xref: /petsc/src/mat/impls/baij/mpi/baijov.c (revision 17df9f7c95b0ef00153aa5f4903b08e2f3467d6b)
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 PetscErrorCode MatIncreaseOverlap_MPIBAIJ(Mat C,PetscInt imax,IS is[],PetscInt ov)
15 {
16   PetscErrorCode ierr;
17   PetscInt       i,N=C->cmap->N, bs=C->rmap->bs;
18   IS             *is_new;
19 
20   PetscFunctionBegin;
21   ierr = PetscMalloc1(imax,&is_new);CHKERRQ(ierr);
22   /* Convert the indices into block format */
23   ierr = ISCompressIndicesGeneral(N,C->rmap->n,bs,imax,is,is_new);CHKERRQ(ierr);
24   if (ov < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Negative overlap specified\n");
25   for (i=0; i<ov; ++i) {
26     ierr = MatIncreaseOverlap_MPIBAIJ_Once(C,imax,is_new);CHKERRQ(ierr);
27   }
28   for (i=0; i<imax; i++) {ierr = ISDestroy(&is[i]);CHKERRQ(ierr);}
29   ierr = ISExpandIndicesGeneral(N,N,bs,imax,is_new,is);CHKERRQ(ierr);
30   for (i=0; i<imax; i++) {ierr = ISDestroy(&is_new[i]);CHKERRQ(ierr);}
31   ierr = PetscFree(is_new);CHKERRQ(ierr);
32   PetscFunctionReturn(0);
33 }
34 
35 /*
36   Sample message format:
37   If a processor A wants processor B to process some elements corresponding
38   to index sets is[1], is[5]
39   mesg [0] = 2   (no of index sets in the mesg)
40   -----------
41   mesg [1] = 1 => is[1]
42   mesg [2] = sizeof(is[1]);
43   -----------
44   mesg [5] = 5  => is[5]
45   mesg [6] = sizeof(is[5]);
46   -----------
47   mesg [7]
48   mesg [n]  data(is[1])
49   -----------
50   mesg[n+1]
51   mesg[m]  data(is[5])
52   -----------
53 
54   Notes:
55   nrqs - no of requests sent (or to be sent out)
56   nrqr - no of requests recieved (which have to be or which have been processed
57 */
58 PetscErrorCode MatIncreaseOverlap_MPIBAIJ_Once(Mat C,PetscInt imax,IS is[])
59 {
60   Mat_MPIBAIJ    *c = (Mat_MPIBAIJ*)C->data;
61   const PetscInt **idx,*idx_i;
62   PetscInt       *n,*w3,*w4,**data,len;
63   PetscErrorCode ierr;
64   PetscMPIInt    size,rank,tag1,tag2,*w2,*w1,nrqr;
65   PetscInt       Mbs,i,j,k,**rbuf,row,proc=-1,nrqs,msz,**outdat,**ptr;
66   PetscInt       *ctr,*pa,*tmp,*isz,*isz1,**xdata,**rbuf2,*d_p;
67   PetscMPIInt    *onodes1,*olengths1,*onodes2,*olengths2;
68   PetscBT        *table;
69   MPI_Comm       comm;
70   MPI_Request    *s_waits1,*r_waits1,*s_waits2,*r_waits2;
71   MPI_Status     *s_status,*recv_status;
72   char           *t_p;
73 
74   PetscFunctionBegin;
75   ierr = PetscObjectGetComm((PetscObject)C,&comm);CHKERRQ(ierr);
76   size = c->size;
77   rank = c->rank;
78   Mbs  = c->Mbs;
79 
80   ierr = PetscObjectGetNewTag((PetscObject)C,&tag1);CHKERRQ(ierr);
81   ierr = PetscObjectGetNewTag((PetscObject)C,&tag2);CHKERRQ(ierr);
82 
83   ierr = PetscMalloc2(imax+1,&idx,imax,&n);CHKERRQ(ierr);
84 
85   for (i=0; i<imax; i++) {
86     ierr = ISGetIndices(is[i],&idx[i]);CHKERRQ(ierr);
87     ierr = ISGetLocalSize(is[i],&n[i]);CHKERRQ(ierr);
88   }
89 
90   /* evaluate communication - mesg to who,length of mesg, and buffer space
91      required. Based on this, buffers are allocated, and data copied into them*/
92   ierr = PetscCalloc4(size,&w1,size,&w2,size,&w3,size,&w4);CHKERRQ(ierr);
93   for (i=0; i<imax; i++) {
94     ierr  = PetscMemzero(w4,size*sizeof(PetscInt));CHKERRQ(ierr); /* initialise work vector*/
95     idx_i = idx[i];
96     len   = n[i];
97     for (j=0; j<len; j++) {
98       row = idx_i[j];
99       if (row < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Index set cannot have negative entries");
100       ierr = PetscLayoutFindOwner(C->rmap,row*C->rmap->bs,&proc);CHKERRQ(ierr);
101       w4[proc]++;
102     }
103     for (j=0; j<size; j++) {
104       if (w4[j]) { w1[j] += w4[j]; w3[j]++;}
105     }
106   }
107 
108   nrqs     = 0;              /* no of outgoing messages */
109   msz      = 0;              /* total mesg length (for all proc */
110   w1[rank] = 0;              /* no mesg sent to itself */
111   w3[rank] = 0;
112   for (i=0; i<size; i++) {
113     if (w1[i])  {w2[i] = 1; nrqs++;} /* there exists a message to proc i */
114   }
115   /* pa - is list of processors to communicate with */
116   ierr = PetscMalloc1(nrqs+1,&pa);CHKERRQ(ierr);
117   for (i=0,j=0; i<size; i++) {
118     if (w1[i]) {pa[j] = i; j++;}
119   }
120 
121   /* Each message would have a header = 1 + 2*(no of IS) + data */
122   for (i=0; i<nrqs; i++) {
123     j      = pa[i];
124     w1[j] += w2[j] + 2*w3[j];
125     msz   += w1[j];
126   }
127 
128   /* Determine the number of messages to expect, their lengths, from from-ids */
129   ierr = PetscGatherNumberOfMessages(comm,w2,w1,&nrqr);CHKERRQ(ierr);
130   ierr = PetscGatherMessageLengths(comm,nrqs,nrqr,w1,&onodes1,&olengths1);CHKERRQ(ierr);
131 
132   /* Now post the Irecvs corresponding to these messages */
133   ierr = PetscPostIrecvInt(comm,tag1,nrqr,onodes1,olengths1,&rbuf,&r_waits1);CHKERRQ(ierr);
134 
135   /* Allocate Memory for outgoing messages */
136   ierr = PetscMalloc4(size,&outdat,size,&ptr,msz,&tmp,size,&ctr);CHKERRQ(ierr);
137   ierr = PetscMemzero(outdat,size*sizeof(PetscInt*));CHKERRQ(ierr);
138   ierr = PetscMemzero(ptr,size*sizeof(PetscInt*));CHKERRQ(ierr);
139   {
140     PetscInt *iptr = tmp,ict  = 0;
141     for (i=0; i<nrqs; i++) {
142       j         = pa[i];
143       iptr     +=  ict;
144       outdat[j] = iptr;
145       ict       = w1[j];
146     }
147   }
148 
149   /* Form the outgoing messages */
150   /*plug in the headers*/
151   for (i=0; i<nrqs; i++) {
152     j            = pa[i];
153     outdat[j][0] = 0;
154     ierr         = PetscMemzero(outdat[j]+1,2*w3[j]*sizeof(PetscInt));CHKERRQ(ierr);
155     ptr[j]       = outdat[j] + 2*w3[j] + 1;
156   }
157 
158   /* Memory for doing local proc's work*/
159   {
160     ierr = PetscCalloc5(imax,&table, imax,&data, imax,&isz, Mbs*imax,&d_p, (Mbs/PETSC_BITS_PER_BYTE+1)*imax,&t_p);CHKERRQ(ierr);
161 
162     for (i=0; i<imax; i++) {
163       table[i] = t_p + (Mbs/PETSC_BITS_PER_BYTE+1)*i;
164       data[i]  = d_p + (Mbs)*i;
165     }
166   }
167 
168   /* Parse the IS and update local tables and the outgoing buf with the data*/
169   {
170     PetscInt n_i,*data_i,isz_i,*outdat_j,ctr_j;
171     PetscBT  table_i;
172 
173     for (i=0; i<imax; i++) {
174       ierr    = PetscMemzero(ctr,size*sizeof(PetscInt));CHKERRQ(ierr);
175       n_i     = n[i];
176       table_i = table[i];
177       idx_i   = idx[i];
178       data_i  = data[i];
179       isz_i   = isz[i];
180       for (j=0; j<n_i; j++) {   /* parse the indices of each IS */
181         row  = idx_i[j];
182         ierr = PetscLayoutFindOwner(C->rmap,row*C->rmap->bs,&proc);CHKERRQ(ierr);
183         if (proc != rank) { /* copy to the outgoing buffer */
184           ctr[proc]++;
185           *ptr[proc] = row;
186           ptr[proc]++;
187         } else { /* Update the local table */
188           if (!PetscBTLookupSet(table_i,row)) data_i[isz_i++] = row;
189         }
190       }
191       /* Update the headers for the current IS */
192       for (j=0; j<size; j++) { /* Can Optimise this loop by using pa[] */
