xref: /petsc/src/mat/impls/baij/mpi/baijov.c (revision 5c8f6a953e7ed1c81f507d64aebddb11080b60e9)
1 
2 /*
3    Routines to compute overlapping regions of a parallel MPI matrix
4   and to find submatrices that were shared across processors.
5 */
6 #include <../src/mat/impls/baij/mpi/mpibaij.h>
7 #include <petscbt.h>
8 
9 static PetscErrorCode MatIncreaseOverlap_MPIBAIJ_Local(Mat,PetscInt,char **,PetscInt*,PetscInt**);
10 static PetscErrorCode MatIncreaseOverlap_MPIBAIJ_Receive(Mat,PetscInt,PetscInt **,PetscInt**,PetscInt*);
11 extern PetscErrorCode MatGetRow_MPIBAIJ(Mat,PetscInt,PetscInt*,PetscInt**,PetscScalar**);
12 extern PetscErrorCode MatRestoreRow_MPIBAIJ(Mat,PetscInt,PetscInt*,PetscInt**,PetscScalar**);
13 
14 #undef __FUNCT__
15 #define __FUNCT__ "MatIncreaseOverlap_MPIBAIJ"
16 PetscErrorCode MatIncreaseOverlap_MPIBAIJ(Mat C,PetscInt imax,IS is[],PetscInt ov)
17 {
18   PetscErrorCode ierr;
19   PetscInt       i,N=C->cmap->N, bs=C->rmap->bs;
20   IS             *is_new;
21 
22   PetscFunctionBegin;
23   ierr = PetscMalloc(imax*sizeof(IS),&is_new);CHKERRQ(ierr);
24   /* Convert the indices into block format */
25   ierr = ISCompressIndicesGeneral(N,C->rmap->n,bs,imax,is,is_new);CHKERRQ(ierr);
26   if (ov < 0) { SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Negative overlap specified\n");}
27   for (i=0; i<ov; ++i) {
28     ierr = MatIncreaseOverlap_MPIBAIJ_Once(C,imax,is_new);CHKERRQ(ierr);
29   }
30   for (i=0; i<imax; i++) {ierr = ISDestroy(&is[i]);CHKERRQ(ierr);}
31   ierr = ISExpandIndicesGeneral(N,N,bs,imax,is_new,is);CHKERRQ(ierr);
32   for (i=0; i<imax; i++) {ierr = ISDestroy(&is_new[i]);CHKERRQ(ierr);}
33   ierr = PetscFree(is_new);CHKERRQ(ierr);
34   PetscFunctionReturn(0);
35 }
36 
37 /*
38   Sample message format:
39   If a processor A wants processor B to process some elements corresponding
40   to index sets is[1], is[5]
41   mesg [0] = 2   (no of index sets in the mesg)
42   -----------
43   mesg [1] = 1 => is[1]
44   mesg [2] = sizeof(is[1]);
45   -----------
46   mesg [5] = 5  => is[5]
47   mesg [6] = sizeof(is[5]);
48   -----------
49   mesg [7]
50   mesg [n]  data(is[1])
51   -----------
52   mesg[n+1]
53   mesg[m]  data(is[5])
54   -----------
55 
56   Notes:
57   nrqs - no of requests sent (or to be sent out)
58   nrqr - no of requests recieved (which have to be or which have been processed
59 */
60 #undef __FUNCT__
61 #define __FUNCT__ "MatIncreaseOverlap_MPIBAIJ_Once"
62 PetscErrorCode MatIncreaseOverlap_MPIBAIJ_Once(Mat C,PetscInt imax,IS is[])
63 {
64   Mat_MPIBAIJ    *c = (Mat_MPIBAIJ*)C->data;
65   const PetscInt **idx,*idx_i;
66   PetscInt       *n,*w3,*w4,**data,len;
67   PetscErrorCode ierr;
68   PetscMPIInt    size,rank,tag1,tag2,*w2,*w1,nrqr;
69   PetscInt       Mbs,i,j,k,**rbuf,row,proc=-1,nrqs,msz,**outdat,**ptr;
70   PetscInt       *ctr,*pa,*tmp,*isz,*isz1,**xdata,**rbuf2,*d_p;
71   PetscMPIInt    *onodes1,*olengths1,*onodes2,*olengths2;
72   PetscBT        *table;
73   MPI_Comm       comm;
74   MPI_Request    *s_waits1,*r_waits1,*s_waits2,*r_waits2;
75   MPI_Status     *s_status,*recv_status;
76   char           *t_p;
77 
78   PetscFunctionBegin;
79   comm   = ((PetscObject)C)->comm;
80   size   = c->size;
81   rank   = c->rank;
82   Mbs    = c->Mbs;
83 
84   ierr = PetscObjectGetNewTag((PetscObject)C,&tag1);CHKERRQ(ierr);
85   ierr = PetscObjectGetNewTag((PetscObject)C,&tag2);CHKERRQ(ierr);
86 
87   ierr = PetscMalloc2(imax+1,const PetscInt*,&idx,imax,PetscInt,&n);CHKERRQ(ierr);
88 
89   for (i=0; i<imax; i++) {
90     ierr = ISGetIndices(is[i],&idx[i]);CHKERRQ(ierr);
91     ierr = ISGetLocalSize(is[i],&n[i]);CHKERRQ(ierr);
92   }
93 
94   /* evaluate communication - mesg to who,length of mesg, and buffer space
95      required. Based on this, buffers are allocated, and data copied into them*/
96   ierr = PetscMalloc4(size,PetscMPIInt,&w1,size,PetscMPIInt,&w2,size,PetscInt,&w3,size,PetscInt,&w4);CHKERRQ(ierr);
97   ierr = PetscMemzero(w1,size*sizeof(PetscMPIInt));CHKERRQ(ierr);
98   ierr = PetscMemzero(w2,size*sizeof(PetscMPIInt));CHKERRQ(ierr);
99   ierr = PetscMemzero(w3,size*sizeof(PetscInt));CHKERRQ(ierr);
100   for (i=0; i<imax; i++) {
101     ierr  = PetscMemzero(w4,size*sizeof(PetscInt));CHKERRQ(ierr); /* initialise work vector*/
102     idx_i = idx[i];
103     len   = n[i];
104     for (j=0; j<len; j++) {
105       row  = idx_i[j];
106       if (row < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Index set cannot have negative entries");
107       ierr = PetscLayoutFindOwner(C->rmap,row*C->rmap->bs,&proc);CHKERRQ(ierr);
108       w4[proc]++;
109     }
110     for (j=0; j<size; j++) {
111       if (w4[j]) { w1[j] += w4[j]; w3[j]++;}
112     }
113   }
114 
115   nrqs     = 0;              /* no of outgoing messages */
116   msz      = 0;              /* total mesg length (for all proc */
117   w1[rank] = 0;              /* no mesg sent to itself */
118   w3[rank] = 0;
119   for (i=0; i<size; i++) {
120     if (w1[i])  {w2[i] = 1; nrqs++;} /* there exists a message to proc i */
121   }
122   /* pa - is list of processors to communicate with */
123   ierr = PetscMalloc((nrqs+1)*sizeof(PetscInt),&pa);CHKERRQ(ierr);
124   for (i=0,j=0; i<size; i++) {
125     if (w1[i]) {pa[j] = i; j++;}
126   }
127 
128   /* Each message would have a header = 1 + 2*(no of IS) + data */
129   for (i=0; i<nrqs; i++) {
130     j      = pa[i];
131     w1[j] += w2[j] + 2*w3[j];
132     msz   += w1[j];
133   }
134 
135   /* Determine the number of messages to expect, their lengths, from from-ids */
136   ierr = PetscGatherNumberOfMessages(comm,w2,w1,&nrqr);CHKERRQ(ierr);
137   ierr = PetscGatherMessageLengths(comm,nrqs,nrqr,w1,&onodes1,&olengths1);CHKERRQ(ierr);
138 
139   /* Now post the Irecvs corresponding to these messages */
140   ierr = PetscPostIrecvInt(comm,tag1,nrqr,onodes1,olengths1,&rbuf,&r_waits1);CHKERRQ(ierr);
141 
142   /* Allocate Memory for outgoing messages */
143   ierr = PetscMalloc4(size,PetscInt*,&outdat,size,PetscInt*,&ptr,msz,PetscInt,&tmp,size,PetscInt,&ctr);CHKERRQ(ierr);
144   ierr = PetscMemzero(outdat,size*sizeof(PetscInt*));CHKERRQ(ierr);
145   ierr = PetscMemzero(ptr,size*sizeof(PetscInt*));CHKERRQ(ierr);
146   {
147     PetscInt *iptr = tmp,ict  = 0;
148     for (i=0; i<nrqs; i++) {
149       j         = pa[i];
150       iptr     +=  ict;
151       outdat[j] = iptr;
152       ict       = w1[j];
153     }
154   }
155 
156   /* Form the outgoing messages */
157   /*plug in the headers*/
158   for (i=0; i<nrqs; i++) {
159     j            = pa[i];
160     outdat[j][0] = 0;
161     ierr = PetscMemzero(outdat[j]+1,2*w3[j]*sizeof(PetscInt));CHKERRQ(ierr);
162     ptr[j]       = outdat[j] + 2*w3[j] + 1;
163   }
164 
165   /* Memory for doing local proc's work*/
166   {
167     ierr = PetscMalloc5(imax,PetscBT,&table, imax,PetscInt*,&data, imax,PetscInt,&isz,
168                         Mbs*imax,PetscInt,&d_p, (Mbs/PETSC_BITS_PER_BYTE+1)*imax,char,&t_p);CHKERRQ(ierr);
169     ierr = PetscMemzero(table,imax*sizeof(PetscBT));CHKERRQ(ierr);
