xref: /petsc/src/mat/impls/aij/mpi/mpimatmatmult.c (revision 0d04baf89eca684847eb03c0d4ee6b8dfe3c620a)
1 
2 /*
3   Defines matrix-matrix product routines for pairs of MPIAIJ matrices
4           C = A * B
5 */
6 #include <../src/mat/impls/aij/seq/aij.h> /*I "petscmat.h" I*/
7 #include <../src/mat/utils/freespace.h>
8 #include <../src/mat/impls/aij/mpi/mpiaij.h>
9 #include <petscbt.h>
10 #include <../src/mat/impls/dense/mpi/mpidense.h>
11 
12 #undef __FUNCT__
13 #define __FUNCT__ "MatMatMult_MPIAIJ_MPIAIJ"
14 PetscErrorCode MatMatMult_MPIAIJ_MPIAIJ(Mat A,Mat B,MatReuse scall,PetscReal fill, Mat *C)
15 {
16   PetscErrorCode ierr;
17 
18   PetscFunctionBegin;
19   if (scall == MAT_INITIAL_MATRIX){
20     ierr = PetscLogEventBegin(MAT_MatMultSymbolic,A,B,0,0);CHKERRQ(ierr);
21     ierr = MatMatMultSymbolic_MPIAIJ_MPIAIJ(A,B,fill,C);CHKERRQ(ierr);
22     ierr = PetscLogEventEnd(MAT_MatMultSymbolic,A,B,0,0);CHKERRQ(ierr);
23   }
24   ierr = PetscLogEventBegin(MAT_MatMultNumeric,A,B,0,0);CHKERRQ(ierr);
25   ierr = (*(*C)->ops->matmultnumeric)(A,B,*C);CHKERRQ(ierr);
26   ierr = PetscLogEventEnd(MAT_MatMultNumeric,A,B,0,0);CHKERRQ(ierr);
27   PetscFunctionReturn(0);
28 }
29 
30 #undef __FUNCT__
31 #define __FUNCT__ "PetscContainerDestroy_Mat_MatMatMultMPI"
32 PetscErrorCode PetscContainerDestroy_Mat_MatMatMultMPI(void *ptr)
33 {
34   PetscErrorCode       ierr;
35   Mat_MatMatMultMPI    *mult=(Mat_MatMatMultMPI*)ptr;
36 
37   PetscFunctionBegin;
38   ierr = ISDestroy(&mult->isrowa);CHKERRQ(ierr);
39   ierr = ISDestroy(&mult->isrowb);CHKERRQ(ierr);
40   ierr = ISDestroy(&mult->iscolb);CHKERRQ(ierr);
41   ierr = MatDestroy(&mult->C_seq);CHKERRQ(ierr);
42   ierr = MatDestroy(&mult->A_loc);CHKERRQ(ierr);
43   ierr = MatDestroy(&mult->B_seq);CHKERRQ(ierr);
44   ierr = PetscFree(mult);CHKERRQ(ierr);
45   PetscFunctionReturn(0);
46 }
47 
48 #undef __FUNCT__
49 #define __FUNCT__ "MatDestroy_MPIAIJ_MatMatMult"
50 PetscErrorCode MatDestroy_MPIAIJ_MatMatMult(Mat A)
51 {
52   PetscErrorCode ierr;
53   Mat_MPIAIJ     *a=(Mat_MPIAIJ*)A->data;
54   Mat_PtAPMPI    *ptap=a->ptap;
55 
56   PetscFunctionBegin;
57   ierr = PetscFree2(ptap->startsj,ptap->startsj_r);CHKERRQ(ierr);
58   ierr = PetscFree(ptap->bufa);CHKERRQ(ierr);
59   ierr = MatDestroy(&ptap->P_loc);CHKERRQ(ierr);
60   ierr = MatDestroy(&ptap->P_oth);CHKERRQ(ierr);
61   ierr = PetscFree(ptap->api);CHKERRQ(ierr);
62   ierr = PetscFree(ptap->apj);CHKERRQ(ierr);
63   ierr = PetscFree(ptap->apa);CHKERRQ(ierr);
64   ierr = ptap->destroy(A);CHKERRQ(ierr);
65   ierr = PetscFree(ptap);CHKERRQ(ierr);
66   PetscFunctionReturn(0);
67 }
68 
69 #undef __FUNCT__
70 #define __FUNCT__ "MatDestroy_MPIAIJ_MatMatMult_32"
71 PetscErrorCode MatDestroy_MPIAIJ_MatMatMult_32(Mat A)
72 {
73   PetscErrorCode     ierr;
74   PetscContainer     container;
75   Mat_MatMatMultMPI  *mult=PETSC_NULL;
76 
77   PetscFunctionBegin;
78   ierr = PetscObjectQuery((PetscObject)A,"Mat_MatMatMultMPI",(PetscObject *)&container);CHKERRQ(ierr);
79   if (!container) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Container does not exit");
80   ierr = PetscContainerGetPointer(container,(void **)&mult);CHKERRQ(ierr);
81   A->ops->destroy   = mult->destroy;
82   A->ops->duplicate = mult->duplicate;
83   if (A->ops->destroy) {
84     ierr = (*A->ops->destroy)(A);CHKERRQ(ierr);
85   }
86   ierr = PetscObjectCompose((PetscObject)A,"Mat_MatMatMultMPI",0);CHKERRQ(ierr);
87   PetscFunctionReturn(0);
88 }
89 
90 #undef __FUNCT__
91 #define __FUNCT__ "MatDuplicate_MPIAIJ_MatMatMult_32"
92 PetscErrorCode MatDuplicate_MPIAIJ_MatMatMult_32(Mat A, MatDuplicateOption op, Mat *M)
93 {
94   PetscErrorCode     ierr;
95   Mat_MatMatMultMPI  *mult;
96   PetscContainer     container;
97 
98   PetscFunctionBegin;
99   ierr = PetscObjectQuery((PetscObject)A,"Mat_MatMatMultMPI",(PetscObject *)&container);CHKERRQ(ierr);
100   if (!container) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Container does not exit");
101   ierr  = PetscContainerGetPointer(container,(void **)&mult);CHKERRQ(ierr);
102   /* Note: the container is not duplicated, because it requires deep copying of
103      several large data sets (see PetscContainerDestroy_Mat_MatMatMultMPI()).