193         if ((ctr_j = ctr[j])) {
194           outdat_j        = outdat[j];
195           k               = ++outdat_j[0];
196           outdat_j[2*k]   = ctr_j;
197           outdat_j[2*k-1] = i;
198         }
199       }
200       isz[i] = isz_i;
201     }
202   }
203 
204   /*  Now  post the sends */
205   ierr = PetscMalloc1(nrqs+1,&s_waits1);CHKERRQ(ierr);
206   for (i=0; i<nrqs; ++i) {
207     j    = pa[i];
208     ierr = MPI_Isend(outdat[j],w1[j],MPIU_INT,j,tag1,comm,s_waits1+i);CHKERRQ(ierr);
209   }
210 
211   /* No longer need the original indices*/
212   for (i=0; i<imax; ++i) {
213     ierr = ISRestoreIndices(is[i],idx+i);CHKERRQ(ierr);
214   }
215   ierr = PetscFree2(idx,n);CHKERRQ(ierr);
216 
217   for (i=0; i<imax; ++i) {
218     ierr = ISDestroy(&is[i]);CHKERRQ(ierr);
219   }
220 
221   /* Do Local work*/
222   ierr = MatIncreaseOverlap_MPIBAIJ_Local(C,imax,table,isz,data);CHKERRQ(ierr);
223 
224   /* Receive messages*/
225   ierr = PetscMalloc1(nrqr+1,&recv_status);CHKERRQ(ierr);
226   if (nrqr) {ierr = MPI_Waitall(nrqr,r_waits1,recv_status);CHKERRQ(ierr);}
227 
228   ierr = PetscMalloc1(nrqs+1,&s_status);CHKERRQ(ierr);
229   if (nrqs) {ierr = MPI_Waitall(nrqs,s_waits1,s_status);CHKERRQ(ierr);}
230 
231   /* Phase 1 sends are complete - deallocate buffers */
232   ierr = PetscFree4(outdat,ptr,tmp,ctr);CHKERRQ(ierr);
233   ierr = PetscFree4(w1,w2,w3,w4);CHKERRQ(ierr);
234 
235   ierr = PetscMalloc1(nrqr+1,&xdata);CHKERRQ(ierr);
236   ierr = PetscMalloc1(nrqr+1,&isz1);CHKERRQ(ierr);
237   ierr = MatIncreaseOverlap_MPIBAIJ_Receive(C,nrqr,rbuf,xdata,isz1);CHKERRQ(ierr);
238   ierr = PetscFree(rbuf[0]);CHKERRQ(ierr);
239   ierr = PetscFree(rbuf);CHKERRQ(ierr);
240 
241   /* Send the data back*/
242   /* Do a global reduction to know the buffer space req for incoming messages*/
243   {
244     PetscMPIInt *rw1;
245 
246     ierr = PetscCalloc1(size,&rw1);CHKERRQ(ierr);
247 
248     for (i=0; i<nrqr; ++i) {
249       proc = recv_status[i].MPI_SOURCE;
250       if (proc != onodes1[i]) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"MPI_SOURCE mismatch");
251       rw1[proc] = isz1[i];
252     }
253 
254     ierr = PetscFree(onodes1);CHKERRQ(ierr);
255     ierr = PetscFree(olengths1);CHKERRQ(ierr);
256 
257     /* Determine the number of messages to expect, their lengths, from from-ids */
258     ierr = PetscGatherMessageLengths(comm,nrqr,nrqs,rw1,&onodes2,&olengths2);CHKERRQ(ierr);
259     ierr = PetscFree(rw1);CHKERRQ(ierr);
260   }
261   /* Now post the Irecvs corresponding to these messages */
262   ierr = PetscPostIrecvInt(comm,tag2,nrqs,onodes2,olengths2,&rbuf2,&r_waits2);CHKERRQ(ierr);
263 
264   /*  Now  post the sends */
265   ierr = PetscMalloc1(nrqr+1,&s_waits2);CHKERRQ(ierr);
266   for (i=0; i<nrqr; ++i) {
267     j    = recv_status[i].MPI_SOURCE;
268     ierr = MPI_Isend(xdata[i],isz1[i],MPIU_INT,j,tag2,comm,s_waits2+i);CHKERRQ(ierr);
269   }
270 
271   /* receive work done on other processors*/
272   {
273     PetscMPIInt idex;
274     PetscInt    is_no,ct1,max,*rbuf2_i,isz_i,*data_i,jmax;
275     PetscBT     table_i;
276     MPI_Status  *status2;
277 
278     ierr = PetscMalloc1(PetscMax(nrqr,nrqs)+1,&status2);CHKERRQ(ierr);
279     for (i=0; i<nrqs; ++i) {
280       ierr = MPI_Waitany(nrqs,r_waits2,&idex,status2+i);CHKERRQ(ierr);
281       /* Process the message*/
282       rbuf2_i = rbuf2[idex];
283       ct1     = 2*rbuf2_i[0]+1;
284       jmax    = rbuf2[idex][0];
285       for (j=1; j<=jmax; j++) {
286         max     = rbuf2_i[2*j];
287         is_no   = rbuf2_i[2*j-1];
288         isz_i   = isz[is_no];
289         data_i  = data[is_no];
290         table_i = table[is_no];
291         for (k=0; k<max; k++,ct1++) {
292           row = rbuf2_i[ct1];
293           if (!PetscBTLookupSet(table_i,row)) data_i[isz_i++] = row;
294         }
295         isz[is_no] = isz_i;
296       }
297     }
298     if (nrqr) {ierr = MPI_Waitall(nrqr,s_waits2,status2);CHKERRQ(ierr);}
299     ierr = PetscFree(status2);CHKERRQ(ierr);
300   }
301 
302   for (i=0; i<imax; ++i) {
303     ierr = ISCreateGeneral(PETSC_COMM_SELF,isz[i],data[i],PETSC_COPY_VALUES,is+i);CHKERRQ(ierr);
304   }
305 
306 
307   ierr = PetscFree(onodes2);CHKERRQ(ierr);
308   ierr = PetscFree(olengths2);CHKERRQ(ierr);
309 
310   ierr = PetscFree(pa);CHKERRQ(ierr);
311   ierr = PetscFree(rbuf2[0]);CHKERRQ(ierr);
312   ierr = PetscFree(rbuf2);CHKERRQ(ierr);
313   ierr = PetscFree(s_waits1);CHKERRQ(ierr);
314   ierr = PetscFree(r_waits1);CHKERRQ(ierr);
315   ierr = PetscFree(s_waits2);CHKERRQ(ierr);
316   ierr = PetscFree(r_waits2);CHKERRQ(ierr);
317   ierr = PetscFree5(table,data,isz,d_p,t_p);CHKERRQ(ierr);
318   ierr = PetscFree(s_status);CHKERRQ(ierr);
319   ierr = PetscFree(recv_status);CHKERRQ(ierr);
320   ierr = PetscFree(xdata[0]);CHKERRQ(ierr);
321   ierr = PetscFree(xdata);CHKERRQ(ierr);
322   ierr = PetscFree(isz1);CHKERRQ(ierr);
323   PetscFunctionReturn(0);
324 }
325 
326 /*
327    MatIncreaseOverlap_MPIBAIJ_Local - Called by MatincreaseOverlap, to do
328        the work on the local processor.
329 
330      Inputs:
331       C      - MAT_MPIBAIJ;
332       imax - total no of index sets processed at a time;
333       table  - an array of char - size = Mbs bits.
334 
335      Output:
336       isz    - array containing the count of the solution elements corresponding
337                to each index set;
338       data   - pointer to the solutions
339 */
340 static PetscErrorCode MatIncreaseOverlap_MPIBAIJ_Local(Mat C,PetscInt imax,PetscBT *table,PetscInt *isz,PetscInt **data)
341 {
342   Mat_MPIBAIJ *c = (Mat_MPIBAIJ*)C->data;
343   Mat         A  = c->A,B = c->B;
344   Mat_SeqBAIJ *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ*)B->data;
345   PetscInt    start,end,val,max,rstart,cstart,*ai,*aj;
346   PetscInt    *bi,*bj,*garray,i,j,k,row,*data_i,isz_i;
347   PetscBT     table_i;
348 
349   PetscFunctionBegin;
350   rstart = c->rstartbs;
351   cstart = c->cstartbs;
352   ai     = a->i;
353   aj     = a->j;
354   bi     = b->i;
355   bj     = b->j;
356   garray = c->garray;
357 
358 
359   for (i=0; i<imax; i++) {
360     data_i  = data[i];
361     table_i = table[i];
362     isz_i   = isz[i];
363     for (j=0,max=isz[i]; j<max; j++) {
364       row   = data_i[j] - rstart;
365       start = ai[row];
366       end   = ai[row+1];
367       for (k=start; k<end; k++) { /* Amat */
368         val = aj[k] + cstart;
369         if (!PetscBTLookupSet(table_i,val)) data_i[isz_i++] = val;
370       }
371       start = bi[row];
372       end   = bi[row+1];
373       for (k=start; k<end; k++) { /* Bmat */
374         val = garray[bj[k]];
375         if (!PetscBTLookupSet(table_i,val)) data_i[isz_i++] = val;
376       }
377     }
378     isz[i] = isz_i;
379   }
380   PetscFunctionReturn(0);
381 }
382 /*
383       MatIncreaseOverlap_MPIBAIJ_Receive - Process the recieved messages,
384          and return the output
385 
386          Input:
387            C    - the matrix
388            nrqr - no of messages being processed.