170     ierr = PetscMemzero(data,imax*sizeof(PetscInt*));CHKERRQ(ierr);
171     ierr = PetscMemzero(isz,imax*sizeof(PetscInt));CHKERRQ(ierr);
172     ierr = PetscMemzero(d_p,Mbs*imax*sizeof(PetscInt));CHKERRQ(ierr);
173     ierr = PetscMemzero(t_p,(Mbs/PETSC_BITS_PER_BYTE+1)*imax*sizeof(char));CHKERRQ(ierr);
174 
175     for (i=0; i<imax; i++) {
176       table[i] = t_p + (Mbs/PETSC_BITS_PER_BYTE+1)*i;
177       data[i]  = d_p + (Mbs)*i;
178     }
179   }
180 
181   /* Parse the IS and update local tables and the outgoing buf with the data*/
182   {
183     PetscInt n_i,*data_i,isz_i,*outdat_j,ctr_j;
184     PetscBT  table_i;
185 
186     for (i=0; i<imax; i++) {
187       ierr    = PetscMemzero(ctr,size*sizeof(PetscInt));CHKERRQ(ierr);
188       n_i     = n[i];
189       table_i = table[i];
190       idx_i   = idx[i];
191       data_i  = data[i];
192       isz_i   = isz[i];
193       for (j=0;  j<n_i; j++) {  /* parse the indices of each IS */
194         row  = idx_i[j];
195         ierr = PetscLayoutFindOwner(C->rmap,row*C->rmap->bs,&proc);CHKERRQ(ierr);
196         if (proc != rank) { /* copy to the outgoing buffer */
197           ctr[proc]++;
198           *ptr[proc] = row;
199           ptr[proc]++;
200         } else { /* Update the local table */
201           if (!PetscBTLookupSet(table_i,row)) { data_i[isz_i++] = row;}
202         }
203       }
204       /* Update the headers for the current IS */
205       for (j=0; j<size; j++) { /* Can Optimise this loop by using pa[] */
206         if ((ctr_j = ctr[j])) {
207           outdat_j        = outdat[j];
208           k               = ++outdat_j[0];
209           outdat_j[2*k]   = ctr_j;
210           outdat_j[2*k-1] = i;
211         }
212       }
213       isz[i] = isz_i;
214     }
215   }
216 
217   /*  Now  post the sends */
218   ierr = PetscMalloc((nrqs+1)*sizeof(MPI_Request),&s_waits1);CHKERRQ(ierr);
219   for (i=0; i<nrqs; ++i) {
220     j    = pa[i];
221     ierr = MPI_Isend(outdat[j],w1[j],MPIU_INT,j,tag1,comm,s_waits1+i);CHKERRQ(ierr);
222   }
223 
224   /* No longer need the original indices*/
225   for (i=0; i<imax; ++i) {
226     ierr = ISRestoreIndices(is[i],idx+i);CHKERRQ(ierr);
227   }
228   ierr = PetscFree2(idx,n);CHKERRQ(ierr);
229 
230   for (i=0; i<imax; ++i) {
231     ierr = ISDestroy(&is[i]);CHKERRQ(ierr);
232   }
233 
234   /* Do Local work*/
235   ierr = MatIncreaseOverlap_MPIBAIJ_Local(C,imax,table,isz,data);CHKERRQ(ierr);
236 
237   /* Receive messages*/
238   ierr = PetscMalloc((nrqr+1)*sizeof(MPI_Status),&recv_status);CHKERRQ(ierr);
239   if (nrqr) {ierr = MPI_Waitall(nrqr,r_waits1,recv_status);CHKERRQ(ierr);}
240 
241   ierr = PetscMalloc((nrqs+1)*sizeof(MPI_Status),&s_status);CHKERRQ(ierr);
242   if (nrqs) {ierr = MPI_Waitall(nrqs,s_waits1,s_status);CHKERRQ(ierr);}
243 
244   /* Phase 1 sends are complete - deallocate buffers */
245   ierr = PetscFree4(outdat,ptr,tmp,ctr);CHKERRQ(ierr);
246   ierr = PetscFree4(w1,w2,w3,w4);CHKERRQ(ierr);
247 
248   ierr = PetscMalloc((nrqr+1)*sizeof(PetscInt*),&xdata);CHKERRQ(ierr);
249   ierr = PetscMalloc((nrqr+1)*sizeof(PetscInt),&isz1);CHKERRQ(ierr);
250   ierr = MatIncreaseOverlap_MPIBAIJ_Receive(C,nrqr,rbuf,xdata,isz1);CHKERRQ(ierr);
251   ierr = PetscFree(rbuf[0]);CHKERRQ(ierr);
252   ierr = PetscFree(rbuf);CHKERRQ(ierr);
253 
254   /* Send the data back*/
255   /* Do a global reduction to know the buffer space req for incoming messages*/
256   {
257     PetscMPIInt *rw1;
258 
259     ierr = PetscMalloc(size*sizeof(PetscInt),&rw1);CHKERRQ(ierr);
260     ierr = PetscMemzero(rw1,size*sizeof(PetscInt));CHKERRQ(ierr);
261 
262     for (i=0; i<nrqr; ++i) {
263       proc      = recv_status[i].MPI_SOURCE;
264       if (proc != onodes1[i]) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"MPI_SOURCE mismatch");
265       rw1[proc] = isz1[i];
266     }
267 
268     ierr = PetscFree(onodes1);CHKERRQ(ierr);
269     ierr = PetscFree(olengths1);CHKERRQ(ierr);
270 
271     /* Determine the number of messages to expect, their lengths, from from-ids */
272     ierr = PetscGatherMessageLengths(comm,nrqr,nrqs,rw1,&onodes2,&olengths2);CHKERRQ(ierr);
273     ierr = PetscFree(rw1);CHKERRQ(ierr);
274   }
275   /* Now post the Irecvs corresponding to these messages */
276   ierr = PetscPostIrecvInt(comm,tag2,nrqs,onodes2,olengths2,&rbuf2,&r_waits2);CHKERRQ(ierr);
277 
278   /*  Now  post the sends */
279   ierr = PetscMalloc((nrqr+1)*sizeof(MPI_Request),&s_waits2);CHKERRQ(ierr);
280   for (i=0; i<nrqr; ++i) {
281     j    = recv_status[i].MPI_SOURCE;
282     ierr = MPI_Isend(xdata[i],isz1[i],MPIU_INT,j,tag2,comm,s_waits2+i);CHKERRQ(ierr);
283   }
284 
285   /* receive work done on other processors*/
286   {
287     PetscMPIInt idex;
288     PetscInt    is_no,ct1,max,*rbuf2_i,isz_i,*data_i,jmax;
289     PetscBT     table_i;
290     MPI_Status  *status2;
291 
292     ierr = PetscMalloc((PetscMax(nrqr,nrqs)+1)*sizeof(MPI_Status),&status2);CHKERRQ(ierr);
293     for (i=0; i<nrqs; ++i) {
294       ierr = MPI_Waitany(nrqs,r_waits2,&idex,status2+i);CHKERRQ(ierr);
295       /* Process the message*/
296       rbuf2_i = rbuf2[idex];
297       ct1     = 2*rbuf2_i[0]+1;
298       jmax    = rbuf2[idex][0];
299       for (j=1; j<=jmax; j++) {
300         max     = rbuf2_i[2*j];
301         is_no   = rbuf2_i[2*j-1];
302         isz_i   = isz[is_no];
303         data_i  = data[is_no];
304         table_i = table[is_no];
305         for (k=0; k<max; k++,ct1++) {
306           row = rbuf2_i[ct1];
307           if (!PetscBTLookupSet(table_i,row)) { data_i[isz_i++] = row;}
308         }
309         isz[is_no] = isz_i;
310       }
311     }
312     if (nrqr) {ierr = MPI_Waitall(nrqr,s_waits2,status2);CHKERRQ(ierr);}
313     ierr = PetscFree(status2);CHKERRQ(ierr);
314   }
315 
316   for (i=0; i<imax; ++i) {
317     ierr = ISCreateGeneral(PETSC_COMM_SELF,isz[i],data[i],PETSC_COPY_VALUES,is+i);CHKERRQ(ierr);
318   }
319 
320 
321   ierr = PetscFree(onodes2);CHKERRQ(ierr);
322   ierr = PetscFree(olengths2);CHKERRQ(ierr);
323 
324   ierr = PetscFree(pa);CHKERRQ(ierr);
325   ierr = PetscFree(rbuf2[0]);CHKERRQ(ierr);
326   ierr = PetscFree(rbuf2);CHKERRQ(ierr);
327   ierr = PetscFree(s_waits1);CHKERRQ(ierr);
328   ierr = PetscFree(r_waits1);CHKERRQ(ierr);
329   ierr = PetscFree(s_waits2);CHKERRQ(ierr);
330   ierr = PetscFree(r_waits2);CHKERRQ(ierr);
331   ierr = PetscFree5(table,data,isz,d_p,t_p);CHKERRQ(ierr);
332   ierr = PetscFree(s_status);CHKERRQ(ierr);
333   ierr = PetscFree(recv_status);CHKERRQ(ierr);
334   ierr = PetscFree(xdata[0]);CHKERRQ(ierr);
335   ierr = PetscFree(xdata);CHKERRQ(ierr);
336   ierr = PetscFree(isz1);CHKERRQ(ierr);
337   PetscFunctionReturn(0);
338 }
339 
340 #undef __FUNCT__
341 #define __FUNCT__ "MatIncreaseOverlap_MPIBAIJ_Local"
342 /*
343    MatIncreaseOverlap_MPIBAIJ_Local - Called by MatincreaseOverlap, to do
344        the work on the local processor.
345 
346      Inputs:
347       C      - MAT_MPIBAIJ;
348       imax - total no of index sets processed at a time;
349       table  - an array of char - size = Mbs bits.
