xref: /petsc/src/mat/impls/aij/mpi/mpiptap.c (revision 1d63360202011afc838efb8d2268a2451fc6eefa)
1 
2 /*
3   Defines projective product routines where A is a MPIAIJ matrix
4           C = P^T * A * P
5 */
6 
7 #include <../src/mat/impls/aij/seq/aij.h>   /*I "petscmat.h" I*/
8 #include <../src/mat/utils/freespace.h>
9 #include <../src/mat/impls/aij/mpi/mpiaij.h>
10 #include <petscbt.h>
11 
12 extern PetscErrorCode MatDestroy_MPIAIJ(Mat);
13 #undef __FUNCT__
14 #define __FUNCT__ "MatDestroy_MPIAIJ_MatPtAP"
15 PetscErrorCode  MatDestroy_MPIAIJ_MatPtAP(Mat A)
16 {
17   PetscErrorCode       ierr;
18   PetscContainer       container;
19 
20   PetscFunctionBegin;
21   ierr = PetscObjectQuery((PetscObject)A,"MatMergeSeqsToMPI",(PetscObject *)&container);CHKERRQ(ierr);
22   if (container) {
23     Mat_Merge_SeqsToMPI  *merge;
24     ierr = PetscContainerGetPointer(container,(void **)&merge);CHKERRQ(ierr);
25     ierr = PetscFree(merge->id_r);CHKERRQ(ierr);
26     ierr = PetscFree(merge->len_s);CHKERRQ(ierr);
27     ierr = PetscFree(merge->len_r);CHKERRQ(ierr);
28     ierr = PetscFree(merge->bi);CHKERRQ(ierr);
29     ierr = PetscFree(merge->bj);CHKERRQ(ierr);
30     ierr = PetscFree(merge->buf_ri[0]);CHKERRQ(ierr);
31     ierr = PetscFree(merge->buf_ri);CHKERRQ(ierr);
32     ierr = PetscFree(merge->buf_rj[0]);CHKERRQ(ierr);
33     ierr = PetscFree(merge->buf_rj);CHKERRQ(ierr);
34     ierr = PetscFree(merge->coi);CHKERRQ(ierr);
35     ierr = PetscFree(merge->coj);CHKERRQ(ierr);
36     ierr = PetscFree(merge->owners_co);CHKERRQ(ierr);
37     ierr = PetscLayoutDestroy(&merge->rowmap);CHKERRQ(ierr);
38     ierr = merge->destroy(A);CHKERRQ(ierr);
39     ierr = PetscFree(merge);CHKERRQ(ierr);
40     ierr = PetscObjectCompose((PetscObject)A,"MatMergeSeqsToMPI",0);CHKERRQ(ierr);
41   }
42   PetscFunctionReturn(0);
43 }
44 
45 #undef __FUNCT__
46 #define __FUNCT__ "MatDuplicate_MPIAIJ_MatPtAP"
47 PetscErrorCode MatDuplicate_MPIAIJ_MatPtAP(Mat A, MatDuplicateOption op, Mat *M)
48 {
49   PetscErrorCode       ierr;
50   Mat_Merge_SeqsToMPI  *merge;
51   PetscContainer       container;
52 
53   PetscFunctionBegin;
54   ierr = PetscObjectQuery((PetscObject)A,"MatMergeSeqsToMPI",(PetscObject *)&container);CHKERRQ(ierr);
55   if (container) {
56     ierr  = PetscContainerGetPointer(container,(void **)&merge);CHKERRQ(ierr);
57   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Container does not exit");
58   ierr = (*merge->duplicate)(A,op,M);CHKERRQ(ierr);
59   (*M)->ops->destroy   = merge->destroy;   /* =MatDestroy_MPIAIJ, *M doesn't duplicate A's container! */
60   (*M)->ops->duplicate = merge->duplicate; /* =MatDuplicate_ MPIAIJ */
61   PetscFunctionReturn(0);
62 }
63 
64 #undef __FUNCT__
65 #define __FUNCT__ "MatPtAPSymbolic_MPIAIJ"
66 PetscErrorCode MatPtAPSymbolic_MPIAIJ(Mat A,Mat P,PetscReal fill,Mat *C)
67 {
68   PetscErrorCode ierr;
69 
70   PetscFunctionBegin;
71   if (!P->ops->ptapsymbolic_mpiaij) SETERRQ2(((PetscObject)A)->comm,PETSC_ERR_SUP,"Not implemented for A=%s and P=%s",((PetscObject)A)->type_name,((PetscObject)P)->type_name);
72   ierr = (*P->ops->ptapsymbolic_mpiaij)(A,P,fill,C);CHKERRQ(ierr);
73   PetscFunctionReturn(0);
74 }
75 
76 #undef __FUNCT__
77 #define __FUNCT__ "MatPtAPNumeric_MPIAIJ"
78 PetscErrorCode MatPtAPNumeric_MPIAIJ(Mat A,Mat P,Mat C)
79 {
80   PetscErrorCode ierr;
81 
82   PetscFunctionBegin;
83   if (!P->ops->ptapnumeric_mpiaij) SETERRQ2(((PetscObject)A)->comm,PETSC_ERR_SUP,"Not implemented for A=%s and P=%s",((PetscObject)A)->type_name,((PetscObject)P)->type_name);
84   ierr = (*P->ops->ptapnumeric_mpiaij)(A,P,C);CHKERRQ(ierr);
85   PetscFunctionReturn(0);
86 }
87 
88 #undef __FUNCT__
89 #define __FUNCT__ "MatPtAPSymbolic_MPIAIJ_MPIAIJ"
90 PetscErrorCode MatPtAPSymbolic_MPIAIJ_MPIAIJ(Mat A,Mat P,PetscReal fill,Mat *C)
91 {
92   PetscErrorCode       ierr;
93   Mat                  B_mpi;
94   Mat_MatMatMultMPI    *ap;
95   PetscContainer       container;
96   PetscFreeSpaceList   free_space=PETSC_NULL,current_space=PETSC_NULL;
97   Mat_MPIAIJ           *a=(Mat_MPIAIJ*)A->data,*p=(Mat_MPIAIJ*)P->data;
98   Mat_SeqAIJ           *ad=(Mat_SeqAIJ*)(a->A)->data,*ao=(Mat_SeqAIJ*)(a->B)->data;