389            rbuf - an array of pointers to the recieved requests
390 
391          Output:
392            xdata - array of messages to be sent back
393            isz1  - size of each message
394 
395   For better efficiency perhaps we should malloc separately each xdata[i],
396 then if a remalloc is required we need only copy the data for that one row
397 rather than all previous rows as it is now where a single large chunck of
398 memory is used.
399 
400 */
401 static PetscErrorCode MatIncreaseOverlap_MPIBAIJ_Receive(Mat C,PetscInt nrqr,PetscInt **rbuf,PetscInt **xdata,PetscInt * isz1)
402 {
403   Mat_MPIBAIJ    *c = (Mat_MPIBAIJ*)C->data;
404   Mat            A  = c->A,B = c->B;
405   Mat_SeqBAIJ    *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ*)B->data;
406   PetscErrorCode ierr;
407   PetscInt       rstart,cstart,*ai,*aj,*bi,*bj,*garray,i,j,k;
408   PetscInt       row,total_sz,ct,ct1,ct2,ct3,mem_estimate,oct2,l,start,end;
409   PetscInt       val,max1,max2,Mbs,no_malloc =0,*tmp,new_estimate,ctr;
410   PetscInt       *rbuf_i,kmax,rbuf_0;
411   PetscBT        xtable;
412 
413   PetscFunctionBegin;
414   Mbs    = c->Mbs;
415   rstart = c->rstartbs;
416   cstart = c->cstartbs;
417   ai     = a->i;
418   aj     = a->j;
419   bi     = b->i;
420   bj     = b->j;
421   garray = c->garray;
422 
423 
424   for (i=0,ct=0,total_sz=0; i<nrqr; ++i) {
425     rbuf_i =  rbuf[i];
426     rbuf_0 =  rbuf_i[0];
427     ct    += rbuf_0;
428     for (j=1; j<=rbuf_0; j++) total_sz += rbuf_i[2*j];
429   }
430 
431   if (c->Mbs) max1 = ct*(a->nz +b->nz)/c->Mbs;
432   else        max1 = 1;
433   mem_estimate = 3*((total_sz > max1 ? total_sz : max1)+1);
434   ierr         = PetscMalloc1(mem_estimate,&xdata[0]);CHKERRQ(ierr);
435   ++no_malloc;
436   ierr = PetscBTCreate(Mbs,&xtable);CHKERRQ(ierr);
437   ierr = PetscMemzero(isz1,nrqr*sizeof(PetscInt));CHKERRQ(ierr);
438 
439   ct3 = 0;
440   for (i=0; i<nrqr; i++) { /* for easch mesg from proc i */
441     rbuf_i =  rbuf[i];
442     rbuf_0 =  rbuf_i[0];
443     ct1    =  2*rbuf_0+1;
444     ct2    =  ct1;
445     ct3   += ct1;
446     for (j=1; j<=rbuf_0; j++) { /* for each IS from proc i*/
447       ierr = PetscBTMemzero(Mbs,xtable);CHKERRQ(ierr);
448       oct2 = ct2;
449       kmax = rbuf_i[2*j];
450       for (k=0; k<kmax; k++,ct1++) {
451         row = rbuf_i[ct1];
452         if (!PetscBTLookupSet(xtable,row)) {
453           if (!(ct3 < mem_estimate)) {
454             new_estimate = (PetscInt)(1.5*mem_estimate)+1;
455             ierr         = PetscMalloc1(new_estimate,&tmp);CHKERRQ(ierr);
456             ierr         = PetscMemcpy(tmp,xdata[0],mem_estimate*sizeof(PetscInt));CHKERRQ(ierr);
457             ierr         = PetscFree(xdata[0]);CHKERRQ(ierr);
458             xdata[0]     = tmp;
459             mem_estimate = new_estimate; ++no_malloc;
460             for (ctr=1; ctr<=i; ctr++) xdata[ctr] = xdata[ctr-1] + isz1[ctr-1];
461           }
462           xdata[i][ct2++] = row;
463           ct3++;
464         }
465       }
466       for (k=oct2,max2=ct2; k<max2; k++)  {
467         row   = xdata[i][k] - rstart;
468         start = ai[row];
469         end   = ai[row+1];
470         for (l=start; l<end; l++) {
471           val = aj[l] + cstart;
472           if (!PetscBTLookupSet(xtable,val)) {
473             if (!(ct3 < mem_estimate)) {
474               new_estimate = (PetscInt)(1.5*mem_estimate)+1;
475               ierr         = PetscMalloc1(new_estimate,&tmp);CHKERRQ(ierr);
476               ierr         = PetscMemcpy(tmp,xdata[0],mem_estimate*sizeof(PetscInt));CHKERRQ(ierr);
477               ierr         = PetscFree(xdata[0]);CHKERRQ(ierr);
478               xdata[0]     = tmp;
479               mem_estimate = new_estimate; ++no_malloc;
480               for (ctr=1; ctr<=i; ctr++) xdata[ctr] = xdata[ctr-1] + isz1[ctr-1];
481             }
482             xdata[i][ct2++] = val;
483             ct3++;
484           }
485         }
486         start = bi[row];
487         end   = bi[row+1];
488         for (l=start; l<end; l++) {
489           val = garray[bj[l]];
490           if (!PetscBTLookupSet(xtable,val)) {
491             if (!(ct3 < mem_estimate)) {
492               new_estimate = (PetscInt)(1.5*mem_estimate)+1;
493               ierr         = PetscMalloc1(new_estimate,&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       }
505       /* Update the header*/
506       xdata[i][2*j]   = ct2 - oct2; /* Undo the vector isz1 and use only a var*/
507       xdata[i][2*j-1] = rbuf_i[2*j-1];
508     }
509     xdata[i][0] = rbuf_0;
510     xdata[i+1]  = xdata[i] + ct2;
511     isz1[i]     = ct2; /* size of each message */
512   }
513   ierr = PetscBTDestroy(&xtable);CHKERRQ(ierr);
514   ierr = PetscInfo3(C,"Allocated %D bytes, required %D, no of mallocs = %D\n",mem_estimate,ct3,no_malloc);CHKERRQ(ierr);
515   PetscFunctionReturn(0);
516 }
517 
518 PetscErrorCode MatGetSubMatrices_MPIBAIJ(Mat C,PetscInt ismax,const IS isrow[],const IS iscol[],MatReuse scall,Mat *submat[])
519 {
520   IS             *isrow_block,*iscol_block;
521   Mat_MPIBAIJ    *c = (Mat_MPIBAIJ*)C->data;
522   PetscErrorCode ierr;
523   PetscInt       nmax,nstages_local,nstages,i,pos,max_no,ncol,nrow,N=C->cmap->N,bs=C->rmap->bs;
524   PetscBool      colflag,*allcolumns,*allrows;
525 
526   PetscFunctionBegin;
527   //printf("MatGetSubMatrices_MPIBAIJ scall %d, bs %d\n",scall,bs);
528   /* The compression and expansion should be avoided. Doesn't point
529      out errors, might change the indices, hence buggey */
530   ierr = PetscMalloc2(ismax+1,&isrow_block,ismax+1,&iscol_block);CHKERRQ(ierr);
531   ierr = ISCompressIndicesGeneral(N,C->rmap->n,bs,ismax,isrow,isrow_block);CHKERRQ(ierr);
532   ierr = ISCompressIndicesGeneral(N,C->cmap->n,bs,ismax,iscol,iscol_block);CHKERRQ(ierr);
533 
534   /* Check for special case: each processor gets entire matrix columns */
535   ierr = PetscMalloc2(ismax+1,&allcolumns,ismax+1,&allrows);CHKERRQ(ierr);
536   for (i=0; i<ismax; i++) {
537     ierr = ISIdentity(iscol[i],&colflag);CHKERRQ(ierr);
538     ierr = ISGetLocalSize(iscol[i],&ncol);CHKERRQ(ierr);
539     if (colflag && ncol == C->cmap->N) allcolumns[i] = PETSC_TRUE;
540     else allcolumns[i] = PETSC_FALSE;
541 
542     ierr = ISIdentity(isrow[i],&colflag);CHKERRQ(ierr);
543     ierr = ISGetLocalSize(isrow[i],&nrow);CHKERRQ(ierr);
544     if (colflag && nrow == C->rmap->N) allrows[i] = PETSC_TRUE;
545     else allrows[i] = PETSC_FALSE;
546   }
547 
548   /* Allocate memory to hold all the submatrices */
549   if (scall == MAT_INITIAL_MATRIX) {
550     ierr = PetscMalloc1(ismax+1,submat);CHKERRQ(ierr);
551   }
552   /* Determine the number of stages through which submatrices are done */
553   nmax = 20*1000000 / (c->Nbs * sizeof(PetscInt));
554   if (!nmax) nmax = 1;
555   nstages_local = ismax/nmax + ((ismax % nmax) ? 1 : 0);
556 
557   /* Make sure every processor loops through the nstages */