350 
351      Output:
352       isz    - array containing the count of the solution elements corresponding
353                to each index set;
354       data   - pointer to the solutions
355 */
356 static PetscErrorCode MatIncreaseOverlap_MPIBAIJ_Local(Mat C,PetscInt imax,PetscBT *table,PetscInt *isz,PetscInt **data)
357 {
358   Mat_MPIBAIJ *c = (Mat_MPIBAIJ*)C->data;
359   Mat         A = c->A,B = c->B;
360   Mat_SeqBAIJ *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ*)B->data;
361   PetscInt    start,end,val,max,rstart,cstart,*ai,*aj;
362   PetscInt    *bi,*bj,*garray,i,j,k,row,*data_i,isz_i;
363   PetscBT     table_i;
364 
365   PetscFunctionBegin;
366   rstart = c->rstartbs;
367   cstart = c->cstartbs;
368   ai     = a->i;
369   aj     = a->j;
370   bi     = b->i;
371   bj     = b->j;
372   garray = c->garray;
373 
374 
375   for (i=0; i<imax; i++) {
376     data_i  = data[i];
377     table_i = table[i];
378     isz_i   = isz[i];
379     for (j=0,max=isz[i]; j<max; j++) {
380       row   = data_i[j] - rstart;
381       start = ai[row];
382       end   = ai[row+1];
383       for (k=start; k<end; k++) { /* Amat */
384         val = aj[k] + cstart;
385         if (!PetscBTLookupSet(table_i,val)) { data_i[isz_i++] = val;}
386       }
387       start = bi[row];
388       end   = bi[row+1];
389       for (k=start; k<end; k++) { /* Bmat */
390         val = garray[bj[k]];
391         if (!PetscBTLookupSet(table_i,val)) { data_i[isz_i++] = val;}
392       }
393     }
394     isz[i] = isz_i;
395   }
396   PetscFunctionReturn(0);
397 }
398 #undef __FUNCT__
399 #define __FUNCT__ "MatIncreaseOverlap_MPIBAIJ_Receive"
400 /*
401       MatIncreaseOverlap_MPIBAIJ_Receive - Process the recieved messages,
402          and return the output
403 
404          Input:
405            C    - the matrix
406            nrqr - no of messages being processed.
407            rbuf - an array of pointers to the recieved requests
408 
409          Output:
410            xdata - array of messages to be sent back
411            isz1  - size of each message
412 
413   For better efficiency perhaps we should malloc separately each xdata[i],
414 then if a remalloc is required we need only copy the data for that one row
415 rather than all previous rows as it is now where a single large chunck of
416 memory is used.
417 
418 */
419 static PetscErrorCode MatIncreaseOverlap_MPIBAIJ_Receive(Mat C,PetscInt nrqr,PetscInt **rbuf,PetscInt **xdata,PetscInt * isz1)
420 {
421   Mat_MPIBAIJ    *c = (Mat_MPIBAIJ*)C->data;
422   Mat            A = c->A,B = c->B;
423   Mat_SeqBAIJ    *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ*)B->data;
424   PetscErrorCode ierr;
425   PetscInt       rstart,cstart,*ai,*aj,*bi,*bj,*garray,i,j,k;
426   PetscInt       row,total_sz,ct,ct1,ct2,ct3,mem_estimate,oct2,l,start,end;
427   PetscInt       val,max1,max2,Mbs,no_malloc =0,*tmp,new_estimate,ctr;
428   PetscInt       *rbuf_i,kmax,rbuf_0;
429   PetscBT        xtable;
430 
431   PetscFunctionBegin;
432   Mbs    = c->Mbs;
433   rstart = c->rstartbs;
434   cstart = c->cstartbs;
435   ai     = a->i;
436   aj     = a->j;
437   bi     = b->i;
438   bj     = b->j;
439   garray = c->garray;
440 
441 
442   for (i=0,ct=0,total_sz=0; i<nrqr; ++i) {
443     rbuf_i  =  rbuf[i];
444     rbuf_0  =  rbuf_i[0];
445     ct     += rbuf_0;
446     for (j=1; j<=rbuf_0; j++) { total_sz += rbuf_i[2*j]; }
447   }
448 
449   if (c->Mbs) max1 = ct*(a->nz +b->nz)/c->Mbs;
450   else        max1 = 1;
451   mem_estimate = 3*((total_sz > max1 ? total_sz : max1)+1);
452   ierr         = PetscMalloc(mem_estimate*sizeof(PetscInt),&xdata[0]);CHKERRQ(ierr);
453   ++no_malloc;
454   ierr         = PetscBTCreate(Mbs,&xtable);CHKERRQ(ierr);
455   ierr         = PetscMemzero(isz1,nrqr*sizeof(PetscInt));CHKERRQ(ierr);
456 
457   ct3 = 0;
458   for (i=0; i<nrqr; i++) { /* for easch mesg from proc i */
459     rbuf_i =  rbuf[i];
460     rbuf_0 =  rbuf_i[0];
461     ct1    =  2*rbuf_0+1;
462     ct2    =  ct1;
463     ct3    += ct1;
464     for (j=1; j<=rbuf_0; j++) { /* for each IS from proc i*/
465       ierr = PetscBTMemzero(Mbs,xtable);CHKERRQ(ierr);
466       oct2 = ct2;
467       kmax = rbuf_i[2*j];
468       for (k=0; k<kmax; k++,ct1++) {
469         row = rbuf_i[ct1];
470         if (!PetscBTLookupSet(xtable,row)) {
471           if (!(ct3 < mem_estimate)) {
472             new_estimate = (PetscInt)(1.5*mem_estimate)+1;
473             ierr = PetscMalloc(new_estimate * sizeof(PetscInt),&tmp);CHKERRQ(ierr);
474             ierr = PetscMemcpy(tmp,xdata[0],mem_estimate*sizeof(PetscInt));CHKERRQ(ierr);
475             ierr = PetscFree(xdata[0]);CHKERRQ(ierr);
476             xdata[0]     = tmp;
477             mem_estimate = new_estimate; ++no_malloc;
478             for (ctr=1; ctr<=i; ctr++) { xdata[ctr] = xdata[ctr-1] + isz1[ctr-1];}
479           }
480           xdata[i][ct2++] = row;
481           ct3++;
482         }
483       }
484       for (k=oct2,max2=ct2; k<max2; k++)  {
485         row   = xdata[i][k] - rstart;
486         start = ai[row];
487         end   = ai[row+1];
488         for (l=start; l<end; l++) {
489           val = aj[l] + cstart;
490           if (!PetscBTLookupSet(xtable,val)) {
491             if (!(ct3 < mem_estimate)) {
492               new_estimate = (PetscInt)(1.5*mem_estimate)+1;
493               ierr = PetscMalloc(new_estimate * sizeof(PetscInt),&tmp);CHKERRQ(ierr);
494               ierr = PetscMemcpy(tmp,xdata[0],mem_estimate*sizeof(PetscInt));CHKERRQ(ierr);
495               ierr = PetscFree(xdata[0]);CHKERRQ(ierr);
496               xdata[0]     = tmp;
497               mem_estimate = new_estimate; ++no_malloc;
498               for (ctr=1; ctr<=i; ctr++) { xdata[ctr] = xdata[ctr-1] + isz1[ctr-1];}
499             }
500             xdata[i][ct2++] = val;
501             ct3++;
502           }
503         }
504         start = bi[row];
505         end   = bi[row+1];
506         for (l=start; l<end; l++) {
507           val = garray[bj[l]];
508           if (!PetscBTLookupSet(xtable,val)) {
509             if (!(ct3 < mem_estimate)) {
510               new_estimate = (PetscInt)(1.5*mem_estimate)+1;
511               ierr = PetscMalloc(new_estimate * sizeof(PetscInt),&tmp);CHKERRQ(ierr);
512               ierr = PetscMemcpy(tmp,xdata[0],mem_estimate*sizeof(PetscInt));CHKERRQ(ierr);
513               ierr = PetscFree(xdata[0]);CHKERRQ(ierr);
514               xdata[0]     = tmp;
515               mem_estimate = new_estimate; ++no_malloc;
516               for (ctr =1; ctr <=i; ctr++) { xdata[ctr] = xdata[ctr-1] + isz1[ctr-1];}
517             }
518             xdata[i][ct2++] = val;
519             ct3++;
520           }
521         }
522       }
523       /* Update the header*/
524       xdata[i][2*j]   = ct2 - oct2; /* Undo the vector isz1 and use only a var*/
525       xdata[i][2*j-1] = rbuf_i[2*j-1];
526     }
527     xdata[i][0] = rbuf_0;
528     xdata[i+1]  = xdata[i] + ct2;
529     isz1[i]     = ct2; /* size of each message */
530   }
531   ierr = PetscBTDestroy(&xtable);CHKERRQ(ierr);
532   ierr = PetscInfo3(C,"Allocated %D bytes, required %D, no of mallocs = %D\n",mem_estimate,ct3,no_malloc);CHKERRQ(ierr);
533   PetscFunctionReturn(0);
534 }
535 
536 #undef __FUNCT__
537 #define __FUNCT__ "MatGetSubMatrices_MPIBAIJ"
538 PetscErrorCode MatGetSubMatrices_MPIBAIJ(Mat C,PetscInt ismax,const IS isrow[],const IS iscol[],MatReuse scall,Mat *submat[])
539 {
540   IS             *isrow_new,*iscol_new;
541   Mat_MPIBAIJ    *c = (Mat_MPIBAIJ*)C->data;
542   PetscErrorCode ierr;
543   PetscInt       nmax,nstages_local,nstages,i,pos,max_no,ncol,nrow,N=C->cmap->N,bs=C->rmap->bs;
544   PetscBool      colflag,*allcolumns,*allrows;
545 