104      These data sets are only used for repeated calling of MatMatMultNumeric().
105      *M is unlikely being used in this way. Thus we create *M with pure mpiaij format */
106   ierr = (*mult->duplicate)(A,op,M);CHKERRQ(ierr);
107   (*M)->ops->destroy   = mult->destroy;   /* = MatDestroy_MPIAIJ, *M doesn't duplicate A's container! */
108   (*M)->ops->duplicate = mult->duplicate; /* = MatDuplicate_MPIAIJ */
109   PetscFunctionReturn(0);
110 }
111 
112 #undef __FUNCT__
113 #define __FUNCT__ "MatDuplicate_MPIAIJ_MatMatMult"
114 PetscErrorCode MatDuplicate_MPIAIJ_MatMatMult(Mat A, MatDuplicateOption op, Mat *M)
115 {
116   PetscErrorCode     ierr;
117   Mat_MPIAIJ         *a=(Mat_MPIAIJ*)A->data;
118   Mat_PtAPMPI        *ptap=a->ptap;
119 
120   PetscFunctionBegin;
121   ierr = (*ptap->duplicate)(A,op,M);CHKERRQ(ierr);
122   (*M)->ops->destroy   = ptap->destroy;   /* = MatDestroy_MPIAIJ, *M doesn't duplicate A's special structure! */
123   (*M)->ops->duplicate = ptap->duplicate; /* = MatDuplicate_MPIAIJ */
124   PetscFunctionReturn(0);
125 }
126 
127 #undef __FUNCT__
128 #define __FUNCT__ "MatMatMultNumeric_MPIAIJ_MPIAIJ"
129 PetscErrorCode MatMatMultNumeric_MPIAIJ_MPIAIJ(Mat A,Mat P,Mat C)
130 {
131   PetscErrorCode     ierr;
132   Mat_MPIAIJ         *a=(Mat_MPIAIJ*)A->data,*c=(Mat_MPIAIJ*)C->data;
133   Mat_SeqAIJ         *ad=(Mat_SeqAIJ*)(a->A)->data,*ao=(Mat_SeqAIJ*)(a->B)->data;
134   Mat_SeqAIJ         *cd=(Mat_SeqAIJ*)(c->A)->data,*co=(Mat_SeqAIJ*)(c->B)->data;
135   PetscInt           *adi=ad->i,*adj,*aoi=ao->i,*aoj;
136   PetscScalar        *ada,*aoa,*cda=cd->a,*coa=co->a;
137   Mat_SeqAIJ         *p_loc,*p_oth;
138   PetscInt           *pi_loc,*pj_loc,*pi_oth,*pj_oth,*pj;
139   PetscScalar        *pa_loc,*pa_oth,*pa,*apa,valtmp,*ca;
140   PetscInt           cm=C->rmap->n,anz,pnz;
141   Mat_PtAPMPI        *ptap=c->ptap;
142   PetscInt           *api,*apj,*apJ,i,j,k,row;
143   PetscInt           rstart=C->rmap->rstart,cstart=C->cmap->rstart;
144   PetscInt           cdnz,conz,k0,k1;
145 
146   PetscFunctionBegin;
147   /* 1) get P_oth = ptap->P_oth  and P_loc = ptap->P_loc */
148   /*-----------------------------------------------------*/
149   /* update numerical values of P_oth and P_loc */
150   ierr = MatGetBrowsOfAoCols_MPIAIJ(A,P,MAT_REUSE_MATRIX,&ptap->startsj,&ptap->startsj_r,&ptap->bufa,&ptap->P_oth);CHKERRQ(ierr);
151   ierr = MatMPIAIJGetLocalMat(P,MAT_REUSE_MATRIX,&ptap->P_loc);CHKERRQ(ierr);
152 
153   /* 2) compute numeric C_loc = A_loc*P = Ad*P_loc + Ao*P_oth */
154   /*----------------------------------------------------------*/
155   /* get data from symbolic products */
156   p_loc = (Mat_SeqAIJ*)(ptap->P_loc)->data;
157   p_oth = (Mat_SeqAIJ*)(ptap->P_oth)->data;
158   pi_loc=p_loc->i; pj_loc=p_loc->j; pa_loc=p_loc->a;
159   pi_oth=p_oth->i; pj_oth=p_oth->j; pa_oth=p_oth->a;
160 
161   /* get apa for storing dense row A[i,:]*P */
162   apa = ptap->apa;
163 
164   for (i=0; i<cm; i++) {
165     /* diagonal portion of A */
166     anz = adi[i+1] - adi[i];
167     adj = ad->j + adi[i];
168     ada = ad->a + adi[i];
169     for (j=0; j<anz; j++) {
170       row = adj[j];
171       pnz = pi_loc[row+1] - pi_loc[row];
172       pj  = pj_loc + pi_loc[row];
173       pa  = pa_loc + pi_loc[row];
174 
175       /* perform dense axpy */
176       valtmp = ada[j];
177       for (k=0; k<pnz; k++){
178         apa[pj[k]] += valtmp*pa[k];
179       }
180       ierr = PetscLogFlops(2.0*pnz);CHKERRQ(ierr);
181     }