99   Mat_SeqAIJ           *p_loc,*p_oth;
100   PetscInt             *pi_loc,*pj_loc,*pi_oth,*pj_oth,*pdti,*pdtj,*poti,*potj,*ptJ;
101   PetscInt             *adi=ad->i,*adj=ad->j,*aoi=ao->i,*aoj=ao->j,nnz;
102   PetscInt             nlnk,*lnk,*owners_co,*coi,*coj,i,k,pnz,row;
103   PetscInt             am=A->rmap->n,pN=P->cmap->N,pn=P->cmap->n;
104   PetscBT              lnkbt;
105   MPI_Comm             comm=((PetscObject)A)->comm;
106   PetscMPIInt          size,rank,tag,*len_si,*len_s,*len_ri;
107   PetscInt             **buf_rj,**buf_ri,**buf_ri_k;
108   PetscInt             len,proc,*dnz,*onz,*owners;
109   PetscInt             nzi,*bi,*bj;
110   PetscInt             nrows,*buf_s,*buf_si,*buf_si_i,**nextrow,**nextci;
111   MPI_Request          *swaits,*rwaits;
112   MPI_Status           *sstatus,rstatus;
113   Mat_Merge_SeqsToMPI  *merge;
114   PetscInt             *api,*apj,*Jptr,apnz,*prmap=p->garray,pon,nspacedouble=0;
115   PetscMPIInt          j;
116 
117   PetscFunctionBegin;
118   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
119   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
120 
121   /* destroy the container 'Mat_MatMatMultMPI' in case that P is attached to it */
122   ierr = PetscObjectQuery((PetscObject)P,"Mat_MatMatMultMPI",(PetscObject *)&container);CHKERRQ(ierr);
123   if (container) {
124     /* reset functions */
125     ierr = PetscContainerGetPointer(container,(void **)&ap);CHKERRQ(ierr);
126     P->ops->destroy   = ap->destroy;
127     P->ops->duplicate = ap->duplicate;
128     /* destroy container and contents */
129     ierr = PetscObjectCompose((PetscObject)P,"Mat_MatMatMultMPI",0);CHKERRQ(ierr);
130   }
131 
132   /* create the container 'Mat_MatMatMultMPI' and attach it to P */
133   ierr = PetscNew(Mat_MatMatMultMPI,&ap);CHKERRQ(ierr);
134   ap->abi=PETSC_NULL; ap->abj=PETSC_NULL;
135   ap->abnz_max = 0;
136 
137   ierr = PetscContainerCreate(PETSC_COMM_SELF,&container);CHKERRQ(ierr);
138   ierr = PetscContainerSetPointer(container,ap);CHKERRQ(ierr);
139   ierr = PetscContainerSetUserDestroy(container,PetscContainerDestroy_Mat_MatMatMultMPI);CHKERRQ(ierr);
140   ierr = PetscObjectCompose((PetscObject)P,"Mat_MatMatMultMPI",(PetscObject)container);CHKERRQ(ierr);
141   ierr = PetscContainerDestroy(&container);CHKERRQ(ierr);
142   ap->destroy     = P->ops->destroy;
143   P->ops->destroy = MatDestroy_MPIAIJ_MatMatMult;
144   ap->reuse       = MAT_INITIAL_MATRIX;
145 
146   /* get P_oth by taking rows of P (= non-zero cols of local A) from other processors */
147   ierr = MatGetBrowsOfAoCols(A,P,MAT_INITIAL_MATRIX,&ap->startsj,&ap->startsj_r,&ap->bufa,&ap->B_oth);CHKERRQ(ierr);
148   /* get P_loc by taking all local rows of P */
149   ierr = MatMPIAIJGetLocalMat(P,MAT_INITIAL_MATRIX,&ap->B_loc);CHKERRQ(ierr);
150 
151   p_loc = (Mat_SeqAIJ*)(ap->B_loc)->data;
152   p_oth = (Mat_SeqAIJ*)(ap->B_oth)->data;
153   pi_loc = p_loc->i; pj_loc = p_loc->j;
154   pi_oth = p_oth->i; pj_oth = p_oth->j;
155 
156   /* first, compute symbolic AP = A_loc*P = A_diag*P_loc + A_off*P_oth */
157   /*-------------------------------------------------------------------*/
158   ierr  = PetscMalloc((am+2)*sizeof(PetscInt),&api);CHKERRQ(ierr);
159   ap->abi = api;
160   api[0] = 0;
161 
162   /* create and initialize a linked list */
163   nlnk = pN+1;
164   ierr = PetscLLCreate(pN,pN,nlnk,lnk,lnkbt);CHKERRQ(ierr);
165 
166   /* Initial FreeSpace size is fill*nnz(A) */
167   ierr = PetscFreeSpaceGet((PetscInt)(fill*(adi[am]+aoi[am])),&free_space);CHKERRQ(ierr);
168   current_space = free_space;
169 
170   for (i=0;i<am;i++) {
171     apnz = 0;
172     /* diagonal portion of A */
173     nzi = adi[i+1] - adi[i];
174     for (j=0; j<nzi; j++){
175       row = *adj++;
176       pnz = pi_loc[row+1] - pi_loc[row];
177       Jptr  = pj_loc + pi_loc[row];
178       /* add non-zero cols of P into the sorted linked list lnk */
179       ierr = PetscLLAdd(pnz,Jptr,pN,nlnk,lnk,lnkbt);CHKERRQ(ierr);
180       apnz += nlnk;
181     }
182     /* off-diagonal portion of A */
183     nzi = aoi[i+1] - aoi[i];
184     for (j=0; j<nzi; j++){
185       row = *aoj++;
186       pnz = pi_oth[row+1] - pi_oth[row];
187       Jptr  = pj_oth + pi_oth[row];