546   PetscFunctionBegin;
547   /* Currently, unsorted column indices will result in inverted column indices in the resulting submatrices. */
548   for (i = 0; i < ismax; ++i) {
549     PetscBool sorted;
550     ierr = ISSorted(iscol[i], &sorted);CHKERRQ(ierr);
551     if (!sorted) SETERRQ1(((PetscObject)iscol[i])->comm, PETSC_ERR_SUP, "Column index set %D not sorted", i);
552   }
553   /* The compression and expansion should be avoided. Doesn't point
554      out errors, might change the indices, hence buggey */
555   ierr = PetscMalloc2(ismax+1,IS,&isrow_new,ismax+1,IS,&iscol_new);CHKERRQ(ierr);
556   ierr = ISCompressIndicesGeneral(N,C->rmap->n,bs,ismax,isrow,isrow_new);CHKERRQ(ierr);
557   ierr = ISCompressIndicesGeneral(N,C->cmap->n,bs,ismax,iscol,iscol_new);CHKERRQ(ierr);
558 
559   /* Check for special case: each processor gets entire matrix columns */
560   ierr = PetscMalloc2(ismax+1,PetscBool,&allcolumns,ismax+1,PetscBool,&allrows);CHKERRQ(ierr);
561   for (i=0; i<ismax; i++) {
562     ierr = ISIdentity(iscol[i],&colflag);CHKERRQ(ierr);
563     ierr = ISGetLocalSize(iscol[i],&ncol);CHKERRQ(ierr);
564     if (colflag && ncol == C->cmap->N) {
565       allcolumns[i] = PETSC_TRUE;
566     } else {
567       allcolumns[i] = PETSC_FALSE;
568     }
569 
570     ierr = ISIdentity(isrow[i],&colflag);CHKERRQ(ierr);
571     ierr = ISGetLocalSize(isrow[i],&nrow);CHKERRQ(ierr);
572     if (colflag && nrow == C->rmap->N) {
573       allrows[i] = PETSC_TRUE;
574     } else {
575       allrows[i] = PETSC_FALSE;
576     }
577   }
578 
579   /* Allocate memory to hold all the submatrices */
580   if (scall != MAT_REUSE_MATRIX) {
581     ierr = PetscMalloc((ismax+1)*sizeof(Mat),submat);CHKERRQ(ierr);
582   }
583   /* Determine the number of stages through which submatrices are done */
584   nmax          = 20*1000000 / (c->Nbs * sizeof(PetscInt));
585   if (!nmax) nmax = 1;
586   nstages_local = ismax/nmax + ((ismax % nmax)?1:0);
587 
588   /* Make sure every processor loops through the nstages */
589   ierr = MPI_Allreduce(&nstages_local,&nstages,1,MPIU_INT,MPI_MAX,((PetscObject)C)->comm);CHKERRQ(ierr);
590   for (i=0,pos=0; i<nstages; i++) {
591     if (pos+nmax <= ismax) max_no = nmax;
592     else if (pos == ismax) max_no = 0;
593     else                   max_no = ismax-pos;
594     ierr = MatGetSubMatrices_MPIBAIJ_local(C,max_no,isrow_new+pos,iscol_new+pos,scall,allrows+pos,allcolumns+pos,*submat+pos);CHKERRQ(ierr);
595     pos += max_no;
596   }
597 
598   for (i=0; i<ismax; i++) {
599     ierr = ISDestroy(&isrow_new[i]);CHKERRQ(ierr);
600     ierr = ISDestroy(&iscol_new[i]);CHKERRQ(ierr);
601   }
602   ierr = PetscFree2(isrow_new,iscol_new);CHKERRQ(ierr);
603   ierr = PetscFree2(allcolumns,allrows);CHKERRQ(ierr);
604   PetscFunctionReturn(0);
605 }
606 
607 #if defined (PETSC_USE_CTABLE)
608 #undef __FUNCT__
609 #define __FUNCT__ "PetscGetProc"
610 PetscErrorCode PetscGetProc(const PetscInt row, const PetscMPIInt size, const PetscInt proc_gnode[], PetscMPIInt *rank)
611 {
612   PetscInt    nGlobalNd = proc_gnode[size];
613   PetscMPIInt fproc = PetscMPIIntCast((PetscInt)(((float)row * (float)size / (float)nGlobalNd + 0.5)));
614 
615   PetscFunctionBegin;
616   if (fproc > size) fproc = size;
617   while (row < proc_gnode[fproc] || row >= proc_gnode[fproc+1]) {
618     if (row < proc_gnode[fproc]) fproc--;
619     else                         fproc++;
620   }
621   *rank = fproc;
622   PetscFunctionReturn(0);
623 }
624 #endif
625 
626 /* -------------------------------------------------------------------------*/
627 /* This code is used for BAIJ and SBAIJ matrices (unfortunate dependency) */
628 #undef __FUNCT__
629 #define __FUNCT__ "MatGetSubMatrices_MPIBAIJ_local"
630 PetscErrorCode MatGetSubMatrices_MPIBAIJ_local(Mat C,PetscInt ismax,const IS isrow[],const IS iscol[],MatReuse scall,PetscBool *allrows,PetscBool *allcolumns,Mat *submats)
631 {
632   Mat_MPIBAIJ    *c = (Mat_MPIBAIJ*)C->data;
633   Mat            A = c->A;
634   Mat_SeqBAIJ    *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ*)c->B->data,*mat;
635   const PetscInt **irow,**icol,*irow_i;
636   PetscInt       *nrow,*ncol,*w3,*w4,start;
637   PetscErrorCode ierr;
638   PetscMPIInt    size,tag0,tag1,tag2,tag3,*w1,*w2,nrqr,idex,end,proc;
639   PetscInt       **sbuf1,**sbuf2,rank,i,j,k,l,ct1,ct2,**rbuf1,row;
640   PetscInt       nrqs,msz,**ptr,*req_size,*ctr,*pa,*tmp,tcol;
641   PetscInt       **rbuf3,*req_source,**sbuf_aj,**rbuf2,max1,max2;
642   PetscInt       **lens,is_no,ncols,*cols,mat_i,*mat_j,tmp2,jmax;
643   PetscInt       ctr_j,*sbuf1_j,*sbuf_aj_i,*rbuf1_i,kmax,*lens_i;
644   PetscInt       bs=C->rmap->bs,bs2=c->bs2,*a_j=a->j,*b_j=b->j,*cworkA,*cworkB;
645   PetscInt       cstart = c->cstartbs,nzA,nzB,*a_i=a->i,*b_i=b->i,imark;
646   PetscInt       *bmap = c->garray,ctmp,rstart=c->rstartbs;
647   MPI_Request    *s_waits1,*r_waits1,*s_waits2,*r_waits2,*r_waits3,*s_waits3;
648   MPI_Status     *r_status1,*r_status2,*s_status1,*s_status3,*s_status2,*r_status3;
649   MPI_Comm       comm;
650   PetscBool      flag;
651   PetscMPIInt    *onodes1,*olengths1;
652   PetscBool      ijonly=c->ijonly; /* private flag indicates only matrix data structures are requested */
653   /* variables below are used for the matrix numerical values - case of !ijonly */
654   MPI_Request    *r_waits4,*s_waits4;
655   MPI_Status     *r_status4,*s_status4;
656   MatScalar      **rbuf4,**sbuf_aa,*vals,*mat_a = PETSC_NULL,*sbuf_aa_i,*vworkA = PETSC_NULL,*vworkB = PETSC_NULL;
657   MatScalar      *a_a=a->a,*b_a=b->a;
658 
659 #if defined (PETSC_USE_CTABLE)
660   PetscInt       tt;
661   PetscTable     *rmap,*cmap,rmap_i,cmap_i=PETSC_NULL;
662 #else
663   PetscInt       **cmap,*cmap_i=PETSC_NULL,*rtable,*rmap_i,**rmap, Mbs = c->Mbs;
664 #endif
665 
666   PetscFunctionBegin;
667   comm   = ((PetscObject)C)->comm;
668   tag0   = ((PetscObject)C)->tag;
669   size   = c->size;
670   rank   = c->rank;
671 
672   /* Get some new tags to keep the communication clean */
673   ierr = PetscObjectGetNewTag((PetscObject)C,&tag1);CHKERRQ(ierr);
674   ierr = PetscObjectGetNewTag((PetscObject)C,&tag2);CHKERRQ(ierr);
675   ierr = PetscObjectGetNewTag((PetscObject)C,&tag3);CHKERRQ(ierr);
676 
677 #if defined(PETSC_USE_CTABLE)
678   ierr = PetscMalloc4(ismax,const PetscInt*,&irow,ismax,const PetscInt*,&icol,ismax,PetscInt,&nrow,ismax,PetscInt,&ncol);CHKERRQ(ierr);
679 #else
680   ierr = PetscMalloc5(ismax,const PetscInt*,&irow,ismax,const PetscInt*,&icol,ismax,PetscInt,&nrow,ismax,PetscInt,&ncol,Mbs+1,PetscInt,&rtable);CHKERRQ(ierr);
681   /* Create hash table for the mapping :row -> proc*/
682   for (i=0,j=0; i<size; i++) {
683     jmax = C->rmap->range[i+1]/bs;
684     for (; j<jmax; j++) {
685       rtable[j] = i;
686     }
687   }
688 #endif
689 
690   for (i=0; i<ismax; i++) {
691     if (allrows[i]) {
692       irow[i] = PETSC_NULL;
693       nrow[i] = C->rmap->N/bs;
694     } else {
695       ierr = ISGetIndices(isrow[i],&irow[i]);CHKERRQ(ierr);
696       ierr = ISGetLocalSize(isrow[i],&nrow[i]);CHKERRQ(ierr);
697     }
698 
699     if (allcolumns[i]) {
700       icol[i] = PETSC_NULL;
701       ncol[i] = C->cmap->N/bs;
702     } else {
703       ierr = ISGetIndices(iscol[i],&icol[i]);CHKERRQ(ierr);
704       ierr = ISGetLocalSize(iscol[i],&ncol[i]);CHKERRQ(ierr);
705     }
706   }
707 
708   /* evaluate communication - mesg to who,length of mesg,and buffer space
709      required. Based on this, buffers are allocated, and data copied into them*/
710   ierr = PetscMalloc4(size,PetscMPIInt,&w1,size,PetscMPIInt,&w2,size,PetscInt,&w3,size,PetscInt,&w4);CHKERRQ(ierr);
711   ierr = PetscMemzero(w1,size*sizeof(PetscMPIInt));CHKERRQ(ierr);