558   ierr = MPIU_Allreduce(&nstages_local,&nstages,1,MPIU_INT,MPI_MAX,PetscObjectComm((PetscObject)C));CHKERRQ(ierr);
559   for (i=0,pos=0; i<nstages; i++) {
560     if (pos+nmax <= ismax) max_no = nmax;
561     else if (pos == ismax) max_no = 0;
562     else                   max_no = ismax-pos;
563     ierr = MatGetSubMatrices_MPIBAIJ_local_new(C,max_no,isrow_block+pos,iscol_block+pos,scall,allrows+pos,allcolumns+pos,*submat+pos);CHKERRQ(ierr);
564     pos += max_no;
565   }
566 
567   for (i=0; i<ismax; i++) {
568     ierr = ISDestroy(&isrow_block[i]);CHKERRQ(ierr);
569     ierr = ISDestroy(&iscol_block[i]);CHKERRQ(ierr);
570   }
571   ierr = PetscFree2(isrow_block,iscol_block);CHKERRQ(ierr);
572   ierr = PetscFree2(allcolumns,allrows);CHKERRQ(ierr);
573   PetscFunctionReturn(0);
574 }
575 
576 #if defined(PETSC_USE_CTABLE)
577 PetscErrorCode PetscGetProc(const PetscInt row, const PetscMPIInt size, const PetscInt proc_gnode[], PetscMPIInt *rank)
578 {
579   PetscInt       nGlobalNd = proc_gnode[size];
580   PetscMPIInt    fproc;
581   PetscErrorCode ierr;
582 
583   PetscFunctionBegin;
584   ierr = PetscMPIIntCast((PetscInt)(((float)row * (float)size / (float)nGlobalNd + 0.5)),&fproc);CHKERRQ(ierr);
585   if (fproc > size) fproc = size;
586   while (row < proc_gnode[fproc] || row >= proc_gnode[fproc+1]) {
587     if (row < proc_gnode[fproc]) fproc--;
588     else                         fproc++;
589   }
590   *rank = fproc;
591   PetscFunctionReturn(0);
592 }
593 #endif
594 
595 /* -------------------------------------------------------------------------*/
596 /* This code is used for BAIJ and SBAIJ matrices (unfortunate dependency) */
597 
598 PetscErrorCode MatDestroy_MPIBAIJ_MatGetSubmatrices(Mat C)
599 {
600   PetscErrorCode ierr;
601   Mat_SeqBAIJ    *c = (Mat_SeqBAIJ*)C->data;
602   Mat_SubMat     *submatj = c->submatis1;
603   PetscInt       i;
604 
605   PetscFunctionBegin;
606   if (!submatj->id) { /* delete data that are linked only to submats[id=0] */
607     ierr = PetscFree4(submatj->sbuf1,submatj->ptr,submatj->tmp,submatj->ctr);CHKERRQ(ierr);
608 
609     for (i=0; i<submatj->nrqr; ++i) {
610       ierr = PetscFree(submatj->sbuf2[i]);CHKERRQ(ierr);
611     }
612     ierr = PetscFree3(submatj->sbuf2,submatj->req_size,submatj->req_source1);CHKERRQ(ierr);
613 
614     if (submatj->rbuf1) {
615       ierr = PetscFree(submatj->rbuf1[0]);CHKERRQ(ierr);
616       ierr = PetscFree(submatj->rbuf1);CHKERRQ(ierr);
617     }
618 
619     for (i=0; i<submatj->nrqs; ++i) {
620       ierr = PetscFree(submatj->rbuf3[i]);CHKERRQ(ierr);
621     }
622     ierr = PetscFree3(submatj->req_source2,submatj->rbuf2,submatj->rbuf3);CHKERRQ(ierr);
623     ierr = PetscFree(submatj->pa);CHKERRQ(ierr);
624   }
625 
626 #if defined(PETSC_USE_CTABLE)
627   ierr = PetscTableDestroy((PetscTable*)&submatj->rmap);CHKERRQ(ierr);
628   if (submatj->cmap_loc) {ierr = PetscFree(submatj->cmap_loc);CHKERRQ(ierr);}
629   ierr = PetscFree(submatj->rmap_loc);CHKERRQ(ierr);
630 #else
631   ierr = PetscFree(submatj->rmap);CHKERRQ(ierr);
632 #endif
633 
634   if (!submatj->allcolumns) {
635 #if defined(PETSC_USE_CTABLE)
636     ierr = PetscTableDestroy((PetscTable*)&submatj->cmap);CHKERRQ(ierr);
637 #else
638     ierr = PetscFree(submatj->cmap);CHKERRQ(ierr);
639 #endif
640   }
641   ierr = submatj->destroy(C);CHKERRQ(ierr);
642   ierr = PetscFree(submatj->row2proc);CHKERRQ(ierr);
643 
644   ierr = PetscFree(submatj);CHKERRQ(ierr);
645   PetscFunctionReturn(0);
646 }
647 
648 #if 1
649 PetscErrorCode MatGetSubMatrices_MPIBAIJ_local_new(Mat C,PetscInt ismax,const IS isrow[],const IS iscol[],MatReuse scall,PetscBool *allrows,PetscBool *allcolumns,Mat *submats)
650 {
651   Mat_MPIBAIJ     *c = (Mat_MPIBAIJ*)C->data;
652   Mat            A  = c->A;
653   Mat_SeqBAIJ     *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ*)c->B->data,*subc;
654   const PetscInt **icol,**irow;
655   PetscInt       *nrow,*ncol,start;
656   PetscErrorCode ierr;
657   PetscMPIInt    rank,size,tag0,tag2,tag3,tag4,*w1,*w2,*w3,*w4,nrqr;
658   PetscInt       **sbuf1,**sbuf2,i,j,k,l,ct1,ct2,**rbuf1,row,proc=-1;
659   PetscInt       nrqs=0,msz,**ptr=NULL,*req_size=NULL,*ctr=NULL,*pa,*tmp=NULL,tcol;
660   PetscInt       **rbuf3=NULL,*req_source1=NULL,*req_source2,**sbuf_aj,**rbuf2=NULL,max1,max2;
661   PetscInt       **lens,is_no,ncols,*cols,mat_i,*mat_j,tmp2,jmax;
662 #if defined(PETSC_USE_CTABLE)
663   PetscTable     *cmap,cmap_i=NULL,*rmap,rmap_i;
664 #else
665   PetscInt       **cmap,*cmap_i=NULL,**rmap,*rmap_i;
666 #endif
667   const PetscInt *irow_i;
668   PetscInt       ctr_j,*sbuf1_j,*sbuf_aj_i,*rbuf1_i,kmax,*lens_i;
669   MPI_Request    *s_waits1,*r_waits1,*s_waits2,*r_waits2,*r_waits3;
670   MPI_Request    *r_waits4,*s_waits3,*s_waits4;
671   MPI_Status     *r_status1,*r_status2,*s_status1,*s_status3,*s_status2;
672   MPI_Status     *r_status3,*r_status4,*s_status4;
673   MPI_Comm       comm;
674   PetscScalar    **rbuf4,*rbuf4_i,**sbuf_aa,*vals,*mat_a,*imat_a,*sbuf_aa_i;
675   PetscMPIInt    *onodes1,*olengths1,end;
676   PetscInt       **row2proc,*row2proc_i,ilen_row,*imat_ilen,*imat_j,*imat_i,old_row;
677   Mat_SubMat     **smats,*smat_i;
678   PetscBool      *issorted,colflag,iscsorted=PETSC_TRUE;
679   PetscInt       *sbuf1_i,*rbuf2_i,*rbuf3_i,ilen;
680 
681   PetscFunctionBegin;
682   ierr = PetscObjectGetComm((PetscObject)C,&comm);CHKERRQ(ierr);
683   size = c->size;
684   rank = c->rank;
685   if (!rank) printf("MatGetSubMatrices_MPIBAIJ_new scall %d\n",scall);
686 
687   ierr = PetscMalloc5(ismax,&smats,ismax,&row2proc,ismax,&cmap,ismax,&rmap,ismax,&allcolumns);CHKERRQ(ierr);
688   ierr = PetscMalloc5(ismax,&irow,ismax,&icol,ismax,&nrow,ismax,&ncol,ismax,&issorted);CHKERRQ(ierr);
689 
690   for (i=0; i<ismax; i++) {
691     ierr = ISSorted(iscol[i],&issorted[i]);CHKERRQ(ierr);
692     if (!issorted[i]) iscsorted = issorted[i];
693 
694     ierr = ISSorted(isrow[i],&issorted[i]);CHKERRQ(ierr);
695 
696     ierr = ISGetIndices(isrow[i],&irow[i]);CHKERRQ(ierr);
697     ierr = ISGetLocalSize(isrow[i],&nrow[i]);CHKERRQ(ierr);
698 
699     /* Check for special case: allcolumn */
700     ierr = ISIdentity(iscol[i],&colflag);CHKERRQ(ierr);
701     ierr = ISGetLocalSize(iscol[i],&ncol[i]);CHKERRQ(ierr);
702     if (colflag && ncol[i] == C->cmap->N) {
703       allcolumns[i] = PETSC_TRUE;
704       icol[i] = NULL;
705     } else {
706       allcolumns[i] = PETSC_FALSE;
707       ierr = ISGetIndices(iscol[i],&icol[i]);CHKERRQ(ierr);
708     }
709   }
710 
711   if (scall == MAT_REUSE_MATRIX) {
712     /* Assumes new rows are same length as the old rows */
713     for (i=0; i<ismax; i++) {
714       subc = (Mat_SeqBAIJ*)(submats[i]->data);
715       if ((submats[i]->rmap->n != nrow[i]) || (submats[i]->cmap->n != ncol[i])) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Cannot reuse matrix. wrong size");
716 
717       /* Initial matrix as if empty */