188       ierr = PetscLLAdd(pnz,Jptr,pN,nlnk,lnk,lnkbt);CHKERRQ(ierr);
189       apnz += nlnk;
190     }
191 
192     api[i+1] = api[i] + apnz;
193     if (ap->abnz_max < apnz) ap->abnz_max = apnz;
194 
195     /* if free space is not available, double the total space in the list */
196     if (current_space->local_remaining<apnz) {
197       ierr = PetscFreeSpaceGet(apnz+current_space->total_array_size,&current_space);CHKERRQ(ierr);
198       nspacedouble++;
199     }
200 
201     /* Copy data into free space, then initialize lnk */
202     ierr = PetscLLClean(pN,pN,apnz,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
203     current_space->array           += apnz;
204     current_space->local_used      += apnz;
205     current_space->local_remaining -= apnz;
206   }
207   /* Allocate space for apj, initialize apj, and */
208   /* destroy list of free space and other temporary array(s) */
209   ierr = PetscMalloc((api[am]+1)*sizeof(PetscInt),&ap->abj);CHKERRQ(ierr);
210   apj = ap->abj;
211   ierr = PetscFreeSpaceContiguous(&free_space,ap->abj);CHKERRQ(ierr);
212 
213   /* determine symbolic Co=(p->B)^T*AP - send to others */
214   /*----------------------------------------------------*/
215   ierr = MatGetSymbolicTranspose_SeqAIJ(p->B,&poti,&potj);CHKERRQ(ierr);
216 
217   /* then, compute symbolic Co = (p->B)^T*AP */
218   pon = (p->B)->cmap->n; /* total num of rows to be sent to other processors
219                          >= (num of nonzero rows of C_seq) - pn */
220   ierr = PetscMalloc((pon+1)*sizeof(PetscInt),&coi);CHKERRQ(ierr);
221   coi[0] = 0;
222 
223   /* set initial free space to be 3*pon*max( nnz(AP) per row) */
224   nnz           = 3*pon*ap->abnz_max + 1;
225   ierr          = PetscFreeSpaceGet(nnz,&free_space);
226   current_space = free_space;
227 
228   for (i=0; i<pon; i++) {
229     nnz  = 0;
230     pnz = poti[i+1] - poti[i];
231     j     = pnz;
232     ptJ   = potj + poti[i+1];
233     while (j){/* assume cols are almost in increasing order, starting from its end saves computation */
234       j--; ptJ--;
235       row  = *ptJ; /* row of AP == col of Pot */
236       apnz = api[row+1] - api[row];
237       Jptr   = apj + api[row];
238       /* add non-zero cols of AP into the sorted linked list lnk */
239       ierr = PetscLLAdd(apnz,Jptr,pN,nlnk,lnk,lnkbt);CHKERRQ(ierr);
240       nnz += nlnk;
241     }
242 
243     /* If free space is not available, double the total space in the list */
244     if (current_space->local_remaining<nnz) {
245       ierr = PetscFreeSpaceGet(nnz+current_space->total_array_size,&current_space);CHKERRQ(ierr);
246     }
247 
248     /* Copy data into free space, and zero out denserows */
249     ierr = PetscLLClean(pN,pN,nnz,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
250     current_space->array           += nnz;
251     current_space->local_used      += nnz;
252     current_space->local_remaining -= nnz;
253     coi[i+1] = coi[i] + nnz;
254   }
255   ierr = PetscMalloc((coi[pon]+1)*sizeof(PetscInt),&coj);CHKERRQ(ierr);
256   ierr = PetscFreeSpaceContiguous(&free_space,coj);CHKERRQ(ierr);
257   ierr = MatRestoreSymbolicTranspose_SeqAIJ(p->B,&poti,&potj);CHKERRQ(ierr);
258 
259   /* send j-array (coj) of Co to other processors */
260   /*----------------------------------------------*/
261   /* determine row ownership */
262   ierr = PetscNew(Mat_Merge_SeqsToMPI,&merge);CHKERRQ(ierr);
263   ierr = PetscLayoutCreate(comm,&merge->rowmap);CHKERRQ(ierr);
264   merge->rowmap->n = pn;
265   merge->rowmap->bs = 1;
266   ierr = PetscLayoutSetUp(merge->rowmap);CHKERRQ(ierr);
267   owners = merge->rowmap->range;
268 
269   /* determine the number of messages to send, their lengths */
270   ierr = PetscMalloc(size*sizeof(PetscMPIInt),&len_si);CHKERRQ(ierr);
271   ierr = PetscMemzero(len_si,size*sizeof(PetscMPIInt));CHKERRQ(ierr);
272   ierr = PetscMalloc(size*sizeof(PetscMPIInt),&merge->len_s);CHKERRQ(ierr);
273   len_s = merge->len_s;
274   merge->nsend = 0;
275 
276   ierr = PetscMalloc((size+2)*sizeof(PetscInt),&owners_co);CHKERRQ(ierr);
277   ierr = PetscMemzero(len_s,size*sizeof(PetscMPIInt));CHKERRQ(ierr);
278 
279   proc = 0;