712   ierr = PetscMemzero(w2,size*sizeof(PetscMPIInt));CHKERRQ(ierr);
713   ierr = PetscMemzero(w3,size*sizeof(PetscInt));CHKERRQ(ierr);
714   for (i=0; i<ismax; i++) {
715     ierr   = PetscMemzero(w4,size*sizeof(PetscInt));CHKERRQ(ierr); /* initialise work vector*/
716     jmax   = nrow[i];
717     irow_i = irow[i];
718     for (j=0; j<jmax; j++) {
719       if (allrows[i]) {
720         row = j;
721       } else {
722         row  = irow_i[j];
723       }
724 #if defined (PETSC_USE_CTABLE)
725       ierr = PetscGetProc(row,size,c->rangebs,&proc);CHKERRQ(ierr);
726 #else
727       proc = rtable[row];
728 #endif
729       w4[proc]++;
730     }
731     for (j=0; j<size; j++) {
732       if (w4[j]) { w1[j] += w4[j];  w3[j]++;}
733     }
734   }
735 
736   nrqs     = 0;              /* no of outgoing messages */
737   msz      = 0;              /* total mesg length for all proc */
738   w1[rank] = 0;              /* no mesg sent to intself */
739   w3[rank] = 0;
740   for (i=0; i<size; i++) {
741     if (w1[i])  { w2[i] = 1; nrqs++;} /* there exists a message to proc i */
742   }
743   ierr = PetscMalloc((nrqs+1)*sizeof(PetscInt),&pa);CHKERRQ(ierr); /*(proc -array)*/
744   for (i=0,j=0; i<size; i++) {
745     if (w1[i]) { pa[j] = i; j++; }
746   }
747 
748   /* Each message would have a header = 1 + 2*(no of IS) + data */
749   for (i=0; i<nrqs; i++) {
750     j     = pa[i];
751     w1[j] += w2[j] + 2* w3[j];
752     msz   += w1[j];
753   }
754 
755   /* Determine the number of messages to expect, their lengths, from from-ids */
756   ierr = PetscGatherNumberOfMessages(comm,w2,w1,&nrqr);CHKERRQ(ierr);
757   ierr = PetscGatherMessageLengths(comm,nrqs,nrqr,w1,&onodes1,&olengths1);CHKERRQ(ierr);
758 
759   /* Now post the Irecvs corresponding to these messages */
760   ierr = PetscPostIrecvInt(comm,tag0,nrqr,onodes1,olengths1,&rbuf1,&r_waits1);CHKERRQ(ierr);
761 
762   ierr = PetscFree(onodes1);CHKERRQ(ierr);
763   ierr = PetscFree(olengths1);CHKERRQ(ierr);
764 
765   /* Allocate Memory for outgoing messages */
766   ierr = PetscMalloc4(size,PetscInt*,&sbuf1,size,PetscInt*,&ptr,2*msz,PetscInt,&tmp,size,PetscInt,&ctr);CHKERRQ(ierr);
767   ierr = PetscMemzero(sbuf1,size*sizeof(PetscInt*));CHKERRQ(ierr);
768   ierr = PetscMemzero(ptr,size*sizeof(PetscInt*));CHKERRQ(ierr);
769   {
770     PetscInt *iptr = tmp,ict = 0;
771     for (i=0; i<nrqs; i++) {
772       j         = pa[i];
773       iptr     += ict;
774       sbuf1[j]  = iptr;
775       ict       = w1[j];
776     }
777   }
778 
779   /* Form the outgoing messages */
780   /* Initialise the header space */
781   for (i=0; i<nrqs; i++) {
782     j           = pa[i];
783     sbuf1[j][0] = 0;
784     ierr        = PetscMemzero(sbuf1[j]+1,2*w3[j]*sizeof(PetscInt));CHKERRQ(ierr);
785     ptr[j]      = sbuf1[j] + 2*w3[j] + 1;
786   }
787 
788   /* Parse the isrow and copy data into outbuf */
789   for (i=0; i<ismax; i++) {
790     ierr   = PetscMemzero(ctr,size*sizeof(PetscInt));CHKERRQ(ierr);
791     irow_i = irow[i];
792     jmax   = nrow[i];
793     for (j=0; j<jmax; j++) {  /* parse the indices of each IS */
794       if (allrows[i]) {
795         row = j;
796       } else {
797         row  = irow_i[j];
798       }
799 #if defined (PETSC_USE_CTABLE)
800       ierr = PetscGetProc(row,size,c->rangebs,&proc);CHKERRQ(ierr);
801 #else
802       proc = rtable[row];
803 #endif
804       if (proc != rank) { /* copy to the outgoing buf*/
805         ctr[proc]++;
806         *ptr[proc] = row;
807         ptr[proc]++;
808       }
809     }
810     /* Update the headers for the current IS */
811     for (j=0; j<size; j++) { /* Can Optimise this loop too */
812       if ((ctr_j = ctr[j])) {
813         sbuf1_j        = sbuf1[j];
814         k              = ++sbuf1_j[0];
815         sbuf1_j[2*k]   = ctr_j;
816         sbuf1_j[2*k-1] = i;
817       }
818     }
819   }
820 
821   /*  Now  post the sends */
822   ierr = PetscMalloc((nrqs+1)*sizeof(MPI_Request),&s_waits1);CHKERRQ(ierr);
823   for (i=0; i<nrqs; ++i) {
824     j = pa[i];
825     ierr = MPI_Isend(sbuf1[j],w1[j],MPIU_INT,j,tag0,comm,s_waits1+i);CHKERRQ(ierr);
826   }
827 
828   /* Post Recieves to capture the buffer size */
829   ierr     = PetscMalloc((nrqs+1)*sizeof(MPI_Request),&r_waits2);CHKERRQ(ierr);
830   ierr     = PetscMalloc((nrqs+1)*sizeof(PetscInt*),&rbuf2);CHKERRQ(ierr);
831   rbuf2[0] = tmp + msz;
832   for (i=1; i<nrqs; ++i) {
833     j        = pa[i];
834     rbuf2[i] = rbuf2[i-1]+w1[pa[i-1]];
835   }
836   for (i=0; i<nrqs; ++i) {
837     j    = pa[i];
838     ierr = MPI_Irecv(rbuf2[i],w1[j],MPIU_INT,j,tag1,comm,r_waits2+i);CHKERRQ(ierr);
839   }
840 
841   /* Send to other procs the buf size they should allocate */
842 
843   /* Receive messages*/
844   ierr = PetscMalloc((nrqr+1)*sizeof(MPI_Request),&s_waits2);CHKERRQ(ierr);
845   ierr = PetscMalloc((nrqr+1)*sizeof(MPI_Status),&r_status1);CHKERRQ(ierr);
846   ierr = PetscMalloc3(nrqr+1,PetscInt*,&sbuf2,nrqr,PetscInt,&req_size,nrqr,PetscInt,&req_source);CHKERRQ(ierr);
847   {
848     Mat_SeqBAIJ *sA = (Mat_SeqBAIJ*)c->A->data,*sB = (Mat_SeqBAIJ*)c->B->data;
849     PetscInt    *sAi = sA->i,*sBi = sB->i,id,*sbuf2_i;
850 
851     for (i=0; i<nrqr; ++i) {
852       ierr = MPI_Waitany(nrqr,r_waits1,&idex,r_status1+i);CHKERRQ(ierr);
853       req_size[idex] = 0;
854       rbuf1_i         = rbuf1[idex];
855       start           = 2*rbuf1_i[0] + 1;
856       ierr            = MPI_Get_count(r_status1+i,MPIU_INT,&end);CHKERRQ(ierr);
857       ierr            = PetscMalloc(end*sizeof(PetscInt),&sbuf2[idex]);CHKERRQ(ierr);
858       sbuf2_i         = sbuf2[idex];
859       for (j=start; j<end; j++) {
860         id               = rbuf1_i[j] - rstart;
861         ncols            = sAi[id+1] - sAi[id] + sBi[id+1] - sBi[id];
862         sbuf2_i[j]       = ncols;
863         req_size[idex] += ncols;
864       }
865       req_source[idex] = r_status1[i].MPI_SOURCE;
866       /* form the header */
867       sbuf2_i[0]   = req_size[idex];
868       for (j=1; j<start; j++) { sbuf2_i[j] = rbuf1_i[j]; }
869       ierr = MPI_Isend(sbuf2_i,end,MPIU_INT,req_source[idex],tag1,comm,s_waits2+i);CHKERRQ(ierr);
870     }
871   }
872   ierr = PetscFree(r_status1);CHKERRQ(ierr);
873   ierr = PetscFree(r_waits1);CHKERRQ(ierr);
874 
875   /*  recv buffer sizes */
876   /* Receive messages*/
877   ierr = PetscMalloc((nrqs+1)*sizeof(PetscInt*),&rbuf3);CHKERRQ(ierr);
878   ierr = PetscMalloc((nrqs+1)*sizeof(MPI_Request),&r_waits3);CHKERRQ(ierr);
879   ierr = PetscMalloc((nrqs+1)*sizeof(MPI_Status),&r_status2);CHKERRQ(ierr);
880   if (!ijonly) {
881     ierr = PetscMalloc((nrqs+1)*sizeof(MatScalar*),&rbuf4);CHKERRQ(ierr);
882     ierr = PetscMalloc((nrqs+1)*sizeof(MPI_Request),&r_waits4);CHKERRQ(ierr);
883   }
884 
885   for (i=0; i<nrqs; ++i) {
886     ierr = MPI_Waitany(nrqs,r_waits2,&idex,r_status2+i);CHKERRQ(ierr);
887     ierr = PetscMalloc(rbuf2[idex][0]*sizeof(PetscInt),&rbuf3[idex]);CHKERRQ(ierr);
888     ierr = MPI_Irecv(rbuf3[idex],rbuf2[idex][0],MPIU_INT,r_status2[i].MPI_SOURCE,tag2,comm,r_waits3+idex);CHKERRQ(ierr);
889     if (!ijonly) {
890       ierr = PetscMalloc(rbuf2[idex][0]*bs2*sizeof(MatScalar),&rbuf4[idex]);CHKERRQ(ierr);
891       ierr = MPI_Irecv(rbuf4[idex],rbuf2[idex][0]*bs2,MPIU_MATSCALAR,r_status2[i].MPI_SOURCE,tag3,comm,r_waits4+idex);CHKERRQ(ierr);
892     }
893   }
894   ierr = PetscFree(r_status2);CHKERRQ(ierr);
895   ierr = PetscFree(r_waits2);CHKERRQ(ierr);
896 
897   /* Wait on sends1 and sends2 */
898   ierr = PetscMalloc((nrqs+1)*sizeof(MPI_Status),&s_status1);CHKERRQ(ierr);
899   ierr = PetscMalloc((nrqr+1)*sizeof(MPI_Status),&s_status2);CHKERRQ(ierr);
900 
901   if (nrqs) {ierr = MPI_Waitall(nrqs,s_waits1,s_status1);CHKERRQ(ierr);}