182 
183     /* off-diagonal portion of A */
184     anz = aoi[i+1] - aoi[i];
185     aoj = ao->j + aoi[i];
186     aoa = ao->a + aoi[i];
187     for (j=0; j<anz; j++) {
188       row = aoj[j];
189       pnz = pi_oth[row+1] - pi_oth[row];
190       pj  = pj_oth + pi_oth[row];
191       pa  = pa_oth + pi_oth[row];
192 
193       /* perform dense axpy */
194       valtmp = aoa[j];
195       for (k=0; k<pnz; k++){
196         apa[pj[k]] += valtmp*pa[k];
197       }
198       ierr = PetscLogFlops(2.0*pnz);CHKERRQ(ierr);
199     }
200 
201     /* set values in C */
202     row = rstart + i;
203     api = ptap->api;
204     apj = ptap->apj;
205     apJ = apj + api[i];
206     cdnz = cd->i[i+1] - cd->i[i];
207     conz = co->i[i+1] - co->i[i];
208 
209     /* 1st off-diagoanl part of C */
210     ca = coa + co->i[i];
211     k  = 0;
212     for (k0=0; k0<conz; k0++){
213       if (apJ[k] >= cstart) break;
214       ca[k0]      = apa[apJ[k]];
215       apa[apJ[k]] = 0.0;
216       k++;
217     }
218 
219     /* diagonal part of C */
220     ca = cda + cd->i[i];
221     for (k1=0; k1<cdnz; k1++){
222       ca[k1]      = apa[apJ[k]];
223       apa[apJ[k]] = 0.0;
224       k++;
225     }
226 
227     /* 2nd off-diagoanl part of C */
228     ca = coa + co->i[i];
229     for (; k0<conz; k0++){
230       ca[k0]      = apa[apJ[k]];
231       apa[apJ[k]] = 0.0;
232       k++;
233     }
234   }
235   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
236   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
237   PetscFunctionReturn(0);
238 }
239 
240 #undef __FUNCT__
241 #define __FUNCT__ "MatMatMultSymbolic_MPIAIJ_MPIAIJ"
242 PetscErrorCode MatMatMultSymbolic_MPIAIJ_MPIAIJ(Mat A,Mat P,PetscReal fill,Mat *C)
243 {
244   PetscErrorCode       ierr;
245   MPI_Comm             comm=((PetscObject)A)->comm;
246   Mat                  Cmpi;
247   Mat_PtAPMPI          *ptap;
248   PetscFreeSpaceList   free_space=PETSC_NULL,current_space=PETSC_NULL;
249   Mat_MPIAIJ           *a=(Mat_MPIAIJ*)A->data,*c;
250   Mat_SeqAIJ           *ad=(Mat_SeqAIJ*)(a->A)->data,*ao=(Mat_SeqAIJ*)(a->B)->data,*p_loc,*p_oth;
251   PetscInt             *pi_loc,*pj_loc,*pi_oth,*pj_oth,*dnz,*onz;
252   PetscInt             *adi=ad->i,*adj=ad->j,*aoi=ao->i,*aoj=ao->j,rstart=A->rmap->rstart;
253   PetscInt             nlnk,*lnk,i,pnz,row,*api,*apj,*Jptr,apnz,nspacedouble=0,j,nzi;
254   PetscInt             am=A->rmap->n,pN=P->cmap->N,pn=P->cmap->n,pm=P->rmap->n;
255   PetscBT              lnkbt;
256   PetscScalar          *apa;
257   PetscReal            afill;
258   PetscBool            matmatmult_old=PETSC_FALSE;
259 
260   PetscFunctionBegin;
261   if (A->cmap->rstart != P->rmap->rstart || A->cmap->rend != P->rmap->rend){
262     SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Matrix local dimensions are incompatible, (%D, %D) != (%D,%D)",A->cmap->rstart,A->cmap->rend,P->rmap->rstart,P->rmap->rend);
263   }
264   ierr = PetscOptionsGetBool(PETSC_NULL,"-matmatmult_old",&matmatmult_old,PETSC_NULL);CHKERRQ(ierr);
265   if (matmatmult_old){
266     ierr = MatMatMultSymbolic_MPIAIJ_MPIAIJ_32(A,P,fill,C);;CHKERRQ(ierr);
267     PetscFunctionReturn(0);
268   }
269 
270   /* create struct Mat_PtAPMPI and attached it to C later */
271   ierr = PetscNew(Mat_PtAPMPI,&ptap);CHKERRQ(ierr);
272 
273   /* malloc apa to store dense row A[i,:]*P */
274   ierr = PetscMalloc(pN*sizeof(PetscScalar),&apa);CHKERRQ(ierr);
275   ierr = PetscMemzero(apa,pN*sizeof(PetscScalar));CHKERRQ(ierr);