280   for (i=0; i<pon; i++){
281     while (prmap[i] >= owners[proc+1]) proc++;
282     len_si[proc]++;  /* num of rows in Co to be sent to [proc] */
283     len_s[proc] += coi[i+1] - coi[i];
284   }
285 
286   len   = 0;  /* max length of buf_si[] */
287   owners_co[0] = 0;
288   for (proc=0; proc<size; proc++){
289     owners_co[proc+1] = owners_co[proc] + len_si[proc];
290     if (len_si[proc]){
291       merge->nsend++;
292       len_si[proc] = 2*(len_si[proc] + 1);
293       len += len_si[proc];
294     }
295   }
296 
297   /* determine the number and length of messages to receive for coi and coj  */
298   ierr = PetscGatherNumberOfMessages(comm,PETSC_NULL,len_s,&merge->nrecv);CHKERRQ(ierr);
299   ierr = PetscGatherMessageLengths2(comm,merge->nsend,merge->nrecv,len_s,len_si,&merge->id_r,&merge->len_r,&len_ri);CHKERRQ(ierr);
300 
301   /* post the Irecv and Isend of coj */
302   ierr = PetscCommGetNewTag(comm,&tag);CHKERRQ(ierr);
303   ierr = PetscPostIrecvInt(comm,tag,merge->nrecv,merge->id_r,merge->len_r,&buf_rj,&rwaits);CHKERRQ(ierr);
304 
305   ierr = PetscMalloc((merge->nsend+1)*sizeof(MPI_Request),&swaits);CHKERRQ(ierr);
306 
307   for (proc=0, k=0; proc<size; proc++){
308     if (!len_s[proc]) continue;
309     i = owners_co[proc];
310     ierr = MPI_Isend(coj+coi[i],len_s[proc],MPIU_INT,proc,tag,comm,swaits+k);CHKERRQ(ierr);
311     k++;
312   }
313 
314   /* receives and sends of coj are complete */
315   ierr = PetscMalloc(size*sizeof(MPI_Status),&sstatus);CHKERRQ(ierr);
316   i = merge->nrecv;
317   while (i--) {
318     ierr = MPI_Waitany(merge->nrecv,rwaits,&j,&rstatus);CHKERRQ(ierr);
319   }
320   ierr = PetscFree(rwaits);CHKERRQ(ierr);
321   if (merge->nsend) {ierr = MPI_Waitall(merge->nsend,swaits,sstatus);CHKERRQ(ierr);}
322 
323   /* send and recv coi */
324   /*-------------------*/
325   ierr = PetscPostIrecvInt(comm,tag,merge->nrecv,merge->id_r,len_ri,&buf_ri,&rwaits);CHKERRQ(ierr);
326 
327   ierr = PetscMalloc((len+1)*sizeof(PetscInt),&buf_s);CHKERRQ(ierr);
328   buf_si = buf_s;  /* points to the beginning of k-th msg to be sent */
329   for (proc=0,k=0; proc<size; proc++){
330     if (!len_s[proc]) continue;
331     /* form outgoing message for i-structure:
332          buf_si[0]:                 nrows to be sent
333                [1:nrows]:           row index (global)
334                [nrows+1:2*nrows+1]: i-structure index
335     */
336     /*-------------------------------------------*/
337     nrows = len_si[proc]/2 - 1;
338     buf_si_i    = buf_si + nrows+1;
339     buf_si[0]   = nrows;
340     buf_si_i[0] = 0;
341     nrows = 0;
342     for (i=owners_co[proc]; i<owners_co[proc+1]; i++){
343       nzi = coi[i+1] - coi[i];
344       buf_si_i[nrows+1] = buf_si_i[nrows] + nzi; /* i-structure */
345       buf_si[nrows+1] =prmap[i] -owners[proc]; /* local row index */
346       nrows++;
347     }
348     ierr = MPI_Isend(buf_si,len_si[proc],MPIU_INT,proc,tag,comm,swaits+k);CHKERRQ(ierr);
349     k++;
350     buf_si += len_si[proc];
351   }
352   i = merge->nrecv;
353   while (i--) {
354     ierr = MPI_Waitany(merge->nrecv,rwaits,&j,&rstatus);CHKERRQ(ierr);
355   }
356   ierr = PetscFree(rwaits);CHKERRQ(ierr);
357   if (merge->nsend) {ierr = MPI_Waitall(merge->nsend,swaits,sstatus);CHKERRQ(ierr);}
358   /*
359   ierr = PetscInfo2(A,"nsend: %d, nrecv: %d\n",merge->nsend,merge->nrecv);CHKERRQ(ierr);
360   for (i=0; i<merge->nrecv; i++){
361     ierr = PetscInfo3(A,"recv len_ri=%d, len_rj=%d from [%d]\n",len_ri[i],merge->len_r[i],merge->id_r[i]);CHKERRQ(ierr);
362   }
363   */
364   ierr = PetscFree(len_si);CHKERRQ(ierr);
365   ierr = PetscFree(len_ri);CHKERRQ(ierr);
366   ierr = PetscFree(swaits);CHKERRQ(ierr);
367   ierr = PetscFree(sstatus);CHKERRQ(ierr);
368   ierr = PetscFree(buf_s);CHKERRQ(ierr);
369 
370   /* compute the local portion of C (mpi mat) */
371   /*------------------------------------------*/
372   ierr = MatGetSymbolicTranspose_SeqAIJ(p->A,&pdti,&pdtj);CHKERRQ(ierr);
373 
374   /* allocate bi array and free space for accumulating nonzero column info */
375   ierr = PetscMalloc((pn+1)*sizeof(PetscInt),&bi);CHKERRQ(ierr);
376   bi[0] = 0;
377 
378   /* set initial free space to be 3*pn*max( nnz(AP) per row) */