902   if (nrqr) {ierr = MPI_Waitall(nrqr,s_waits2,s_status2);CHKERRQ(ierr);}
903   ierr = PetscFree(s_status1);CHKERRQ(ierr);
904   ierr = PetscFree(s_status2);CHKERRQ(ierr);
905   ierr = PetscFree(s_waits1);CHKERRQ(ierr);
906   ierr = PetscFree(s_waits2);CHKERRQ(ierr);
907 
908   /* Now allocate buffers for a->j, and send them off */
909   ierr = PetscMalloc((nrqr+1)*sizeof(PetscInt*),&sbuf_aj);CHKERRQ(ierr);
910   for (i=0,j=0; i<nrqr; i++) j += req_size[i];
911   ierr = PetscMalloc((j+1)*sizeof(PetscInt),&sbuf_aj[0]);CHKERRQ(ierr);
912   for (i=1; i<nrqr; i++)  sbuf_aj[i] = sbuf_aj[i-1] + req_size[i-1];
913 
914   ierr = PetscMalloc((nrqr+1)*sizeof(MPI_Request),&s_waits3);CHKERRQ(ierr);
915   {
916      for (i=0; i<nrqr; i++) {
917       rbuf1_i   = rbuf1[i];
918       sbuf_aj_i = sbuf_aj[i];
919       ct1       = 2*rbuf1_i[0] + 1;
920       ct2       = 0;
921       for (j=1,max1=rbuf1_i[0]; j<=max1; j++) {
922         kmax = rbuf1[i][2*j];
923         for (k=0; k<kmax; k++,ct1++) {
924           row    = rbuf1_i[ct1] - rstart;
925           nzA    = a_i[row+1] - a_i[row];     nzB = b_i[row+1] - b_i[row];
926           ncols  = nzA + nzB;
927           cworkA = a_j + a_i[row]; cworkB = b_j + b_i[row];
928 
929           /* load the column indices for this row into cols*/
930           cols  = sbuf_aj_i + ct2;
931           for (l=0; l<nzB; l++) {
932             if ((ctmp = bmap[cworkB[l]]) < cstart)  cols[l] = ctmp;
933             else break;
934           }
935           imark = l;
936           for (l=0; l<nzA; l++)   cols[imark+l] = cstart + cworkA[l];
937           for (l=imark; l<nzB; l++) cols[nzA+l] = bmap[cworkB[l]];
938           ct2 += ncols;
939         }
940       }
941       ierr = MPI_Isend(sbuf_aj_i,req_size[i],MPIU_INT,req_source[i],tag2,comm,s_waits3+i);CHKERRQ(ierr);
942     }
943   }
944   ierr = PetscMalloc((nrqs+1)*sizeof(MPI_Status),&r_status3);CHKERRQ(ierr);
945   ierr = PetscMalloc((nrqr+1)*sizeof(MPI_Status),&s_status3);CHKERRQ(ierr);
946 
947   /* Allocate buffers for a->a, and send them off */
948   if (!ijonly) {
949     ierr = PetscMalloc((nrqr+1)*sizeof(MatScalar *),&sbuf_aa);CHKERRQ(ierr);
950     for (i=0,j=0; i<nrqr; i++) j += req_size[i];
951     ierr = PetscMalloc((j+1)*bs2*sizeof(MatScalar),&sbuf_aa[0]);CHKERRQ(ierr);
952     for (i=1; i<nrqr; i++)  sbuf_aa[i] = sbuf_aa[i-1] + req_size[i-1]*bs2;
953 
954     ierr = PetscMalloc((nrqr+1)*sizeof(MPI_Request),&s_waits4);CHKERRQ(ierr);
955     {
956       for (i=0; i<nrqr; i++) {
957         rbuf1_i   = rbuf1[i];
958         sbuf_aa_i = sbuf_aa[i];
959         ct1       = 2*rbuf1_i[0]+1;
960         ct2       = 0;
961         for (j=1,max1=rbuf1_i[0]; j<=max1; j++) {
962           kmax = rbuf1_i[2*j];
963           for (k=0; k<kmax; k++,ct1++) {
964             row    = rbuf1_i[ct1] - rstart;
965             nzA    = a_i[row+1] - a_i[row];     nzB = b_i[row+1] - b_i[row];
966             ncols  = nzA + nzB;
967             cworkA = a_j + a_i[row];     cworkB = b_j + b_i[row];
968             vworkA = a_a + a_i[row]*bs2; vworkB = b_a + b_i[row]*bs2;
969 
970             /* load the column values for this row into vals*/
971             vals  = sbuf_aa_i+ct2*bs2;
972             for (l=0; l<nzB; l++) {
973               if ((bmap[cworkB[l]]) < cstart) {
974                 ierr = PetscMemcpy(vals+l*bs2,vworkB+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
975               }
976               else break;
977             }
978             imark = l;
979             for (l=0; l<nzA; l++) {
980               ierr = PetscMemcpy(vals+(imark+l)*bs2,vworkA+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
981             }
982             for (l=imark; l<nzB; l++) {
983               ierr = PetscMemcpy(vals+(nzA+l)*bs2,vworkB+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
984             }
985             ct2 += ncols;
986           }
987         }
988         ierr = MPI_Isend(sbuf_aa_i,req_size[i]*bs2,MPIU_MATSCALAR,req_source[i],tag3,comm,s_waits4+i);CHKERRQ(ierr);
989       }
990     }
991     ierr = PetscMalloc((nrqs+1)*sizeof(MPI_Status),&r_status4);CHKERRQ(ierr);
992     ierr = PetscMalloc((nrqr+1)*sizeof(MPI_Status),&s_status4);CHKERRQ(ierr);
993   }
994   ierr = PetscFree(rbuf1[0]);CHKERRQ(ierr);
995   ierr = PetscFree(rbuf1);CHKERRQ(ierr);
996 
997   /* Form the matrix */
998   /* create col map: global col of C -> local col of submatrices */
999   {
1000     const PetscInt *icol_i;
1001 #if defined (PETSC_USE_CTABLE)
1002     ierr = PetscMalloc((1+ismax)*sizeof(PetscTable),&cmap);CHKERRQ(ierr);
1003     for (i=0; i<ismax; i++) {
1004       if (!allcolumns[i]) {
1005         ierr = PetscTableCreate(ncol[i]+1,c->Nbs+1,&cmap[i]);CHKERRQ(ierr);
1006         jmax   = ncol[i];
1007         icol_i = icol[i];
1008         cmap_i = cmap[i];
1009         for (j=0; j<jmax; j++) {
1010           ierr = PetscTableAdd(cmap_i,icol_i[j]+1,j+1,INSERT_VALUES);CHKERRQ(ierr);
1011         }
1012       } else {
1013         cmap[i] = PETSC_NULL;
1014       }
1015     }
1016 #else
1017     ierr    = PetscMalloc(ismax*sizeof(PetscInt*),&cmap);CHKERRQ(ierr);
1018     for (i=0; i<ismax; i++) {
1019       if (!allcolumns[i]) {
1020         ierr = PetscMalloc(c->Nbs*sizeof(PetscInt),&cmap[i]);CHKERRQ(ierr);
1021         ierr = PetscMemzero(cmap[i],c->Nbs*sizeof(PetscInt));CHKERRQ(ierr);
1022         jmax   = ncol[i];
1023         icol_i = icol[i];
1024         cmap_i = cmap[i];
1025         for (j=0; j<jmax; j++) {
1026           cmap_i[icol_i[j]] = j+1;
1027         }
1028       } else { /* allcolumns[i] */
1029         cmap[i] = PETSC_NULL;
1030       }
1031     }
1032 #endif
1033   }
1034 
1035   /* Create lens which is required for MatCreate... */
1036   for (i=0,j=0; i<ismax; i++) { j += nrow[i]; }
1037   ierr    = PetscMalloc((1+ismax)*sizeof(PetscInt*)+ j*sizeof(PetscInt),&lens);CHKERRQ(ierr);
1038   lens[0] = (PetscInt*)(lens + ismax);
1039   ierr    = PetscMemzero(lens[0],j*sizeof(PetscInt));CHKERRQ(ierr);
1040   for (i=1; i<ismax; i++) { lens[i] = lens[i-1] + nrow[i-1]; }
1041 
1042   /* Update lens from local data */
1043   for (i=0; i<ismax; i++) {
1044     jmax   = nrow[i];
1045     if (!allcolumns[i]) cmap_i = cmap[i];
1046     irow_i = irow[i];
1047     lens_i = lens[i];
1048     for (j=0; j<jmax; j++) {
1049       if (allrows[i]) {
1050         row = j;
1051       } else {
1052         row  = irow_i[j];
1053       }
1054 #if defined (PETSC_USE_CTABLE)
1055       ierr = PetscGetProc(row,size,c->rangebs,&proc);CHKERRQ(ierr);
1056 #else
1057       proc = rtable[row];
1058 #endif
1059       if (proc == rank) {
1060         /* Get indices from matA and then from matB */
1061         row    = row - rstart;
1062         nzA    = a_i[row+1] - a_i[row];     nzB = b_i[row+1] - b_i[row];
1063         cworkA =  a_j + a_i[row]; cworkB = b_j + b_i[row];
1064         if (!allcolumns[i]) {
1065 #if defined (PETSC_USE_CTABLE)
1066           for (k=0; k<nzA; k++) {
1067             ierr = PetscTableFind(cmap_i,cstart+cworkA[k]+1,&tt);CHKERRQ(ierr);
1068             if (tt) { lens_i[j]++; }
1069           }
1070           for (k=0; k<nzB; k++) {
1071             ierr = PetscTableFind(cmap_i,bmap[cworkB[k]]+1,&tt);CHKERRQ(ierr);
1072             if (tt) { lens_i[j]++; }
1073           }
1074 
1075 #else
1076           for (k=0; k<nzA; k++) {
1077             if (cmap_i[cstart + cworkA[k]]) { lens_i[j]++; }
1078           }
1079           for (k=0; k<nzB; k++) {
1080             if (cmap_i[bmap[cworkB[k]]]) { lens_i[j]++; }
1081           }
1082 #endif
1083         } else {/* allcolumns */
1084           lens_i[j] = nzA + nzB;
1085         }
1086       }
1087     }
1088   }
1089 #if defined (PETSC_USE_CTABLE)