276   ptap->apa = apa;
277 
278   /* get P_oth by taking rows of P (= non-zero cols of local A) from other processors */
279   ierr = MatGetBrowsOfAoCols_MPIAIJ(A,P,MAT_INITIAL_MATRIX,&ptap->startsj,&ptap->startsj_r,&ptap->bufa,&ptap->P_oth);CHKERRQ(ierr);
280   /* get P_loc by taking all local rows of P */
281   ierr = MatMPIAIJGetLocalMat(P,MAT_INITIAL_MATRIX,&ptap->P_loc);CHKERRQ(ierr);
282 
283   p_loc = (Mat_SeqAIJ*)(ptap->P_loc)->data;
284   p_oth = (Mat_SeqAIJ*)(ptap->P_oth)->data;
285   pi_loc = p_loc->i; pj_loc = p_loc->j;
286   pi_oth = p_oth->i; pj_oth = p_oth->j;
287 
288   /* first, compute symbolic AP = A_loc*P = A_diag*P_loc + A_off*P_oth */
289   /*-------------------------------------------------------------------*/
290   ierr  = PetscMalloc((am+2)*sizeof(PetscInt),&api);CHKERRQ(ierr);
291   ptap->api = api;
292   api[0]    = 0;
293 
294   /* create and initialize a linked list */
295   nlnk = pN+1;
296   ierr = PetscLLCreate(pN,pN,nlnk,lnk,lnkbt);CHKERRQ(ierr);
297 
298   /* Initial FreeSpace size is fill*(nnz(A)+nnz(P)) */
299   ierr = PetscFreeSpaceGet((PetscInt)(fill*(adi[am]+aoi[am]+pi_loc[pm])),&free_space);CHKERRQ(ierr);
300   current_space = free_space;
301 
302   ierr = MatPreallocateInitialize(comm,am,pn,dnz,onz);CHKERRQ(ierr);
303   for (i=0; i<am; i++) {
304     apnz = 0;
305     /* diagonal portion of A */
306     nzi = adi[i+1] - adi[i];
307     for (j=0; j<nzi; j++){
308       row = *adj++;
309       pnz = pi_loc[row+1] - pi_loc[row];
310       Jptr  = pj_loc + pi_loc[row];
311       /* add non-zero cols of P into the sorted linked list lnk */
312       ierr = PetscLLAdd(pnz,Jptr,pN,nlnk,lnk,lnkbt);CHKERRQ(ierr);
313       apnz += nlnk;
314     }
315     /* off-diagonal portion of A */
316     nzi = aoi[i+1] - aoi[i];
317     for (j=0; j<nzi; j++){
318       row = *aoj++;
319       pnz = pi_oth[row+1] - pi_oth[row];
320       Jptr  = pj_oth + pi_oth[row];
321       ierr = PetscLLAdd(pnz,Jptr,pN,nlnk,lnk,lnkbt);CHKERRQ(ierr);
322       apnz += nlnk;
323     }
324 
325     api[i+1] = api[i] + apnz;
326 
327     /* if free space is not available, double the total space in the list */
328     if (current_space->local_remaining<apnz) {
329       ierr = PetscFreeSpaceGet(apnz+current_space->total_array_size,&current_space);CHKERRQ(ierr);
330       nspacedouble++;
331     }
332 
333     /* Copy data into free space, then initialize lnk */
334     ierr = PetscLLClean(pN,pN,apnz,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
335     ierr = MatPreallocateSet(i+rstart,apnz,current_space->array,dnz,onz);CHKERRQ(ierr);
336     current_space->array           += apnz;
337     current_space->local_used      += apnz;
338     current_space->local_remaining -= apnz;
339   }
340 
341   /* Allocate space for apj, initialize apj, and */
342   /* destroy list of free space and other temporary array(s) */
343   ierr = PetscMalloc((api[am]+1)*sizeof(PetscInt),&ptap->apj);CHKERRQ(ierr);
344   apj  = ptap->apj;
345   ierr = PetscFreeSpaceContiguous(&free_space,ptap->apj);CHKERRQ(ierr);
346   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
347 
348   /* create and assemble symbolic parallel matrix Cmpi */
349   /*----------------------------------------------------*/
350   ierr = MatCreate(comm,&Cmpi);CHKERRQ(ierr);
351   ierr = MatSetSizes(Cmpi,am,pn,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
352   ierr = MatSetType(Cmpi,MATMPIAIJ);CHKERRQ(ierr);
353   ierr = MatMPIAIJSetPreallocation(Cmpi,0,dnz,0,onz);CHKERRQ(ierr);