379   nnz           = 3*pn*ap->abnz_max + 1;
380   ierr          = PetscFreeSpaceGet(nnz,&free_space);
381   current_space = free_space;
382 
383   ierr = PetscMalloc3(merge->nrecv,PetscInt**,&buf_ri_k,merge->nrecv,PetscInt*,&nextrow,merge->nrecv,PetscInt*,&nextci);CHKERRQ(ierr);
384   for (k=0; k<merge->nrecv; k++){
385     buf_ri_k[k] = buf_ri[k]; /* beginning of k-th recved i-structure */
386     nrows       = *buf_ri_k[k];
387     nextrow[k]  = buf_ri_k[k] + 1;  /* next row number of k-th recved i-structure */
388     nextci[k]   = buf_ri_k[k] + (nrows + 1);/* poins to the next i-structure of k-th recved i-structure  */
389   }
390   ierr = MatPreallocateInitialize(comm,pn,pn,dnz,onz);CHKERRQ(ierr);
391   for (i=0; i<pn; i++) {
392     /* add pdt[i,:]*AP into lnk */
393     nnz = 0;
394     pnz  = pdti[i+1] - pdti[i];
395     j    = pnz;
396     ptJ  = pdtj + pdti[i+1];
397     while (j){/* assume cols are almost in increasing order, starting from its end saves computation */
398       j--; ptJ--;
399       row  = *ptJ; /* row of AP == col of Pt */
400       apnz = api[row+1] - api[row];
401       Jptr   = apj + api[row];
402       /* add non-zero cols of AP into the sorted linked list lnk */
403       ierr = PetscLLAdd(apnz,Jptr,pN,nlnk,lnk,lnkbt);CHKERRQ(ierr);
404       nnz += nlnk;
405     }
406     /* add received col data into lnk */
407     for (k=0; k<merge->nrecv; k++){ /* k-th received message */
408       if (i == *nextrow[k]) { /* i-th row */
409         nzi = *(nextci[k]+1) - *nextci[k];
410         Jptr  = buf_rj[k] + *nextci[k];
411         ierr = PetscLLAdd(nzi,Jptr,pN,nlnk,lnk,lnkbt);CHKERRQ(ierr);
412         nnz += nlnk;
413         nextrow[k]++; nextci[k]++;
414       }
415     }
416 
417     /* if free space is not available, make more free space */
418     if (current_space->local_remaining<nnz) {
419       ierr = PetscFreeSpaceGet(nnz+current_space->total_array_size,&current_space);CHKERRQ(ierr);
420     }
421     /* copy data into free space, then initialize lnk */
422     ierr = PetscLLClean(pN,pN,nnz,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
423     ierr = MatPreallocateSet(i+owners[rank],nnz,current_space->array,dnz,onz);CHKERRQ(ierr);
424     current_space->array           += nnz;
425     current_space->local_used      += nnz;
426     current_space->local_remaining -= nnz;
427     bi[i+1] = bi[i] + nnz;
428   }
429   ierr = MatRestoreSymbolicTranspose_SeqAIJ(p->A,&pdti,&pdtj);CHKERRQ(ierr);
430   ierr = PetscFree3(buf_ri_k,nextrow,nextci);CHKERRQ(ierr);
431 
432   ierr = PetscMalloc((bi[pn]+1)*sizeof(PetscInt),&bj);CHKERRQ(ierr);
433   ierr = PetscFreeSpaceContiguous(&free_space,bj);CHKERRQ(ierr);
434   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
435 
436   /* create symbolic parallel matrix B_mpi */
437   /*---------------------------------------*/
438   ierr = MatCreate(comm,&B_mpi);CHKERRQ(ierr);
439   ierr = MatSetSizes(B_mpi,pn,pn,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
440   ierr = MatSetType(B_mpi,MATMPIAIJ);CHKERRQ(ierr);
441   ierr = MatMPIAIJSetPreallocation(B_mpi,0,dnz,0,onz);CHKERRQ(ierr);
442   ierr = MatPreallocateFinalize(dnz,onz);CHKERRQ(ierr);
443 
444   merge->bi            = bi;
445   merge->bj            = bj;
446   merge->coi           = coi;
447   merge->coj           = coj;
448   merge->buf_ri        = buf_ri;
449   merge->buf_rj        = buf_rj;
450   merge->owners_co     = owners_co;
451   merge->destroy       = B_mpi->ops->destroy;
452   merge->duplicate     = B_mpi->ops->duplicate;
453 
454   /* B_mpi is not ready for use - assembly will be done by MatPtAPNumeric() */
455   B_mpi->assembled     = PETSC_FALSE;
456   B_mpi->ops->destroy  = MatDestroy_MPIAIJ_MatPtAP;
457   B_mpi->ops->duplicate = MatDuplicate_MPIAIJ_MatPtAP;
458 
459   /* attach the supporting struct to B_mpi for reuse */
460   ierr = PetscContainerCreate(PETSC_COMM_SELF,&container);CHKERRQ(ierr);
461   ierr = PetscContainerSetPointer(container,merge);CHKERRQ(ierr);
462   ierr = PetscObjectCompose((PetscObject)B_mpi,"MatMergeSeqsToMPI",(PetscObject)container);CHKERRQ(ierr);
463   ierr = PetscContainerDestroy(&container);CHKERRQ(ierr);