1090   /* Create row map*/
1091   ierr = PetscMalloc((1+ismax)*sizeof(PetscTable),&rmap);CHKERRQ(ierr);
1092   for (i=0; i<ismax; i++) {
1093     ierr = PetscTableCreate(nrow[i]+1,c->Mbs+1,&rmap[i]);CHKERRQ(ierr);
1094   }
1095 #else
1096   /* Create row map*/
1097   ierr    = PetscMalloc((1+ismax)*sizeof(PetscInt*)+ ismax*Mbs*sizeof(PetscInt),&rmap);CHKERRQ(ierr);
1098   rmap[0] = (PetscInt*)(rmap + ismax);
1099   ierr    = PetscMemzero(rmap[0],ismax*Mbs*sizeof(PetscInt));CHKERRQ(ierr);
1100   for (i=1; i<ismax; i++) { rmap[i] = rmap[i-1] + Mbs;}
1101 #endif
1102   for (i=0; i<ismax; i++) {
1103     irow_i = irow[i];
1104     jmax   = nrow[i];
1105 #if defined (PETSC_USE_CTABLE)
1106     rmap_i = rmap[i];
1107     for (j=0; j<jmax; j++) {
1108       if (allrows[i]) {
1109         ierr = PetscTableAdd(rmap_i,j+1,j+1,INSERT_VALUES);CHKERRQ(ierr);
1110       } else {
1111         ierr = PetscTableAdd(rmap_i,irow_i[j]+1,j+1,INSERT_VALUES);CHKERRQ(ierr);
1112       }
1113     }
1114 #else
1115     rmap_i = rmap[i];
1116     for (j=0; j<jmax; j++) {
1117       if (allrows[i]) {
1118         rmap_i[j] = j;
1119       } else {
1120         rmap_i[irow_i[j]] = j;
1121       }
1122     }
1123 #endif
1124   }
1125 
1126   /* Update lens from offproc data */
1127   {
1128     PetscInt    *rbuf2_i,*rbuf3_i,*sbuf1_i;
1129     PetscMPIInt ii;
1130 
1131     for (tmp2=0; tmp2<nrqs; tmp2++) {
1132       ierr    = MPI_Waitany(nrqs,r_waits3,&ii,r_status3+tmp2);CHKERRQ(ierr);
1133       idex   = pa[ii];
1134       sbuf1_i = sbuf1[idex];
1135       jmax    = sbuf1_i[0];
1136       ct1     = 2*jmax+1;
1137       ct2     = 0;
1138       rbuf2_i = rbuf2[ii];
1139       rbuf3_i = rbuf3[ii];
1140       for (j=1; j<=jmax; j++) {
1141         is_no   = sbuf1_i[2*j-1];
1142         max1    = sbuf1_i[2*j];
1143         lens_i  = lens[is_no];
1144         if (!allcolumns[is_no]) cmap_i = cmap[is_no];
1145         rmap_i = rmap[is_no];
1146         for (k=0; k<max1; k++,ct1++) {
1147 #if defined (PETSC_USE_CTABLE)
1148           ierr = PetscTableFind(rmap_i,sbuf1_i[ct1]+1,&row);CHKERRQ(ierr);
1149           row--;
1150           if (row < 0) { SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"row not found in table"); }
1151 #else
1152           row  = rmap_i[sbuf1_i[ct1]]; /* the val in the new matrix to be */
1153 #endif
1154           max2 = rbuf2_i[ct1];
1155           for (l=0; l<max2; l++,ct2++) {
1156             if (!allcolumns[is_no]) {
1157 #if defined (PETSC_USE_CTABLE)
1158               ierr = PetscTableFind(cmap_i,rbuf3_i[ct2]+1,&tt);CHKERRQ(ierr);
1159               if (tt) {
1160                 lens_i[row]++;
1161               }
1162 #else
1163               if (cmap_i[rbuf3_i[ct2]]) {
1164                 lens_i[row]++;
1165               }
1166 #endif
1167             } else { /* allcolumns */
1168               lens_i[row]++;
1169             }
1170           }
1171         }
1172       }
1173     }
1174   }
1175   ierr = PetscFree(r_status3);CHKERRQ(ierr);
1176   ierr = PetscFree(r_waits3);CHKERRQ(ierr);
1177   if (nrqr) {ierr = MPI_Waitall(nrqr,s_waits3,s_status3);CHKERRQ(ierr);}
1178   ierr = PetscFree(s_status3);CHKERRQ(ierr);
1179   ierr = PetscFree(s_waits3);CHKERRQ(ierr);
1180 
1181   /* Create the submatrices */
1182   if (scall == MAT_REUSE_MATRIX) {
1183     if (ijonly) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP," MAT_REUSE_MATRIX and ijonly is not supported yet");
1184     /*
1185         Assumes new rows are same length as the old rows, hence bug!
1186     */
1187     for (i=0; i<ismax; i++) {
1188       mat = (Mat_SeqBAIJ *)(submats[i]->data);
1189       if ((mat->mbs != nrow[i]) || (mat->nbs != ncol[i] || C->rmap->bs != bs)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Cannot reuse matrix. wrong size");
1190       ierr = PetscMemcmp(mat->ilen,lens[i],mat->mbs *sizeof(PetscInt),&flag);CHKERRQ(ierr);
1191       if (!flag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_INCOMP,"Cannot reuse matrix. wrong no of nonzeros");
1192       /* Initial matrix as if empty */
1193       ierr = PetscMemzero(mat->ilen,mat->mbs*sizeof(PetscInt));CHKERRQ(ierr);
1194       submats[i]->factortype = C->factortype;
1195     }
1196   } else {
1197     PetscInt bs_tmp;
1198     if (ijonly) {
1199       bs_tmp = 1;
1200     } else {
1201       bs_tmp = bs;
1202     }
1203     for (i=0; i<ismax; i++) {
1204       ierr = MatCreate(PETSC_COMM_SELF,submats+i);CHKERRQ(ierr);
1205       ierr = MatSetSizes(submats[i],nrow[i]*bs_tmp,ncol[i]*bs_tmp,nrow[i]*bs_tmp,ncol[i]*bs_tmp);CHKERRQ(ierr);
1206       ierr = MatSetType(submats[i],((PetscObject)A)->type_name);CHKERRQ(ierr);
1207       ierr = MatSeqBAIJSetPreallocation(submats[i],bs_tmp,0,lens[i]);CHKERRQ(ierr);
1208       ierr = MatSeqSBAIJSetPreallocation(submats[i],bs_tmp,0,lens[i]);CHKERRQ(ierr); /* this subroutine is used by SBAIJ routines */
1209     }
1210   }
1211 
1212   /* Assemble the matrices */
1213   /* First assemble the local rows */
1214   {
1215     PetscInt  ilen_row,*imat_ilen,*imat_j,*imat_i;
1216     MatScalar *imat_a = PETSC_NULL;
1217 
1218     for (i=0; i<ismax; i++) {
1219       mat       = (Mat_SeqBAIJ*)submats[i]->data;
1220       imat_ilen = mat->ilen;
1221       imat_j    = mat->j;
1222       imat_i    = mat->i;
1223       if (!ijonly) imat_a = mat->a;
1224       if (!allcolumns[i]) cmap_i = cmap[i];
1225       rmap_i = rmap[i];
1226       irow_i    = irow[i];
1227       jmax      = nrow[i];
1228       for (j=0; j<jmax; j++) {
1229         if (allrows[i]) {
1230           row = j;
1231         } else {
1232           row      = irow_i[j];
1233         }
1234 #if defined (PETSC_USE_CTABLE)
1235         ierr = PetscGetProc(row,size,c->rangebs,&proc);CHKERRQ(ierr);
1236 #else
1237         proc = rtable[row];
1238 #endif
1239         if (proc == rank) {
1240           row      = row - rstart;
1241           nzA      = a_i[row+1] - a_i[row];
1242           nzB      = b_i[row+1] - b_i[row];
1243           cworkA   = a_j + a_i[row];
1244           cworkB   = b_j + b_i[row];
1245           if (!ijonly) {
1246             vworkA = a_a + a_i[row]*bs2;
1247             vworkB = b_a + b_i[row]*bs2;
1248           }
1249 #if defined (PETSC_USE_CTABLE)
1250           ierr = PetscTableFind(rmap_i,row+rstart+1,&row);CHKERRQ(ierr);
1251           row--;
1252           if (row < 0) { SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"row not found in table"); }
1253 #else
1254           row      = rmap_i[row + rstart];
1255 #endif
1256           mat_i    = imat_i[row];
1257           if (!ijonly) mat_a = imat_a + mat_i*bs2;
1258           mat_j    = imat_j + mat_i;
1259           ilen_row = imat_ilen[row];
1260 
1261           /* load the column indices for this row into cols*/
1262           if (!allcolumns[i]) {
1263             for (l=0; l<nzB; l++) {
1264               if ((ctmp = bmap[cworkB[l]]) < cstart) {
1265 #if defined (PETSC_USE_CTABLE)
1266                 ierr = PetscTableFind(cmap_i,ctmp+1,&tcol);CHKERRQ(ierr);
1267                 if (tcol) {
1268 #else
1269                 if ((tcol = cmap_i[ctmp])) {
1270 #endif
1271                   *mat_j++ = tcol - 1;
1272                   ierr     = PetscMemcpy(mat_a,vworkB+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
1273                   mat_a   += bs2;
1274                   ilen_row++;
1275                 }
1276               } else break;
1277             }
1278             imark = l;
1279             for (l=0; l<nzA; l++) {
1280 #if defined (PETSC_USE_CTABLE)
1281               ierr = PetscTableFind(cmap_i,cstart+cworkA[l]+1,&tcol);CHKERRQ(ierr);
1282               if (tcol) {
1283 #else
1284               if ((tcol = cmap_i[cstart + cworkA[l]])) {
