k]]) {
314           apjdense[pjj[k]] = -1;
315           apj[apnzj++]     = pjj[k];
316         }
317         apa[pjj[k]] += (*aa)*paj[k];
318       }
319       flops += 2*pnzj;
320       aa++;
321     }
322 
323     /* Sort the j index array for quick sparse axpy. */
324     /* Note: a array does not need sorting as it is in dense storage locations. */
325     ierr = PetscSortInt(apnzj,apj);CHKERRQ(ierr);
326 
327     /* Compute P^T*A*P using outer product (P^T)[:,j]*(A*P)[j,:]. */
328     pnzi = pi[i+1] - pi[i];
329     for (j=0;j<pnzi;j++) {
330       nextap = 0;
331       crow   = *pJ++;
332       cjj    = cj + ci[crow];
333       caj    = ca + ci[crow];
334       /* Perform sparse axpy operation.  Note cjj includes apj. */
335       for (k=0;nextap<apnzj;k++) {
336         if (cjj[k]==apj[nextap]) {
337           caj[k] += (*pA)*apa[apj[nextap++]];
338         }
339       }
340       flops += 2*apnzj;
341       pA++;
342     }
343 
344     /* Zero the current row info for A*P */
345     for (j=0;j<apnzj;j++) {
346       apa[apj[j]]      = 0.;
347       apjdense[apj[j]] = 0;
348     }
349   }
350 
351   /* Assemble the final matrix and clean up */
352   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
353   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
354   ierr = PetscFree(apa);CHKERRQ(ierr);
355   ierr = PetscLogFlops(flops);CHKERRQ(ierr);
356 
357   PetscFunctionReturn(0);
358 }
359 
360 #undef __FUNCT__
361 #define __FUNCT__ "MatPtAPNumeric_SeqAIJ_SeqMAIJ"
362 PetscErrorCode MatPtAPNumeric_SeqAIJ_SeqMAIJ(Mat A,Mat PP,Mat C)
363 {
364   /* This routine requires testing -- first draft only */
365   PetscErrorCode ierr;
366   PetscInt       flops=0;
367   Mat_SeqMAIJ    *pp=(Mat_SeqMAIJ*)PP->data;
368   Mat            P=pp->AIJ;
369   Mat_SeqAIJ     *a  = (Mat_SeqAIJ *) A->data;
370   Mat_SeqAIJ     *p  = (Mat_SeqAIJ *) P->data;
371   Mat_SeqAIJ     *c  = (Mat_SeqAIJ *) C->data;
372   PetscInt       *ai=a->i,*aj=a->j,*apj,*apjdense,*pi=p->i,*pj=p->j,*pJ=p->j,*pjj;
373   PetscInt       *ci=c->i,*cj=c->j,*cjj;
374   PetscInt       am=A->M,cn=C->N,cm=C->M,ppdof=pp->dof;
375   PetscInt       i,j,k,pshift,poffset,anzi,pnzi,apnzj,nextap,pnzj,prow,crow;
376   MatScalar      *aa=a->a,*apa,*pa=p->a,*pA=p->a,*paj,*ca=c->a,*caj;
377 
378   PetscFunctionBegin;
379   /* Allocate temporary array for storage of one row of A*P */
380   ierr = PetscMalloc(cn*(sizeof(MatScalar)+2*sizeof(PetscInt)),&apa);CHKERRQ(ierr);
381   ierr = PetscMemzero(apa,cn*(sizeof(MatScalar)+2*sizeof(PetscInt)));CHKERRQ(ierr);
382 
383   apj      = (PetscInt *)(apa + cn);
384   apjdense = apj + cn;
385 
386   /* Clear old values in C */
387   ierr = PetscMemzero(ca,ci[cm]*sizeof(MatScalar));CHKERRQ(ierr);
388 
389   for (i=0;i<am;i++) {
390     /* Form sparse row of A*P */
391     anzi  = ai[i+1] - ai[i];
392     apnzj = 0;
393     for (j=0;j<anzi;j++) {
394       /* Get offset within block of P */
395       pshift = *aj%ppdof;
396       /* Get block row of P */
397       prow   = *aj++/ppdof; /* integer division */
398       pnzj = pi[prow+1] - pi[prow];
399       pjj  = pj + pi[prow];
400       paj  = pa + pi[prow];
401       for (k=0;k<pnzj;k++) {
402         poffset = pjj[k]*ppdof+pshift;
403         if (!apjdense[poffset]) {
404           apjdense[poffset] = -1;
405           apj[apnzj++]      = poffset;
406         }
407         apa[poffset] += (*aa)*paj[k];
408       }
409       flops += 2*pnzj;
410       aa++;
411     }
412 
413     /* Sort the j index array for quick sparse axpy. */
414     /* Note: a array does not need sorting as it is in dense storage locations. */
415     ierr = PetscSortInt(apnzj,apj);CHKERRQ(ierr);
416 
417     /* Compute P^T*A*P using outer product (P^T)[:,j]*(A*P)[j,:]. */
418     prow    = i/ppdof; /* integer division */
419     pshift  = i%ppdof;
420     poffset = pi[prow];
421     pnzi = pi[prow+1] - poffset;
422     /* Reset pJ and pA so we can traverse the same row of P 'dof' times. */
423     pJ   = pj+poffset;
424     pA   = pa+poffset;
425     for (j=0;j<pnzi;j++) {
426       crow   = (*pJ)*ppdof+pshift;
427       cjj    = cj + ci[crow];
428       caj    = ca + ci[crow];
429       pJ++;
430       /* Perform sparse axpy operation.  Note cjj includes apj. */
431       for (k=0,nextap=0;nextap<apnzj;k++) {
432         if (cjj[k]==apj[nextap]) {
433           caj[k] += (*pA)*apa[apj[nextap++]];
434         }
435       }
436       flops += 2*apnzj;
437       pA++;
438     }
439 
440     /* Zero the current row info for A*P */
441     for (j=0;j<apnzj;j++) {
442       apa[apj[j]]      = 0.;
443       apjdense[apj[j]] = 0;
444     }
445   }
446 
447   /* Assemble the final matrix and clean up */
448   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
449   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
450   ierr = PetscFree(apa);CHKERRQ(ierr);
451   ierr = PetscLogFlops(flops);CHKERRQ(ierr);
452 
453   PetscFunctionReturn(0);
454 }
455