464   *C = B_mpi;
465 #if defined(PETSC_USE_INFO)
466   if (bi[pn] != 0) {
467     PetscReal afill = ((PetscReal)bi[pn])/(adi[am]+aoi[am]);
468     if (afill < 1.0) afill = 1.0;
469     ierr = PetscInfo3(B_mpi,"Reallocs %D; Fill ratio: given %G needed %G when computing A*P.\n",nspacedouble,fill,afill);CHKERRQ(ierr);
470     ierr = PetscInfo1(B_mpi,"Use MatPtAP(A,P,MatReuse,%G,&C) for best performance.\n",afill);CHKERRQ(ierr);
471   } else {
472     ierr = PetscInfo(B_mpi,"Empty matrix product\n");CHKERRQ(ierr);
473   }
474 #endif
475   PetscFunctionReturn(0);
476 }
477 
478 #undef __FUNCT__
479 #define __FUNCT__ "MatPtAPNumeric_MPIAIJ_MPIAIJ"
480 PetscErrorCode MatPtAPNumeric_MPIAIJ_MPIAIJ(Mat A,Mat P,Mat C)
481 {
482   PetscErrorCode       ierr;
483   Mat_Merge_SeqsToMPI  *merge;
484   Mat_MatMatMultMPI    *ap;
485   PetscContainer       cont_merge,cont_ptap;
486   Mat_MPIAIJ           *a=(Mat_MPIAIJ*)A->data,*p=(Mat_MPIAIJ*)P->data;
487   Mat_SeqAIJ           *ad=(Mat_SeqAIJ*)(a->A)->data,*ao=(Mat_SeqAIJ*)(a->B)->data;
488   Mat_SeqAIJ           *pd=(Mat_SeqAIJ*)(p->A)->data,*po=(Mat_SeqAIJ*)(p->B)->data;
489   Mat_SeqAIJ           *p_loc,*p_oth;
490   PetscInt             *adi=ad->i,*aoi=ao->i,*adj,*aoj,*apJ,nextp;
491   PetscInt             *pi_loc,*pj_loc,*pi_oth,*pj_oth,*pJ,*pj;
492   PetscInt             i,j,k,anz,pnz,apnz,nextap,row,*cj;
493   MatScalar            *ada,*aoa,*apa,*pa,*ca,*pa_loc,*pa_oth;
494   PetscInt             am=A->rmap->n,cm=C->rmap->n,pon=(p->B)->cmap->n;
495   MPI_Comm             comm=((PetscObject)C)->comm;
496   PetscMPIInt          size,rank,taga,*len_s;
497   PetscInt             *owners,proc,nrows,**buf_ri_k,**nextrow,**nextci;
498   PetscInt             **buf_ri,**buf_rj;
499   PetscInt             cnz=0,*bj_i,*bi,*bj,bnz,nextcj; /* bi,bj,ba: local array of C(mpi mat) */
500   MPI_Request          *s_waits,*r_waits;
501   MPI_Status           *status;
502   MatScalar            **abuf_r,*ba_i,*pA,*coa,*ba;
503   PetscInt             *api,*apj,*coi,*coj;
504   PetscInt             *poJ=po->j,*pdJ=pd->j,pcstart=P->cmap->rstart,pcend=P->cmap->rend;
505   PetscBool            dense_axpy=PETSC_FALSE;
506 
507   PetscFunctionBegin;
508   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
509   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
510 
511   ierr = PetscObjectQuery((PetscObject)C,"MatMergeSeqsToMPI",(PetscObject *)&cont_merge);CHKERRQ(ierr);
512   if (cont_merge) {
513     ierr  = PetscContainerGetPointer(cont_merge,(void **)&merge);CHKERRQ(ierr);
514   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Matrix C does not posses an object container");
515 
516   ierr = PetscObjectQuery((PetscObject)P,"Mat_MatMatMultMPI",(PetscObject *)&cont_ptap);CHKERRQ(ierr);
517   if (cont_ptap) {
518     ierr  = PetscContainerGetPointer(cont_ptap,(void **)&ap);CHKERRQ(ierr);
519     if (ap->reuse == MAT_INITIAL_MATRIX){
520       ap->reuse = MAT_REUSE_MATRIX;
521     } else { /* update numerical values of P_oth and P_loc */
522       ierr = MatGetBrowsOfAoCols(A,P,MAT_REUSE_MATRIX,&ap->startsj,&ap->startsj_r,&ap->bufa,&ap->B_oth);CHKERRQ(ierr);
523       ierr = MatMPIAIJGetLocalMat(P,MAT_REUSE_MATRIX,&ap->B_loc);CHKERRQ(ierr);
524     }
525   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Matrix P does not posses an object container");
526 
527   /* get data from symbolic products */
528   p_loc = (Mat_SeqAIJ*)(ap->B_loc)->data;
529   p_oth = (Mat_SeqAIJ*)(ap->B_oth)->data;
530   pi_loc=p_loc->i; pj_loc=p_loc->j; pJ=pj_loc; pa_loc=p_loc->a,pA=pa_loc;
531   pi_oth=p_oth->i; pj_oth=p_oth->j; pa_oth=p_oth->a;
532 
533   coi = merge->coi; coj = merge->coj;
534   ierr = PetscMalloc((coi[pon]+1)*sizeof(MatScalar),&coa);CHKERRQ(ierr);
535   ierr = PetscMemzero(coa,coi[pon]*sizeof(MatScalar));CHKERRQ(ierr);
536 
537   bi     = merge->bi; bj = merge->bj;
538   owners = merge->rowmap->range;
539   ierr   = PetscMalloc((bi[cm]+1)*sizeof(MatScalar),&ba);CHKERRQ(ierr);
540   ierr   = PetscMemzero(ba,bi[cm]*sizeof(MatScalar));CHKERRQ(ierr);
541 
542   /* compute numeric C_seq=P_loc^T*A_loc*P */
543   api = ap->abi; apj = ap->abj;
544   ierr = PetscOptionsGetBool(PETSC_NULL,"-matptap_denaxpy",&dense_axpy,PETSC_NULL);CHKERRQ(ierr);