354   ierr = MatPreallocateFinalize(dnz,onz);CHKERRQ(ierr);
355   ierr = MatSetBlockSize(Cmpi,1);CHKERRQ(ierr);
356   for (i=0; i<am; i++){
357     row  = i + rstart;
358     apnz = api[i+1] - api[i];
359     ierr = MatSetValues(Cmpi,1,&row,apnz,apj,apa,INSERT_VALUES);CHKERRQ(ierr);
360     apj += apnz;
361   }
362   ierr = MatAssemblyBegin(Cmpi,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
363   ierr = MatAssemblyEnd(Cmpi,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
364 
365   ptap->destroy             = Cmpi->ops->destroy;
366   ptap->duplicate           = Cmpi->ops->duplicate;
367   Cmpi->ops->matmultnumeric = MatMatMultNumeric_MPIAIJ_MPIAIJ;
368   Cmpi->ops->destroy        = MatDestroy_MPIAIJ_MatMatMult;
369   Cmpi->ops->duplicate      = MatDuplicate_MPIAIJ_MatMatMult;
370 
371   /* attach the supporting struct to Cmpi for reuse */
372   c = (Mat_MPIAIJ*)Cmpi->data;
373   c->ptap  = ptap;
374 
375   *C = Cmpi;
376 
377   /* set MatInfo */
378   afill = (PetscReal)api[am]/(adi[am]+aoi[am]+pi_loc[pm]) + 1.e-5;
379   if (afill < 1.0) afill = 1.0;
380   Cmpi->info.mallocs           = nspacedouble;
381   Cmpi->info.fill_ratio_given  = fill;
382   Cmpi->info.fill_ratio_needed = afill;
383 
384 #if defined(PETSC_USE_INFO)
385   if (api[am]) {
386     ierr = PetscInfo3(Cmpi,"Reallocs %D; Fill ratio: given %G needed %G.\n",nspacedouble,fill,afill);CHKERRQ(ierr);
387     ierr = PetscInfo1(Cmpi,"Use MatMatMult(A,B,MatReuse,%G,&C) for best performance.;\n",afill);CHKERRQ(ierr);
388   } else {
389     ierr = PetscInfo(Cmpi,"Empty matrix product\n");CHKERRQ(ierr);
390   }
391 #endif
392   PetscFunctionReturn(0);
393 }
394 
395 /* implementation used in PETSc-3.2 */
396 /* This routine is called ONLY in the case of reusing previously computed symbolic C */
397 #undef __FUNCT__
398 #define __FUNCT__ "MatMatMultNumeric_MPIAIJ_MPIAIJ_32"
399 PetscErrorCode MatMatMultNumeric_MPIAIJ_MPIAIJ_32(Mat A,Mat B,Mat C)
400 {
401   PetscErrorCode     ierr;
402   Mat                *seq;
403   Mat_MatMatMultMPI  *mult;
404   PetscContainer     container;
405 
406   PetscFunctionBegin;
407   ierr = PetscObjectQuery((PetscObject)C,"Mat_MatMatMultMPI",(PetscObject *)&container);CHKERRQ(ierr);
408   if (!container) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Container does not exit");
409   ierr  = PetscContainerGetPointer(container,(void **)&mult);CHKERRQ(ierr);
410   seq = &mult->B_seq;
411   ierr = MatGetSubMatrices(B,1,&mult->isrowb,&mult->iscolb,MAT_REUSE_MATRIX,&seq);CHKERRQ(ierr);
412   mult->B_seq = *seq;
413 
414   seq = &mult->A_loc;
415   ierr = MatGetSubMatrices(A,1,&mult->isrowa,&mult->isrowb,MAT_REUSE_MATRIX,&seq);CHKERRQ(ierr);
416   mult->A_loc = *seq;
417 
418   ierr = MatMatMultNumeric_SeqAIJ_SeqAIJ_SparseAxpy(mult->A_loc,mult->B_seq,mult->C_seq);CHKERRQ(ierr);
419 
420   ierr = PetscObjectReference((PetscObject)mult->C_seq);CHKERRQ(ierr);
421   ierr = MatMerge(((PetscObject)A)->comm,mult->C_seq,B->cmap->n,MAT_REUSE_MATRIX,&C);CHKERRQ(ierr);
422   PetscFunctionReturn(0);
423 }
424 
425 #undef __FUNCT__
426 #define __FUNCT__ "MatMatMultSymbolic_MPIAIJ_MPIAIJ_32"
427 PetscErrorCode MatMatMultSymbolic_MPIAIJ_MPIAIJ_32(Mat A,Mat B,PetscReal fill,Mat *C)
428 {
429   PetscErrorCode     ierr;
430   Mat_MatMatMultMPI  *mult;
431   PetscContainer     container;
432   Mat                AB,*seq;
433   Mat_MPIAIJ         *a=(Mat_MPIAIJ*)A->data;
434   PetscInt           *idx,i,start,ncols,nzA,nzB,*cmap,imark;