718       ierr = PetscMemzero(subc->ilen,submats[i]->rmap->n*sizeof(PetscInt));CHKERRQ(ierr);
719 
720       /* Initial matrix as if empty */
721       submats[i]->factortype = C->factortype;
722 
723       smat_i   = subc->submatis1;
724       smats[i] = smat_i;
725 
726       nrqs        = smat_i->nrqs;
727       nrqr        = smat_i->nrqr;
728       rbuf1       = smat_i->rbuf1;
729       rbuf2       = smat_i->rbuf2;
730       rbuf3       = smat_i->rbuf3;
731       req_source2 = smat_i->req_source2;
732 
733       sbuf1     = smat_i->sbuf1;
734       sbuf2     = smat_i->sbuf2;
735       ptr       = smat_i->ptr;
736       tmp       = smat_i->tmp;
737       ctr       = smat_i->ctr;
738 
739       pa          = smat_i->pa;
740       req_size    = smat_i->req_size;
741       req_source1 = smat_i->req_source1;
742 
743       allcolumns[i] = smat_i->allcolumns;
744       row2proc[i]   = smat_i->row2proc;
745       rmap[i]       = smat_i->rmap;
746       cmap[i]       = smat_i->cmap;
747     }
748   } else { /* scall == MAT_INITIAL_MATRIX */
749     /* Get some new tags to keep the communication clean */
750     ierr = PetscObjectGetNewTag((PetscObject)C,&tag2);CHKERRQ(ierr);
751     ierr = PetscObjectGetNewTag((PetscObject)C,&tag3);CHKERRQ(ierr);
752 
753     /* evaluate communication - mesg to who, length of mesg, and buffer space
754      required. Based on this, buffers are allocated, and data copied into them*/
755     ierr = PetscCalloc4(size,&w1,size,&w2,size,&w3,size,&w4);CHKERRQ(ierr);   /* mesg size, initialize work vectors */
756 
757     for (i=0; i<ismax; i++) {
758       jmax   = nrow[i];
759       irow_i = irow[i];
760 
761       ierr   = PetscMalloc1(jmax,&row2proc_i);CHKERRQ(ierr);
762       row2proc[i] = row2proc_i;
763 
764       if (issorted[i]) proc = 0;
765       for (j=0; j<jmax; j++) {
766         if (!issorted[i]) proc = 0;
767         row = irow_i[j];
768         while (row >= C->rmap->range[proc+1]) proc++;
769         w4[proc]++;
770         row2proc_i[j] = proc; /* map row index to proc */
771       }
772       for (j=0; j<size; j++) {
773         if (w4[j]) { w1[j] += w4[j];  w3[j]++; w4[j] = 0;}
774       }
775     }
776 
777     nrqs     = 0;              /* no of outgoing messages */
778     msz      = 0;              /* total mesg length (for all procs) */
779     w1[rank] = 0;              /* no mesg sent to self */
780     w3[rank] = 0;
781     for (i=0; i<size; i++) {
782       if (w1[i])  { w2[i] = 1; nrqs++;} /* there exists a message to proc i */
783     }
784     ierr = PetscMalloc1(nrqs+1,&pa);CHKERRQ(ierr); /*(proc -array)*/
785     for (i=0,j=0; i<size; i++) {
786       if (w1[i]) { pa[j] = i; j++; }
787     }
788 
789     /* Each message would have a header = 1 + 2*(no of IS) + data */
790     for (i=0; i<nrqs; i++) {
791       j      = pa[i];
792       w1[j] += w2[j] + 2* w3[j];
793       msz   += w1[j];
794     }
795     ierr = PetscInfo2(0,"Number of outgoing messages %D Total message length %D\n",nrqs,msz);CHKERRQ(ierr);
796 
797     /* Determine the number of messages to expect, their lengths, from from-ids */
798     ierr = PetscGatherNumberOfMessages(comm,w2,w1,&nrqr);CHKERRQ(ierr);
799     ierr = PetscGatherMessageLengths(comm,nrqs,nrqr,w1,&onodes1,&olengths1);CHKERRQ(ierr);
800 
801     /* Now post the Irecvs corresponding to these messages */
802     tag0 = ((PetscObject)C)->tag;
803     ierr = PetscPostIrecvInt(comm,tag0,nrqr,onodes1,olengths1,&rbuf1,&r_waits1);CHKERRQ(ierr);
804 
805     ierr = PetscFree(onodes1);CHKERRQ(ierr);
806     ierr = PetscFree(olengths1);CHKERRQ(ierr);
807 
808     /* Allocate Memory for outgoing messages */
809     ierr = PetscMalloc4(size,&sbuf1,size,&ptr,2*msz,&tmp,size,&ctr);CHKERRQ(ierr);
810     ierr = PetscMemzero(sbuf1,size*sizeof(PetscInt*));CHKERRQ(ierr);
811     ierr = PetscMemzero(ptr,size*sizeof(PetscInt*));CHKERRQ(ierr);
812 
813     {
814       PetscInt *iptr = tmp;
815       k    = 0;
816       for (i=0; i<nrqs; i++) {
817         j        = pa[i];
818         iptr    += k;
819         sbuf1[j] = iptr;
820         k        = w1[j];
821       }
822     }
823 
824     /* Form the outgoing messages. Initialize the header space */
825     for (i=0; i<nrqs; i++) {
826       j           = pa[i];
827       sbuf1[j][0] = 0;
828       ierr        = PetscMemzero(sbuf1[j]+1,2*w3[j]*sizeof(PetscInt));CHKERRQ(ierr);
829       ptr[j]      = sbuf1[j] + 2*w3[j] + 1;
830     }
831 
832     /* Parse the isrow and copy data into outbuf */
833     for (i=0; i<ismax; i++) {
834       row2proc_i = row2proc[i];
835       ierr   = PetscMemzero(ctr,size*sizeof(PetscInt));CHKERRQ(ierr);
836       irow_i = irow[i];
837       jmax   = nrow[i];
838       for (j=0; j<jmax; j++) {  /* parse the indices of each IS */
839         proc = row2proc_i[j];
840         if (proc != rank) { /* copy to the outgoing buf*/
841           ctr[proc]++;
842           *ptr[proc] = irow_i[j];
843           ptr[proc]++;
844         }
845       }
846       /* Update the headers for the current IS */
847       for (j=0; j<size; j++) { /* Can Optimise this loop too */
848         if ((ctr_j = ctr[j])) {
849           sbuf1_j        = sbuf1[j];
850           k              = ++sbuf1_j[0];
851           sbuf1_j[2*k]   = ctr_j;
852           sbuf1_j[2*k-1] = i;
853         }
854       }
855     }
856 
857     /*  Now  post the sends */
858     ierr = PetscMalloc1(nrqs+1,&s_waits1);CHKERRQ(ierr);
859     for (i=0; i<nrqs; ++i) {
860       j    = pa[i];
861       ierr = MPI_Isend(sbuf1[j],w1[j],MPIU_INT,j,tag0,comm,s_waits1+i);CHKERRQ(ierr);
862     }
863 
864     /* Post Receives to capture the buffer size */
865     ierr = PetscMalloc1(nrqs+1,&r_waits2);CHKERRQ(ierr);
866     ierr = PetscMalloc3(nrqs+1,&req_source2,nrqs+1,&rbuf2,nrqs+1,&rbuf3);CHKERRQ(ierr);
867     rbuf2[0] = tmp + msz;
868     for (i=1; i<nrqs; ++i) {
869       rbuf2[i] = rbuf2[i-1]+w1[pa[i-1]];
870     }
871     for (i=0; i<nrqs; ++i) {
872       j    = pa[i];
873       ierr = MPI_Irecv(rbuf2[i],w1[j],MPIU_INT,j,tag2,comm,r_waits2+i);CHKERRQ(ierr);
874     }
875 
876     /* Send to other procs the buf size they should allocate */
877     /* Receive messages*/
878     ierr = PetscMalloc1(nrqr+1,&s_waits2);CHKERRQ(ierr);
879     ierr = PetscMalloc1(nrqr+1,&r_status1);CHKERRQ(ierr);
880     ierr = PetscMalloc3(nrqr,&sbuf2,nrqr,&req_size,nrqr,&req_source1);CHKERRQ(ierr);
881     {
882       PetscInt   *sAi = a->i,*sBi = b->i,id,rstart = C->rmap->rstart;
883       PetscInt   *sbuf2_i;
884 
885       ierr = MPI_Waitall(nrqr,r_waits1,r_status1);CHKERRQ(ierr);
886       for (i=0; i<nrqr; ++i) {
887         req_size[i] = 0;
888         rbuf1_i        = rbuf1[i];
889         start          = 2*rbuf1_i[0] + 1;
890         ierr           = MPI_Get_count(r_status1+i,MPIU_INT,&end);CHKERRQ(ierr);
891         ierr           = PetscMalloc1(end+1,&sbuf2[i]);CHKERRQ(ierr);
892         sbuf2_i        = sbuf2[i];
893         for (j=start; j<end; j++) {