545   if (dense_axpy){  /* Perform dense axpy */
546     /***********************************************************************/
547     /*
548     PetscInt prid=1;
549      if (rank==prid) printf("[%d] MatPtAPNumeric_MPIAIJ_MPIAIJ  dense_axpy...P %d %d\n",rank,P->rmap->N,P->cmap->N); */
550     /* malloc apa to store dense row A[i,:]*P */
551     ierr = PetscMalloc((P->cmap->N)*sizeof(PetscScalar),&apa);CHKERRQ(ierr);
552     ierr = PetscMemzero(apa,P->cmap->N*sizeof(PetscScalar));CHKERRQ(ierr);
553 
554     for (i=0; i<am; i++) {
555       /* form i-th sparse row of A*P */
556       apJ = apj + api[i];
557 
558       /* diagonal portion of A */
559       anz = adi[i+1] - adi[i];
560       adj = ad->j + adi[i];
561       ada = ad->a + adi[i];
562       for (j=0; j<anz; j++) {
563         row = adj[j];
564         pnz = pi_loc[row+1] - pi_loc[row];
565         pj  = pj_loc + pi_loc[row];
566         pa  = pa_loc + pi_loc[row];
567 
568         /* perform dense axpy */
569         for (k=0; k<pnz; k++){
570           apa[pj[k]] += ada[j]*pa[k];
571         }
572         ierr = PetscLogFlops(2.0*pnz);CHKERRQ(ierr);
573       }
574 
575       /* off-diagonal portion of A */
576       anz = aoi[i+1] - aoi[i];
577       aoj = ao->j + aoi[i];
578       aoa = ao->a + aoi[i];
579       for (j=0; j<anz; j++) {
580         row = aoj[j];
581         pnz = pi_oth[row+1] - pi_oth[row];
582         pj  = pj_oth + pi_oth[row];
583         pa  = pa_oth + pi_oth[row];
584 
585         /* perform dense axpy */
586         for (k=0; k<pnz; k++){
587           apa[pj[k]] += aoa[j]*pa[k];
588         }
589         ierr = PetscLogFlops(2.0*pnz);CHKERRQ(ierr);
590       }
591 
592       /* Compute P_loc[i,:]^T*AP[i,:] using outer product */
593       pnz  = pi_loc[i+1] - pi_loc[i];
594       apnz = api[i+1] - api[i];
595       for (j=0; j<pnz; j++) {
596         row    = *pJ++; /* global index */
597         if (row < pcstart || row >=pcend) { /* put the value into Co (off-diagonal part) */
598           cj  = coj + coi[*poJ];
599           ca  = coa + coi[*poJ++];
600         } else {                            /* put the value into Cd (diagonal part) */
601           cj   = bj + bi[*pdJ];
602           ca   = ba + bi[*pdJ++];
603         }
604 
605         /* perform sparse axpy */
606         nextap = 0;
607         for (k=0; nextap<apnz; k++) {
608           if (cj[k]==apJ[nextap]) { /* global column index */
609             ca[k] += (*pA)*apa[cj[k]]; nextap++;
610           }
611         }
612         ierr = PetscLogFlops(2.0*apnz);CHKERRQ(ierr);
613         pA++;
614       }
615       /* zero the current row info for A*P */
616       for (k=0; k<apnz; k++) apa[apJ[k]] = 0.0;
617     }
618     ierr = PetscFree(apa);CHKERRQ(ierr);
619     /***********************************************************************/
620   } else {/* Perform sparse axpy */
621 
622   /* malloc apa to store sparse row A[i,:]*P */
623   ierr = PetscMalloc((ap->abnz_max+1)*sizeof(MatScalar),&apa);CHKERRQ(ierr);
624   ierr = PetscMemzero(apa,ap->abnz_max*sizeof(MatScalar));CHKERRQ(ierr);
625 
626   for (i=0; i<am; i++) {
627     /* form i-th sparse row of A*P */
628     apnz = api[i+1] - api[i];
629     apJ  = apj + api[i];
630     /* diagonal portion of A */
631     anz = adi[i+1] - adi[i];
632     adj = ad->j + adi[i];
633     ada = ad->a + adi[i];
634     for (j=0; j<anz; j++) {
635       row = adj[j];
636       pnz = pi_loc[row+1] - pi_loc[row];
637       pj  = pj_loc + pi_loc[row];
638       pa  = pa_loc + pi_loc[row];
639       nextp = 0;
640       for (k=0; nextp<pnz; k++) {
641         if (apJ[k] == pj[nextp]) { /* col of AP == col of P */
642           apa[k] += ada[j]*pa[nextp++];
643         }
644       }
645       ierr = PetscLogFlops(2.0*pnz);CHKERRQ(ierr);
646     }
647     /* off-diagonal portion of A */
648     anz = aoi[i+1] - aoi[i];
649     aoj = ao->j + aoi[i];
650     aoa = ao->a + aoi[i];
651     for (j=0; j<anz; j++) {
652       row = aoj[j];
653       pnz = pi_oth[row+1] - pi_oth[row];
654       pj  = pj_oth + pi_oth[row];
655       pa  = pa_oth + pi_oth[row];
656       nextp = 0;