1285 #endif
1286                 *mat_j++ = tcol - 1;
1287                 if (!ijonly) {
1288                   ierr   = PetscMemcpy(mat_a,vworkA+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
1289                   mat_a += bs2;
1290                 }
1291                 ilen_row++;
1292               }
1293             }
1294             for (l=imark; l<nzB; l++) {
1295 #if defined (PETSC_USE_CTABLE)
1296               ierr = PetscTableFind(cmap_i,bmap[cworkB[l]]+1,&tcol);CHKERRQ(ierr);
1297               if (tcol) {
1298 #else
1299               if ((tcol = cmap_i[bmap[cworkB[l]]])) {
1300 #endif
1301                 *mat_j++ = tcol - 1;
1302                 if (!ijonly) {
1303                   ierr     = PetscMemcpy(mat_a,vworkB+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
1304                   mat_a   += bs2;
1305                 }
1306                 ilen_row++;
1307               }
1308             }
1309           } else { /* allcolumns */
1310             for (l=0; l<nzB; l++) {
1311               if ((ctmp = bmap[cworkB[l]]) < cstart) {
1312                 *mat_j++ = ctmp;
1313                 ierr     = PetscMemcpy(mat_a,vworkB+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
1314                 mat_a   += bs2;
1315                 ilen_row++;
1316               } else break;
1317             }
1318             imark = l;
1319             for (l=0; l<nzA; l++) {
1320               *mat_j++ = cstart+cworkA[l];
1321               if (!ijonly) {
1322                 ierr   = PetscMemcpy(mat_a,vworkA+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
1323                 mat_a += bs2;
1324               }
1325               ilen_row++;
1326             }
1327             for (l=imark; l<nzB; l++) {
1328               *mat_j++ = bmap[cworkB[l]];
1329               if (!ijonly) {
1330                 ierr     = PetscMemcpy(mat_a,vworkB+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
1331                 mat_a   += bs2;
1332               }
1333               ilen_row++;
1334             }
1335           }
1336           imat_ilen[row] = ilen_row;
1337         }
1338       }
1339     }
1340   }
1341 
1342   /*   Now assemble the off proc rows*/
1343   {
1344     PetscInt    *sbuf1_i,*rbuf2_i,*rbuf3_i,*imat_ilen,ilen;
1345     PetscInt    *imat_j,*imat_i;
1346     MatScalar   *imat_a = PETSC_NULL,*rbuf4_i = PETSC_NULL;
1347     PetscMPIInt ii;
1348 
1349     for (tmp2=0; tmp2<nrqs; tmp2++) {
1350       if (ijonly) {
1351         ii = tmp2;
1352       } else {
1353         ierr = MPI_Waitany(nrqs,r_waits4,&ii,r_status4+tmp2);CHKERRQ(ierr);
1354       }
1355       idex   = pa[ii];
1356       sbuf1_i = sbuf1[idex];
1357       jmax    = sbuf1_i[0];
1358       ct1     = 2*jmax + 1;
1359       ct2     = 0;
1360       rbuf2_i = rbuf2[ii];
1361       rbuf3_i = rbuf3[ii];
1362       if (!ijonly) rbuf4_i = rbuf4[ii];
1363       for (j=1; j<=jmax; j++) {
1364         is_no     = sbuf1_i[2*j-1];
1365         if (!allcolumns[is_no]) cmap_i = cmap[is_no];
1366         rmap_i    = rmap[is_no];
1367         mat       = (Mat_SeqBAIJ*)submats[is_no]->data;
1368         imat_ilen = mat->ilen;
1369         imat_j    = mat->j;
1370         imat_i    = mat->i;
1371         if (!ijonly) imat_a = mat->a;
1372         max1      = sbuf1_i[2*j];
1373         for (k=0; k<max1; k++,ct1++) {
1374           row   = sbuf1_i[ct1];
1375 #if defined (PETSC_USE_CTABLE)
1376           ierr = PetscTableFind(rmap_i,row+1,&row);CHKERRQ(ierr);
1377           row--;
1378           if (row < 0) { SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"row not found in table"); }
1379 #else
1380           row   = rmap_i[row];
1381 #endif
1382           ilen  = imat_ilen[row];
1383           mat_i = imat_i[row];
1384           if (!ijonly) mat_a = imat_a + mat_i*bs2;
1385           mat_j = imat_j + mat_i;
1386           max2 = rbuf2_i[ct1];
1387 
1388           if (!allcolumns[is_no]) {
1389             for (l=0; l<max2; l++,ct2++) {
1390 #if defined (PETSC_USE_CTABLE)
1391               ierr = PetscTableFind(cmap_i,rbuf3_i[ct2]+1,&tcol);CHKERRQ(ierr);
1392               if (tcol) {
1393 #else
1394               if ((tcol = cmap_i[rbuf3_i[ct2]])) {
1395 #endif
1396                 *mat_j++    = tcol - 1;
1397                 if (!ijonly) {
1398                   ierr   = PetscMemcpy(mat_a,rbuf4_i+ct2*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
1399                   mat_a += bs2;
1400                 }
1401                 ilen++;
1402               }
1403             }
1404           } else { /* allcolumns */
1405             for (l=0; l<max2; l++,ct2++) {
1406               *mat_j++    = rbuf3_i[ct2];
1407               if (!ijonly) {
1408                 ierr   = PetscMemcpy(mat_a,rbuf4_i+ct2*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
1409                 mat_a += bs2;
1410               }
1411               ilen++;
1412             }
1413           }
1414           imat_ilen[row] = ilen;
1415         }
1416       }
1417     }
1418   }
1419   if (!ijonly) {
1420     ierr = PetscFree(r_status4);CHKERRQ(ierr);
1421     ierr = PetscFree(r_waits4);CHKERRQ(ierr);
1422     if (nrqr) {ierr = MPI_Waitall(nrqr,s_waits4,s_status4);CHKERRQ(ierr);}
1423     ierr = PetscFree(s_waits4);CHKERRQ(ierr);
1424     ierr = PetscFree(s_status4);CHKERRQ(ierr);
1425   }
1426 
1427   /* Restore the indices */
1428   for (i=0; i<ismax; i++) {
1429     if (!allrows[i]) {
1430       ierr = ISRestoreIndices(isrow[i],irow+i);CHKERRQ(ierr);
1431     }
1432     if (!allcolumns[i]) {
1433       ierr = ISRestoreIndices(iscol[i],icol+i);CHKERRQ(ierr);
1434     }
1435   }
1436 
1437   /* Destroy allocated memory */
1438 #if defined(PETSC_USE_CTABLE)
1439   ierr = PetscFree4(irow,icol,nrow,ncol);CHKERRQ(ierr);
1440 #else
1441   ierr = PetscFree5(irow,icol,nrow,ncol,rtable);CHKERRQ(ierr);
1442 #endif
1443   ierr = PetscFree4(w1,w2,w3,w4);CHKERRQ(ierr);
1444   ierr = PetscFree(pa);CHKERRQ(ierr);
1445 
1446   ierr = PetscFree4(sbuf1,ptr,tmp,ctr);CHKERRQ(ierr);
1447   ierr = PetscFree(sbuf1);CHKERRQ(ierr);
1448   ierr = PetscFree(rbuf2);CHKERRQ(ierr);
1449   for (i=0; i<nrqr; ++i) {
1450     ierr = PetscFree(sbuf2[i]);CHKERRQ(ierr);
1451   }
1452   for (i=0; i<nrqs; ++i) {
1453     ierr = PetscFree(rbuf3[i]);CHKERRQ(ierr);
1454   }
1455   ierr = PetscFree3(sbuf2,req_size,req_source);CHKERRQ(ierr);
1456   ierr = PetscFree(rbuf3);CHKERRQ(ierr);
1457   ierr = PetscFree(sbuf_aj[0]);CHKERRQ(ierr);
1458   ierr = PetscFree(sbuf_aj);CHKERRQ(ierr);
1459   if (!ijonly) {
1460     for (i=0; i<nrqs; ++i) {ierr = PetscFree(rbuf4[i]);CHKERRQ(ierr);}
1461     ierr = PetscFree(rbuf4);CHKERRQ(ierr);
1462     ierr = PetscFree(sbuf_aa[0]);CHKERRQ(ierr);
1463     ierr = PetscFree(sbuf_aa);CHKERRQ(ierr);
1464   }
1465 
1466 #if defined (PETSC_USE_CTABLE)
1467   for (i=0; i<ismax; i++) {
1468     ierr = PetscTableDestroy((PetscTable*)&rmap[i]);CHKERRQ(ierr);
1469   }
1470 #endif
1471   ierr = PetscFree(rmap);CHKERRQ(ierr);
1472 
1473   for (i=0; i<ismax; i++) {
1474     if (!allcolumns[i]) {
1475 #if defined (PETSC_USE_CTABLE)
1476       ierr = PetscTableDestroy((PetscTable*)&cmap[i]);CHKERRQ(ierr);
1477 #else
1478       ierr = PetscFree(cmap[i]);CHKERRQ(ierr);
1479 #endif
1480     }
1481   }
1482   ierr = PetscFree(cmap);CHKERRQ(ierr);
1483   ierr = PetscFree(lens);CHKERRQ(ierr);
1484 
1485   for (i=0; i<ismax; i++) {
1486     ierr = MatAssemblyBegin(submats[i],MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1487     ierr = MatAssemblyEnd(submats[i],MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1488   }
1489 
1490   c->ijonly = PETSC_FALSE; /* set back to the default */
1491   PetscFunctionReturn(0);
1492 }
1493 
1494