894           id              = rbuf1_i[j] - rstart;
895           ncols           = sAi[id+1] - sAi[id] + sBi[id+1] - sBi[id];
896           sbuf2_i[j]      = ncols;
897           req_size[i] += ncols;
898         }
899         req_source1[i] = r_status1[i].MPI_SOURCE;
900         /* form the header */
901         sbuf2_i[0] = req_size[i];
902         for (j=1; j<start; j++) sbuf2_i[j] = rbuf1_i[j];
903 
904         ierr = MPI_Isend(sbuf2_i,end,MPIU_INT,req_source1[i],tag2,comm,s_waits2+i);CHKERRQ(ierr);
905       }
906     }
907     ierr = PetscFree(r_status1);CHKERRQ(ierr);
908     ierr = PetscFree(r_waits1);CHKERRQ(ierr);
909     ierr = PetscFree4(w1,w2,w3,w4);CHKERRQ(ierr);
910 
911     /* Receive messages*/
912     ierr = PetscMalloc1(nrqs+1,&r_waits3);CHKERRQ(ierr);
913     ierr = PetscMalloc1(nrqs+1,&r_status2);CHKERRQ(ierr);
914 
915     ierr = MPI_Waitall(nrqs,r_waits2,r_status2);CHKERRQ(ierr);
916     for (i=0; i<nrqs; ++i) {
917       ierr = PetscMalloc1(rbuf2[i][0]+1,&rbuf3[i]);CHKERRQ(ierr);
918       req_source2[i] = r_status2[i].MPI_SOURCE;
919       ierr = MPI_Irecv(rbuf3[i],rbuf2[i][0],MPIU_INT,req_source2[i],tag3,comm,r_waits3+i);CHKERRQ(ierr);
920     }
921     ierr = PetscFree(r_status2);CHKERRQ(ierr);
922     ierr = PetscFree(r_waits2);CHKERRQ(ierr);
923 
924     /* Wait on sends1 and sends2 */
925     ierr = PetscMalloc1(nrqs+1,&s_status1);CHKERRQ(ierr);
926     ierr = PetscMalloc1(nrqr+1,&s_status2);CHKERRQ(ierr);
927 
928     if (nrqs) {ierr = MPI_Waitall(nrqs,s_waits1,s_status1);CHKERRQ(ierr);}
929     if (nrqr) {ierr = MPI_Waitall(nrqr,s_waits2,s_status2);CHKERRQ(ierr);}
930     ierr = PetscFree(s_status1);CHKERRQ(ierr);
931     ierr = PetscFree(s_status2);CHKERRQ(ierr);
932     ierr = PetscFree(s_waits1);CHKERRQ(ierr);
933     ierr = PetscFree(s_waits2);CHKERRQ(ierr);
934 
935     /* Now allocate sending buffers for a->j, and send them off */
936     ierr = PetscMalloc1(nrqr+1,&sbuf_aj);CHKERRQ(ierr);
937     for (i=0,j=0; i<nrqr; i++) j += req_size[i];
938     ierr = PetscMalloc1(j+1,&sbuf_aj[0]);CHKERRQ(ierr);
939     for (i=1; i<nrqr; i++) sbuf_aj[i] = sbuf_aj[i-1] + req_size[i-1];
940 
941     ierr = PetscMalloc1(nrqr+1,&s_waits3);CHKERRQ(ierr);
942     {
943       PetscInt nzA,nzB,*a_i = a->i,*b_i = b->i,lwrite;
944       PetscInt *cworkA,*cworkB,cstart = C->cmap->rstart,rstart = C->rmap->rstart,*bmap = c->garray;
945       PetscInt cend = C->cmap->rend;
946       PetscInt *a_j = a->j,*b_j = b->j,ctmp;
947 
948       for (i=0; i<nrqr; i++) {
949         rbuf1_i   = rbuf1[i];
950         sbuf_aj_i = sbuf_aj[i];
951         ct1       = 2*rbuf1_i[0] + 1;
952         ct2       = 0;
953         for (j=1,max1=rbuf1_i[0]; j<=max1; j++) {
954           kmax = rbuf1[i][2*j];
955           for (k=0; k<kmax; k++,ct1++) {
956             row    = rbuf1_i[ct1] - rstart;
957             nzA    = a_i[row+1] - a_i[row]; nzB = b_i[row+1] - b_i[row];
958             ncols  = nzA + nzB;
959             cworkA = a_j + a_i[row]; cworkB = b_j + b_i[row];
960 
961             /* load the column indices for this row into cols */
962             cols = sbuf_aj_i + ct2;
963 
964             lwrite = 0;
965             for (l=0; l<nzB; l++) {
966               if ((ctmp = bmap[cworkB[l]]) < cstart) cols[lwrite++] = ctmp;
967             }
968             for (l=0; l<nzA; l++) cols[lwrite++] = cstart + cworkA[l];
969             for (l=0; l<nzB; l++) {
970               if ((ctmp = bmap[cworkB[l]]) >= cend) cols[lwrite++] = ctmp;
971             }
972 
973             ct2 += ncols;
974           }
975         }
976         ierr = MPI_Isend(sbuf_aj_i,req_size[i],MPIU_INT,req_source1[i],tag3,comm,s_waits3+i);CHKERRQ(ierr);
977       }
978     }
979     ierr = PetscMalloc2(nrqs+1,&r_status3,nrqr+1,&s_status3);CHKERRQ(ierr);
980 
981     /* create col map: global col of C -> local col of submatrices */
982     {
983       const PetscInt *icol_i;
984 #if defined(PETSC_USE_CTABLE)
985       for (i=0; i<ismax; i++) {
986         if (!allcolumns[i]) {
987           ierr = PetscTableCreate(ncol[i]+1,C->cmap->N+1,&cmap[i]);CHKERRQ(ierr);
988 
989           jmax   = ncol[i];
990           icol_i = icol[i];
991           cmap_i = cmap[i];
992           for (j=0; j<jmax; j++) {
993             ierr = PetscTableAdd(cmap[i],icol_i[j]+1,j+1,INSERT_VALUES);CHKERRQ(ierr);
994           }
995         } else cmap[i] = NULL;
996       }
997 #else
998       for (i=0; i<ismax; i++) {
999         if (!allcolumns[i]) {
1000           ierr   = PetscCalloc1(C->cmap->N,&cmap[i]);CHKERRQ(ierr);
1001           jmax   = ncol[i];
1002           icol_i = icol[i];
1003           cmap_i = cmap[i];
1004           for (j=0; j<jmax; j++) {
1005             cmap_i[icol_i[j]] = j+1;
1006           }
1007         } else cmap[i] = NULL;
1008       }
1009 #endif
1010     }
1011 
1012     /* Create lens which is required for MatCreate... */
1013     for (i=0,j=0; i<ismax; i++) j += nrow[i];
1014     ierr = PetscMalloc1(ismax,&lens);CHKERRQ(ierr);
1015 
1016     if (ismax) {
1017       ierr = PetscCalloc1(j,&lens[0]);CHKERRQ(ierr);
1018     }
1019     for (i=1; i<ismax; i++) lens[i] = lens[i-1] + nrow[i-1];
1020 
1021     /* Update lens from local data */
1022     for (i=0; i<ismax; i++) {
1023       row2proc_i = row2proc[i];
1024       jmax = nrow[i];
1025       if (!allcolumns[i]) cmap_i = cmap[i];
1026       irow_i = irow[i];
1027       lens_i = lens[i];
1028       for (j=0; j<jmax; j++) {
1029         row = irow_i[j];
1030         proc = row2proc_i[j];
1031         if (proc == rank) {
1032           ierr = MatGetRow_MPIBAIJ(C,row,&ncols,&cols,0);CHKERRQ(ierr);
1033           if (!allcolumns[i]) {
1034             for (k=0; k<ncols; k++) {
1035 #if defined(PETSC_USE_CTABLE)
1036               ierr = PetscTableFind(cmap_i,cols[k]+1,&tcol);CHKERRQ(ierr);
1037 #else
1038               tcol = cmap_i[cols[k]];
1039 #endif
1040               if (tcol) lens_i[j]++;
1041             }
1042           } else { /* allcolumns */
1043             lens_i[j] = ncols;
1044           }
1045           ierr = MatRestoreRow_MPIBAIJ(C,row,&ncols,&cols,0);CHKERRQ(ierr);
1046         }
1047       }
1048     }
1049 
1050     /* Create row map: global row of C -> local row of submatrices */
1051 #if defined(PETSC_USE_CTABLE)
1052     for (i=0; i<ismax; i++) {
1053       ierr   = PetscTableCreate(nrow[i]+1,C->rmap->N+1,&rmap[i]);CHKERRQ(ierr);
1054       irow_i = irow[i];
1055       jmax   = nrow[i];
1056       for (j=0; j<jmax; j++) {
1057       ierr = PetscTableAdd(rmap[i],irow_i[j]+1,j+1,INSERT_VALUES);CHKERRQ(ierr);
1058       }
1059     }
1060 #else
1061     for (i=0; i<ismax; i++) {
1062       ierr   = PetscCalloc1(C->rmap->N,&rmap[i]);CHKERRQ(ierr);
1063       rmap_i = rmap[i];
1064       irow_i = irow[i];
1065       jmax   = nrow[i];
1066       for (j=0; j<jmax; j++) {
1067         rmap_i[irow_i[j]] = j;
1068       }
1069     }
1070 #endif
1071 