435 
436   PetscFunctionBegin;
437   if (A->cmap->rstart != B->rmap->rstart || A->cmap->rend != B->rmap->rend){
438     SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Matrix local dimensions are incompatible, (%D, %D) != (%D,%D)",A->cmap->rstart,A->cmap->rend,B->rmap->rstart,B->rmap->rend);
439   }
440 
441   ierr = PetscNew(Mat_MatMatMultMPI,&mult);CHKERRQ(ierr);
442 
443   /* get isrowb: nonzero col of A */
444   start = A->cmap->rstart;
445   cmap  = a->garray;
446   nzA   = a->A->cmap->n;
447   nzB   = a->B->cmap->n;
448   ierr  = PetscMalloc((nzA+nzB)*sizeof(PetscInt), &idx);CHKERRQ(ierr);
449   ncols = 0;
450   for (i=0; i<nzB; i++) {  /* row < local row index */
451     if (cmap[i] < start) idx[ncols++] = cmap[i];
452     else break;
453   }
454   imark = i;
455   for (i=0; i<nzA; i++) idx[ncols++] = start + i;  /* local rows */
456   for (i=imark; i<nzB; i++) idx[ncols++] = cmap[i]; /* row > local row index */
457   ierr = ISCreateGeneral(PETSC_COMM_SELF,ncols,idx,PETSC_OWN_POINTER,&mult->isrowb);CHKERRQ(ierr);
458   ierr = ISCreateStride(PETSC_COMM_SELF,B->cmap->N,0,1,&mult->iscolb);CHKERRQ(ierr);
459 
460   /*  get isrowa: all local rows of A */
461   ierr = ISCreateStride(PETSC_COMM_SELF,A->rmap->n,A->rmap->rstart,1,&mult->isrowa);CHKERRQ(ierr);
462 
463   /* Below should go to MatMatMultNumeric_MPIAIJ_MPIAIJ() - How to generate C there? */
464   /* create a seq matrix B_seq = submatrix of B by taking rows of B that equal to nonzero col of A */
465   ierr = MatGetSubMatrices(B,1,&mult->isrowb,&mult->iscolb,MAT_INITIAL_MATRIX,&seq);CHKERRQ(ierr);
466   mult->B_seq = *seq;
467   ierr = PetscFree(seq);CHKERRQ(ierr);
468 
469   /*  create a seq matrix A_seq = submatrix of A by taking all local rows of A */
470   ierr = MatGetSubMatrices(A,1,&mult->isrowa,&mult->isrowb,MAT_INITIAL_MATRIX,&seq);CHKERRQ(ierr);
471   mult->A_loc = *seq;
472   ierr = PetscFree(seq);CHKERRQ(ierr);
473 
474   /* compute C_seq = A_seq * B_seq */
475   ierr = MatMatMultSymbolic_SeqAIJ_SeqAIJ(mult->A_loc,mult->B_seq,fill,&mult->C_seq);CHKERRQ(ierr);
476   ierr = MatMatMultNumeric_SeqAIJ_SeqAIJ(mult->A_loc,mult->B_seq,mult->C_seq);CHKERRQ(ierr);
477 
478   /* create mpi matrix C by concatinating C_seq */
479   ierr = PetscObjectReference((PetscObject)mult->C_seq);CHKERRQ(ierr); /* prevent C_seq being destroyed by MatMerge() */
480   ierr = MatMergeSymbolic(((PetscObject)A)->comm,mult->C_seq,B->cmap->n,&AB);CHKERRQ(ierr);
481   ierr = MatMergeNumeric(((PetscObject)A)->comm,mult->C_seq,B->cmap->n,AB);CHKERRQ(ierr);
482 
483   /* attach the supporting struct to C for reuse of symbolic C */
484   ierr = PetscContainerCreate(PETSC_COMM_SELF,&container);CHKERRQ(ierr);
485   ierr = PetscContainerSetPointer(container,mult);CHKERRQ(ierr);
486   ierr = PetscContainerSetUserDestroy(container,PetscContainerDestroy_Mat_MatMatMultMPI);CHKERRQ(ierr);
487   ierr = PetscObjectCompose((PetscObject)AB,"Mat_MatMatMultMPI",(PetscObject)container);CHKERRQ(ierr);
488   ierr = PetscContainerDestroy(&container);CHKERRQ(ierr);
489   mult->destroy      = AB->ops->destroy;
490   mult->duplicate    = AB->ops->duplicate;
491   AB->ops->matmultnumeric = MatMatMultNumeric_MPIAIJ_MPIAIJ_32;
492   AB->ops->destroy        = MatDestroy_MPIAIJ_MatMatMult_32;
493   AB->ops->duplicate      = MatDuplicate_MPIAIJ_MatMatMult_32;
494   AB->ops->matmult        = MatMatMult_MPIAIJ_MPIAIJ;
495   *C                      = AB;
496   PetscFunctionReturn(0);
497 }
498 
499 #undef __FUNCT__