657       for (k=0; nextp<pnz; k++) {
658         if (apJ[k] == pj[nextp]) { /* col of AP == col of P */
659           apa[k] += aoa[j]*pa[nextp++];
660         }
661       }
662       ierr = PetscLogFlops(2.0*pnz);CHKERRQ(ierr);
663     }
664 
665     /* Compute P_loc[i,:]^T*AP[i,:] using outer product */
666     pnz = pi_loc[i+1] - pi_loc[i];
667     for (j=0; j<pnz; j++) {
668       nextap = 0;
669       row    = *pJ++; /* global index */
670       if (row < pcstart || row >=pcend) { /* put the value into Co */
671         cj  = coj + coi[*poJ];
672         ca  = coa + coi[*poJ++];
673       } else {                            /* put the value into Cd */
674         cj   = bj + bi[*pdJ];
675         ca   = ba + bi[*pdJ++];
676       }
677       for (k=0; nextap<apnz; k++) {
678         if (cj[k]==apJ[nextap]) ca[k] += (*pA)*apa[nextap++];
679       }
680       ierr = PetscLogFlops(2.0*apnz);CHKERRQ(ierr);
681       pA++;
682     }
683 
684     /* zero the current row info for A*P */
685     ierr = PetscMemzero(apa,apnz*sizeof(MatScalar));CHKERRQ(ierr);
686   }
687   ierr = PetscFree(apa);CHKERRQ(ierr);
688   }
689 
690   /* send and recv matrix values */
691   /*-----------------------------*/
692   buf_ri = merge->buf_ri;
693   buf_rj = merge->buf_rj;
694   len_s  = merge->len_s;
695   ierr = PetscCommGetNewTag(comm,&taga);CHKERRQ(ierr);
696   ierr = PetscPostIrecvScalar(comm,taga,merge->nrecv,merge->id_r,merge->len_r,&abuf_r,&r_waits);CHKERRQ(ierr);
697 
698   ierr = PetscMalloc((merge->nsend+1)*sizeof(MPI_Request),&s_waits);CHKERRQ(ierr);
699   for (proc=0,k=0; proc<size; proc++){
700     if (!len_s[proc]) continue;
701     i = merge->owners_co[proc];
702     ierr = MPI_Isend(coa+coi[i],len_s[proc],MPIU_MATSCALAR,proc,taga,comm,s_waits+k);CHKERRQ(ierr);
703     k++;
704   }
705   ierr = PetscMalloc(size*sizeof(MPI_Status),&status);CHKERRQ(ierr);
706   if (merge->nrecv) {ierr = MPI_Waitall(merge->nrecv,r_waits,status);CHKERRQ(ierr);}
707   if (merge->nsend) {ierr = MPI_Waitall(merge->nsend,s_waits,status);CHKERRQ(ierr);}
708   ierr = PetscFree(status);CHKERRQ(ierr);
709 
710   ierr = PetscFree(s_waits);CHKERRQ(ierr);
711   ierr = PetscFree(r_waits);CHKERRQ(ierr);
712   ierr = PetscFree(coa);CHKERRQ(ierr);
713 
714   /* insert local and received values into C */
715   /*-----------------------------------------*/
716   ierr = PetscMalloc3(merge->nrecv,PetscInt**,&buf_ri_k,merge->nrecv,PetscInt*,&nextrow,merge->nrecv,PetscInt*,&nextci);CHKERRQ(ierr);
717 
718   for (k=0; k<merge->nrecv; k++){
719     buf_ri_k[k] = buf_ri[k]; /* beginning of k-th recved i-structure */
720     nrows       = *(buf_ri_k[k]);
721     nextrow[k]  = buf_ri_k[k]+1;  /* next row number of k-th recved i-structure */
722     nextci[k]   = buf_ri_k[k] + (nrows + 1);/* poins to the next i-structure of k-th recved i-structure  */
723   }
724 
725   for (i=0; i<cm; i++) {
726     row = owners[rank] + i; /* global row index of C_seq */
727     bj_i = bj + bi[i];  /* col indices of the i-th row of C */
728     ba_i = ba + bi[i];
729     bnz  = bi[i+1] - bi[i];
730     /* add received vals into ba */
731     for (k=0; k<merge->nrecv; k++){ /* k-th received message */
732       /* i-th row */
733       if (i == *nextrow[k]) {
734         cnz = *(nextci[k]+1) - *nextci[k];
735         cj  = buf_rj[k] + *(nextci[k]);
736         ca  = abuf_r[k] + *(nextci[k]);
737         nextcj = 0;
738         for (j=0; nextcj<cnz; j++){
739           if (bj_i[j] == cj[nextcj]){ /* bcol == ccol */
740             ba_i[j] += ca[nextcj++];
741           }
742         }
743         nextrow[k]++; nextci[k]++;
744       }
745     }
746     ierr = MatSetValues(C,1,&row,bnz,bj_i,ba_i,INSERT_VALUES);CHKERRQ(ierr);
747     ierr = PetscLogFlops(2.0*cnz);CHKERRQ(ierr);
748   }
749   ierr = MatSetBlockSize(C,1);CHKERRQ(ierr);
750   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
751   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
752 
753   ierr = PetscFree(ba);CHKERRQ(ierr);
754   ierr = PetscFree(abuf_r[0]);CHKERRQ(ierr);
755   ierr = PetscFree(abuf_r);CHKERRQ(ierr);
756   ierr = PetscFree3(buf_ri_k,nextrow,nextci);CHKERRQ(ierr);
757   PetscFunctionReturn(0);
758 }
759