1072     /* Update lens from offproc data */
1073     {
1074       PetscInt *rbuf2_i,*rbuf3_i,*sbuf1_i;
1075 
1076       ierr    = MPI_Waitall(nrqs,r_waits3,r_status3);CHKERRQ(ierr);
1077       for (tmp2=0; tmp2<nrqs; tmp2++) {
1078         sbuf1_i = sbuf1[pa[tmp2]];
1079         jmax    = sbuf1_i[0];
1080         ct1     = 2*jmax+1;
1081         ct2     = 0;
1082         rbuf2_i = rbuf2[tmp2];
1083         rbuf3_i = rbuf3[tmp2];
1084         for (j=1; j<=jmax; j++) {
1085           is_no  = sbuf1_i[2*j-1];
1086           max1   = sbuf1_i[2*j];
1087           lens_i = lens[is_no];
1088           if (!allcolumns[is_no]) cmap_i = cmap[is_no];
1089           rmap_i = rmap[is_no];
1090           for (k=0; k<max1; k++,ct1++) {
1091 #if defined(PETSC_USE_CTABLE)
1092             ierr = PetscTableFind(rmap_i,sbuf1_i[ct1]+1,&row);CHKERRQ(ierr);
1093             row--;
1094             if (row < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"row not found in table");
1095 #else
1096             row = rmap_i[sbuf1_i[ct1]]; /* the val in the new matrix to be */
1097 #endif
1098             max2 = rbuf2_i[ct1];
1099             for (l=0; l<max2; l++,ct2++) {
1100               if (!allcolumns[is_no]) {
1101 #if defined(PETSC_USE_CTABLE)
1102                 ierr = PetscTableFind(cmap_i,rbuf3_i[ct2]+1,&tcol);CHKERRQ(ierr);
1103 #else
1104                 tcol = cmap_i[rbuf3_i[ct2]];
1105 #endif
1106                 if (tcol) lens_i[row]++;
1107               } else { /* allcolumns */
1108                 lens_i[row]++; /* lens_i[row] += max2 ? */
1109               }
1110             }
1111           }
1112         }
1113       }
1114     }
1115     ierr = PetscFree(r_waits3);CHKERRQ(ierr);
1116     if (nrqr) {ierr = MPI_Waitall(nrqr,s_waits3,s_status3);CHKERRQ(ierr);}
1117     ierr = PetscFree2(r_status3,s_status3);CHKERRQ(ierr);
1118     ierr = PetscFree(s_waits3);CHKERRQ(ierr);
1119 
1120     /* Create the submatrices */
1121     for (i=0; i<ismax; i++) {
1122       PetscInt    rbs,cbs;
1123 
1124       ierr = ISGetBlockSize(isrow[i],&rbs);CHKERRQ(ierr);
1125       ierr = ISGetBlockSize(iscol[i],&cbs);CHKERRQ(ierr);
1126 
1127       ierr = MatCreate(PETSC_COMM_SELF,submats+i);CHKERRQ(ierr);
1128       ierr = MatSetSizes(submats[i],nrow[i],ncol[i],PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
1129 
1130       ierr = MatSetBlockSizes(submats[i],rbs,cbs);CHKERRQ(ierr);
1131       ierr = MatSetType(submats[i],((PetscObject)A)->type_name);CHKERRQ(ierr);
1132       ierr = MatSeqBAIJSetPreallocation(submats[i],1,0,lens[i]);CHKERRQ(ierr); //bs=1!
1133       ierr = MatSeqSBAIJSetPreallocation(submats[i],1,0,lens[i]);CHKERRQ(ierr); /* this subroutine is used by SBAIJ routines */
1134 
1135       /* create struct Mat_SubMat and attached it to submat */
1136       ierr = PetscNew(&smat_i);CHKERRQ(ierr);
1137       subc = (Mat_SeqBAIJ*)submats[i]->data;
1138       subc->submatis1 = smat_i;
1139       smats[i]        = smat_i;
1140 
1141       smat_i->destroy          = submats[i]->ops->destroy;
1142       submats[i]->ops->destroy = MatDestroy_MPIBAIJ_MatGetSubmatrices;
1143       submats[i]->factortype   = C->factortype;
1144 
1145       smat_i->id          = i;
1146       smat_i->nrqs        = nrqs;
1147       smat_i->nrqr        = nrqr;
1148       smat_i->rbuf1       = rbuf1;
1149       smat_i->rbuf2       = rbuf2;
1150       smat_i->rbuf3       = rbuf3;
1151       smat_i->sbuf2       = sbuf2;
1152       smat_i->req_source2 = req_source2;
1153 
1154       smat_i->sbuf1       = sbuf1;
1155       smat_i->ptr         = ptr;
1156       smat_i->tmp         = tmp;
1157       smat_i->ctr         = ctr;
1158 
1159       smat_i->pa           = pa;
1160       smat_i->req_size     = req_size;
1161       smat_i->req_source1  = req_source1;
1162 
1163       smat_i->allcolumns  = allcolumns[i];
1164       smat_i->singleis    = PETSC_FALSE;
1165       smat_i->row2proc    = row2proc[i];
1166       smat_i->rmap        = rmap[i];
1167       smat_i->cmap        = cmap[i];
1168     }
1169 
1170     if (ismax) {ierr = PetscFree(lens[0]);CHKERRQ(ierr);}
1171     ierr = PetscFree(lens);CHKERRQ(ierr);
1172     ierr = PetscFree(sbuf_aj[0]);CHKERRQ(ierr);
1173     ierr = PetscFree(sbuf_aj);CHKERRQ(ierr);
1174 
1175   } /* endof scall == MAT_INITIAL_MATRIX */
1176 
1177   /* Post recv matrix values */
1178   ierr = PetscObjectGetNewTag((PetscObject)C,&tag4);CHKERRQ(ierr);
1179   ierr = PetscMalloc1(nrqs+1,&rbuf4);CHKERRQ(ierr);
1180   ierr = PetscMalloc1(nrqs+1,&r_waits4);CHKERRQ(ierr);
1181   ierr = PetscMalloc1(nrqs+1,&r_status4);CHKERRQ(ierr);
1182   ierr = PetscMalloc1(nrqr+1,&s_status4);CHKERRQ(ierr);
1183   for (i=0; i<nrqs; ++i) {
1184     ierr = PetscMalloc1(rbuf2[i][0]+1,&rbuf4[i]);CHKERRQ(ierr);
1185     ierr = MPI_Irecv(rbuf4[i],rbuf2[i][0],MPIU_SCALAR,req_source2[i],tag4,comm,r_waits4+i);CHKERRQ(ierr);
1186   }
1187 
1188   /* Allocate sending buffers for a->a, and send them off */
1189   ierr = PetscMalloc1(nrqr+1,&sbuf_aa);CHKERRQ(ierr);
1190   for (i=0,j=0; i<nrqr; i++) j += req_size[i];
1191   ierr = PetscMalloc1(j+1,&sbuf_aa[0]);CHKERRQ(ierr);
1192   for (i=1; i<nrqr; i++) sbuf_aa[i] = sbuf_aa[i-1] + req_size[i-1];
1193 
1194   ierr = PetscMalloc1(nrqr+1,&s_waits4);CHKERRQ(ierr);
1195   {
1196     PetscInt    nzA,nzB,*a_i = a->i,*b_i = b->i, *cworkB,lwrite;
1197     PetscInt    cstart = C->cmap->rstart,rstart = C->rmap->rstart,*bmap = c->garray;
1198     PetscInt    cend   = C->cmap->rend;
1199     PetscInt    *b_j   = b->j;
1200     PetscScalar *vworkA,*vworkB,*a_a = a->a,*b_a = b->a;
1201 
1202     for (i=0; i<nrqr; i++) {
1203       rbuf1_i   = rbuf1[i];
1204       sbuf_aa_i = sbuf_aa[i];
1205       ct1       = 2*rbuf1_i[0]+1;
1206       ct2       = 0;
1207       for (j=1,max1=rbuf1_i[0]; j<=max1; j++) {
1208         kmax = rbuf1_i[2*j];
1209         for (k=0; k<kmax; k++,ct1++) {
1210           row    = rbuf1_i[ct1] - rstart;
1211           nzA    = a_i[row+1] - a_i[row];     nzB = b_i[row+1] - b_i[row];
1212           ncols  = nzA + nzB;
1213           cworkB = b_j + b_i[row];
1214           vworkA = a_a + a_i[row];
1215           vworkB = b_a + b_i[row];
1216 
1217           /* load the column values for this row into vals*/
1218           vals = sbuf_aa_i+ct2;
1219 
1220           lwrite = 0;
1221           for (l=0; l<nzB; l++) {
1222             if ((bmap[cworkB[l]]) < cstart) vals[lwrite++] = vworkB[l];
1223           }
1224           for (l=0; l<nzA; l++) vals[lwrite++] = vworkA[l];
1225           for (l=0; l<nzB; l++) {
1226             if ((bmap[cworkB[l]]) >= cend) vals[lwrite++] = vworkB[l];
1227           }
1228 
1229           ct2 += ncols;
1230         }
1231       }
1232       ierr = MPI_Isend(sbuf_aa_i,req_size[i],MPIU_SCALAR,req_source1[i],tag4,comm,s_waits4+i);CHKERRQ(ierr);
1233     }
1234   }
1235 
1236   if (!ismax) {
1237     ierr = PetscFree(rbuf1[0]);CHKERRQ(ierr);
1238     ierr = PetscFree(rbuf1);CHKERRQ(ierr);
1239   }