500 #define __FUNCT__ "MatMatMult_MPIAIJ_MPIDense"
501 PetscErrorCode MatMatMult_MPIAIJ_MPIDense(Mat A,Mat B,MatReuse scall,PetscReal fill,Mat *C)
502 {
503   PetscErrorCode ierr;
504 
505   PetscFunctionBegin;
506   if (scall == MAT_INITIAL_MATRIX){
507     ierr = MatMatMultSymbolic_MPIAIJ_MPIDense(A,B,fill,C);CHKERRQ(ierr);
508   }
509   ierr = MatMatMultNumeric_MPIAIJ_MPIDense(A,B,*C);CHKERRQ(ierr);
510   PetscFunctionReturn(0);
511 }
512 
513 typedef struct {
514   Mat         workB;
515   PetscScalar *rvalues,*svalues;
516   MPI_Request *rwaits,*swaits;
517 } MPIAIJ_MPIDense;
518 
519 #undef __FUNCT__
520 #define __FUNCT__ "MPIAIJ_MPIDenseDestroy"
521 PetscErrorCode MPIAIJ_MPIDenseDestroy(void *ctx)
522 {
523   MPIAIJ_MPIDense *contents = (MPIAIJ_MPIDense*) ctx;
524   PetscErrorCode  ierr;
525 
526   PetscFunctionBegin;
527   ierr = MatDestroy(&contents->workB);CHKERRQ(ierr);
528   ierr = PetscFree4(contents->rvalues,contents->svalues,contents->rwaits,contents->swaits);CHKERRQ(ierr);
529   ierr = PetscFree(contents);CHKERRQ(ierr);
530   PetscFunctionReturn(0);
531 }
532 
533 #undef __FUNCT__
534 #define __FUNCT__ "MatMatMultSymbolic_MPIAIJ_MPIDense"
535 PetscErrorCode MatMatMultSymbolic_MPIAIJ_MPIDense(Mat A,Mat B,PetscReal fill,Mat *C)
536 {
537   PetscErrorCode         ierr;
538   Mat_MPIAIJ             *aij = (Mat_MPIAIJ*) A->data;
539   PetscInt               nz = aij->B->cmap->n;
540   PetscContainer         container;
541   MPIAIJ_MPIDense        *contents;
542   VecScatter             ctx = aij->Mvctx;
543   VecScatter_MPI_General *from = (VecScatter_MPI_General*) ctx->fromdata;
544   VecScatter_MPI_General *to   = ( VecScatter_MPI_General*) ctx->todata;
545   PetscInt               m=A->rmap->n,n=B->cmap->n;
546 
547   PetscFunctionBegin;
548   ierr = MatCreate(((PetscObject)B)->comm,C);CHKERRQ(ierr);
549   ierr = MatSetSizes(*C,m,n,A->rmap->N,B->cmap->N);CHKERRQ(ierr);
550   ierr = MatSetType(*C,MATMPIDENSE);CHKERRQ(ierr);
551   ierr = MatAssemblyBegin(*C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
552   ierr = MatAssemblyEnd(*C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
553   (*C)->ops->matmult = MatMatMult_MPIAIJ_MPIDense;
554 
555   ierr = PetscNew(MPIAIJ_MPIDense,&contents);CHKERRQ(ierr);
556   /* Create work matrix used to store off processor rows of B needed for local product */
557   ierr = MatCreateSeqDense(PETSC_COMM_SELF,nz,B->cmap->N,PETSC_NULL,&contents->workB);CHKERRQ(ierr);
558   /* Create work arrays needed */
559   ierr = PetscMalloc4(B->cmap->N*from->starts[from->n],PetscScalar,&contents->rvalues,
560                       B->cmap->N*to->starts[to->n],PetscScalar,&contents->svalues,
561                       from->n,MPI_Request,&contents->rwaits,
562                       to->n,MPI_Request,&contents->swaits);CHKERRQ(ierr);
563 
564   ierr = PetscContainerCreate(((PetscObject)A)->comm,&container);CHKERRQ(ierr);
565   ierr = PetscContainerSetPointer(container,contents);CHKERRQ(ierr);
566   ierr = PetscContainerSetUserDestroy(container,MPIAIJ_MPIDenseDestroy);CHKERRQ(ierr);
567   ierr = PetscObjectCompose((PetscObject)(*C),"workB",(PetscObject)container);CHKERRQ(ierr);
568   ierr = PetscContainerDestroy(&container);CHKERRQ(ierr);
569   PetscFunctionReturn(0);
570 }
571 
572 #undef __FUNCT__
573 #define __FUNCT__ "MatMPIDenseScatter"
574 /*
575     Performs an efficient scatter on the rows of B needed by this process; this is
576     a modification of the VecScatterBegin_() routines.
577 */
578 PetscErrorCode MatMPIDenseScatter(Mat A,Mat B,Mat C,Mat *outworkB)
579 {
580   Mat_MPIAIJ             *aij = (Mat_MPIAIJ*)A->data;
581   PetscErrorCode         ierr;
582   PetscScalar            *b,*w,*svalues,*rvalues;
583   VecScatter             ctx = aij->Mvctx;
584   VecScatter_MPI_General *from = (VecScatter_MPI_General*) ctx->fromdata;
585   VecScatter_MPI_General *to   = ( VecScatter_MPI_General*) ctx->todata;
586   PetscInt               i,j,k;
587   PetscInt               *sindices,*sstarts,*rindices,*rstarts;
588   PetscMPIInt            *sprocs,*rprocs,nrecvs;
589   MPI_Request            *swaits,*rwaits;
590   MPI_Comm               comm = ((PetscObject)A)->comm;
591   PetscMPIInt            tag = ((PetscObject)ctx)->tag,ncols = B->cmap->N, nrows = aij->B->cmap->n,imdex,nrowsB = B->rmap->n;
592   MPI_Status             status;
593   MPIAIJ_MPIDense        *contents;
594   PetscContainer         container;
595   Mat                    workB;
596 
597   PetscFunctionBegin;
598   ierr = PetscObjectQuery((PetscObject)C,"workB",(PetscObject*)&container);CHKERRQ(ierr);
599   if (!container) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Container does not exit");
600   ierr = PetscContainerGetPointer(container,(void**)&contents);CHKERRQ(ierr);
601 
602   workB = *outworkB = contents->workB;
603   if (nrows != workB->rmap->n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Number of rows of workB %D not equal to columns of aij->B %D",nrows,workB->cmap->n);
604   sindices  = to->indices;
605   sstarts   = to->starts;
606   sprocs    = to->procs;
607   swaits    = contents->swaits;
608   svalues   = contents->svalues;
609 
610   rindices  = from->indices;
611   rstarts   = from->starts;
612   rprocs    = from->procs;
613   rwaits    = contents->rwaits;
614   rvalues   = contents->rvalues;
615 
616   ierr = MatGetArray(B,&b);CHKERRQ(ierr);
617   ierr = MatGetArray(workB,&w);CHKERRQ(ierr);
618 
619   for (i=0; i<from->n; i++) {
620     ierr = MPI_Irecv(rvalues+ncols*rstarts[i],ncols*(rstarts[i+1]-rstarts[i]),MPIU_SCALAR,rprocs[i],tag,comm,rwaits+i);CHKERRQ(ierr);
621   }
622 
623   for (i=0; i<to->n; i++) {
624     /* pack a message at a time */
625     CHKMEMQ;
626     for (j=0; j<sstarts[i+1]-sstarts[i]; j++){
627       for (k=0; k<ncols; k++) {
628         svalues[ncols*(sstarts[i] + j) + k] = b[sindices[sstarts[i]+j] + nrowsB*k];
629       }
630     }
631     CHKMEMQ;
632     ierr = MPI_Isend(svalues+ncols*sstarts[i],ncols*(sstarts[i+1]-sstarts[i]),MPIU_SCALAR,sprocs[i],tag,comm,swaits+i);CHKERRQ(ierr);
633   }
634 
635   nrecvs = from->n;
636   while (nrecvs) {
637     ierr = MPI_Waitany(from->n,rwaits,&imdex,&status);CHKERRQ(ierr);
638     nrecvs--;
639     /* unpack a message at a time */
640     CHKMEMQ;
641     for (j=0; j<rstarts[imdex+1]-rstarts[imdex]; j++){
642       for (k=0; k<ncols; k++) {
643         w[rindices[rstarts[imdex]+j] + nrows*k] = rvalues[ncols*(rstarts[imdex] + j) + k];
644       }
645     }
646     CHKMEMQ;
647   }
648   if (to->n) {ierr = MPI_Waitall(to->n,swaits,to->sstatus);CHKERRQ(ierr);}
649 
650   ierr = MatRestoreArray(B,&b);CHKERRQ(ierr);
651   ierr = MatRestoreArray(workB,&w);CHKERRQ(ierr);
652   ierr = MatAssemblyBegin(workB,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
653   ierr = MatAssemblyEnd(workB,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
654   PetscFunctionReturn(0);
655 }
656 extern PetscErrorCode MatMatMultNumericAdd_SeqAIJ_SeqDense(Mat,Mat,Mat);
657 
658 #undef __FUNCT__
659 #define __FUNCT__ "MatMatMultNumeric_MPIAIJ_MPIDense"
660 PetscErrorCode MatMatMultNumeric_MPIAIJ_MPIDense(Mat A,Mat B,Mat C)
661 {
662   PetscErrorCode       ierr;
663   Mat_MPIAIJ           *aij = (Mat_MPIAIJ*)A->data;
664   Mat_MPIDense         *bdense = (Mat_MPIDense*)B->data;
665   Mat_MPIDense         *cdense = (Mat_MPIDense*)C->data;
666   Mat                  workB;
667 
668   PetscFunctionBegin;
669 
670   /* diagonal block of A times all local rows of B*/
671   ierr = MatMatMultNumeric_SeqAIJ_SeqDense(aij->A,bdense->A,cdense->A);CHKERRQ(ierr);
672 
673   /* get off processor parts of B needed to complete the product */
674   ierr = MatMPIDenseScatter(A,B,C,&workB);CHKERRQ(ierr);
675 
676   /* off-diagonal block of A times nonlocal rows of B */
677   ierr = MatMatMultNumericAdd_SeqAIJ_SeqDense(aij->B,workB,cdense->A);CHKERRQ(ierr);
678   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
679   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
680   PetscFunctionReturn(0);
681 }
682 
683