1240 
1241   /* Assemble the matrices */
1242   /* First assemble the local rows */
1243   for (i=0; i<ismax; i++) {
1244     row2proc_i = row2proc[i];
1245     subc      = (Mat_SeqBAIJ*)submats[i]->data;
1246     imat_ilen = subc->ilen;
1247     imat_j    = subc->j;
1248     imat_i    = subc->i;
1249     imat_a    = subc->a;
1250 
1251     if (!allcolumns[i]) cmap_i = cmap[i];
1252     rmap_i = rmap[i];
1253     irow_i = irow[i];
1254     jmax   = nrow[i];
1255     for (j=0; j<jmax; j++) {
1256       row  = irow_i[j];
1257       proc = row2proc_i[j];
1258       if (proc == rank) {
1259         old_row = row;
1260 #if defined(PETSC_USE_CTABLE)
1261         ierr = PetscTableFind(rmap_i,row+1,&row);CHKERRQ(ierr);
1262         row--;
1263 #else
1264         row = rmap_i[row];
1265 #endif
1266         ilen_row = imat_ilen[row];
1267         ierr     = MatGetRow_MPIBAIJ(C,old_row,&ncols,&cols,&vals);CHKERRQ(ierr);
1268         mat_i    = imat_i[row];
1269         mat_a    = imat_a + mat_i;
1270         mat_j    = imat_j + mat_i;
1271         if (!allcolumns[i]) {
1272           for (k=0; k<ncols; k++) {
1273 #if defined(PETSC_USE_CTABLE)
1274             ierr = PetscTableFind(cmap_i,cols[k]+1,&tcol);CHKERRQ(ierr);
1275 #else
1276             tcol = cmap_i[cols[k]];
1277 #endif
1278             if (tcol) {
1279               *mat_j++ = tcol - 1;
1280               *mat_a++ = vals[k];
1281               ilen_row++;
1282             }
1283           }
1284         } else { /* allcolumns */
1285           for (k=0; k<ncols; k++) {
1286             *mat_j++ = cols[k];  /* global col index! */
1287             *mat_a++ = vals[k];
1288             ilen_row++;
1289           }
1290         }
1291         ierr = MatRestoreRow_MPIBAIJ(C,old_row,&ncols,&cols,&vals);CHKERRQ(ierr);
1292 
1293         imat_ilen[row] = ilen_row;
1294       }
1295     }
1296   }
1297 
1298   /* Now assemble the off proc rows */
1299   ierr    = MPI_Waitall(nrqs,r_waits4,r_status4);CHKERRQ(ierr);
1300   for (tmp2=0; tmp2<nrqs; tmp2++) {
1301     sbuf1_i = sbuf1[pa[tmp2]];
1302     jmax    = sbuf1_i[0];
1303     ct1     = 2*jmax + 1;
1304     ct2     = 0;
1305     rbuf2_i = rbuf2[tmp2];
1306     rbuf3_i = rbuf3[tmp2];
1307     rbuf4_i = rbuf4[tmp2];
1308     for (j=1; j<=jmax; j++) {
1309       is_no     = sbuf1_i[2*j-1];
1310       rmap_i    = rmap[is_no];
1311       if (!allcolumns[is_no]) cmap_i = cmap[is_no];
1312       subc      = (Mat_SeqBAIJ*)submats[is_no]->data;
1313       imat_ilen = subc->ilen;
1314       imat_j    = subc->j;
1315       imat_i    = subc->i;
1316       imat_a    = subc->a;
1317       max1      = sbuf1_i[2*j];
1318       for (k=0; k<max1; k++,ct1++) {
1319         row = sbuf1_i[ct1];
1320 #if defined(PETSC_USE_CTABLE)
1321         ierr = PetscTableFind(rmap_i,row+1,&row);CHKERRQ(ierr);
1322         row--;
1323 #else
1324         row = rmap_i[row];
1325 #endif
1326         ilen  = imat_ilen[row];
1327         mat_i = imat_i[row];
1328         mat_a = imat_a + mat_i;
1329         mat_j = imat_j + mat_i;
1330         max2  = rbuf2_i[ct1];
1331         if (!allcolumns[is_no]) {
1332           for (l=0; l<max2; l++,ct2++) {
1333 #if defined(PETSC_USE_CTABLE)
1334             ierr = PetscTableFind(cmap_i,rbuf3_i[ct2]+1,&tcol);CHKERRQ(ierr);
1335 #else
1336             tcol = cmap_i[rbuf3_i[ct2]];
1337 #endif
1338             if (tcol) {
1339               *mat_j++ = tcol - 1;
1340               *mat_a++ = rbuf4_i[ct2];
1341               ilen++;
1342             }
1343           }
1344         } else { /* allcolumns */
1345           for (l=0; l<max2; l++,ct2++) {
1346             *mat_j++ = rbuf3_i[ct2]; /* same global column index of C */
1347             *mat_a++ = rbuf4_i[ct2];
1348             ilen++;
1349           }
1350         }
1351         imat_ilen[row] = ilen;
1352       }
1353     }
1354   }
1355 
1356   if (!iscsorted) { /* sort column indices of the rows */
1357     for (i=0; i<ismax; i++) {
1358       subc       = (Mat_SeqBAIJ*)submats[i]->data;
1359       imat_j    = subc->j;
1360       imat_i    = subc->i;
1361       imat_a    = subc->a;
1362       imat_ilen = subc->ilen;
1363 
1364       if (allcolumns[i]) continue;
1365       jmax = nrow[i];
1366       for (j=0; j<jmax; j++) {
1367         PetscInt ilen;
1368 
1369         mat_i = imat_i[j];
1370         mat_a = imat_a + mat_i;
1371         mat_j = imat_j + mat_i;
1372         ilen  = imat_ilen[j];
1373         ierr  = PetscSortIntWithScalarArray(ilen,mat_j,mat_a);CHKERRQ(ierr);
1374       }
1375     }
1376   }
1377 
1378   ierr = PetscFree(r_status4);CHKERRQ(ierr);
1379   ierr = PetscFree(r_waits4);CHKERRQ(ierr);
1380   if (nrqr) {ierr = MPI_Waitall(nrqr,s_waits4,s_status4);CHKERRQ(ierr);}
1381   ierr = PetscFree(s_waits4);CHKERRQ(ierr);
1382   ierr = PetscFree(s_status4);CHKERRQ(ierr);
1383 
1384   /* Restore the indices */
1385   for (i=0; i<ismax; i++) {
1386     ierr = ISRestoreIndices(isrow[i],irow+i);CHKERRQ(ierr);
1387     if (!allcolumns[i]) {
1388       ierr = ISRestoreIndices(iscol[i],icol+i);CHKERRQ(ierr);
1389     }
1390   }
1391 
1392   for (i=0; i<ismax; i++) {
1393     ierr = MatAssemblyBegin(submats[i],MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1394     ierr = MatAssemblyEnd(submats[i],MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1395   }
1396 
1397   /* Destroy allocated memory */
1398   if (!ismax) {
1399     ierr = PetscFree(pa);CHKERRQ(ierr);
1400 
1401     ierr = PetscFree4(sbuf1,ptr,tmp,ctr);CHKERRQ(ierr);
1402     for (i=0; i<nrqr; ++i) {
1403       ierr = PetscFree(sbuf2[i]);CHKERRQ(ierr);
1404     }
1405     for (i=0; i<nrqs; ++i) {
1406       ierr = PetscFree(rbuf3[i]);CHKERRQ(ierr);
1407     }
1408 
1409     ierr = PetscFree3(sbuf2,req_size,req_source1);CHKERRQ(ierr);
1410     ierr = PetscFree3(req_source2,rbuf2,rbuf3);CHKERRQ(ierr);
1411   }
1412 
1413   ierr = PetscFree(sbuf_aa[0]);CHKERRQ(ierr);
1414   ierr = PetscFree(sbuf_aa);CHKERRQ(ierr);
1415   ierr = PetscFree5(irow,icol,nrow,ncol,issorted);CHKERRQ(ierr);
1416 
1417   for (i=0; i<nrqs; ++i) {
1418     ierr = PetscFree(rbuf4[i]);CHKERRQ(ierr);
1419   }
1420   ierr = PetscFree(rbuf4);CHKERRQ(ierr);
1421 
1422   ierr = PetscFree5(smats,row2proc,cmap,rmap,allcolumns);CHKERRQ(ierr);
1423   PetscFunctionReturn(0);
1424 }
1425 #endif
1426 //------------ endof new -------------
1427 
1428 PetscErrorCode MatGetSubMatrices_MPIBAIJ_local(Mat C,PetscInt ismax,const IS isrow[],const IS iscol[],MatReuse scall,PetscBool *allrows,PetscBool *allcolumns,Mat *submats)
1429 {
1430   Mat_MPIBAIJ    *c = (Mat_MPIBAIJ*)C->data;
1431   Mat            A  = c->A;
1432   Mat_SeqBAIJ    *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ*)c->B->data,*mat;
1433   const PetscInt **irow,**icol,*irow_i;
1434   PetscInt       *nrow,*ncol,*w3,*w4,start;
1435   PetscErrorCode ierr;
1436   PetscMPIInt    size,tag0,tag1,tag2,tag3,*w1,*w2,nrqr,idex,end,proc;
1437   PetscInt       **sbuf1,**sbuf2,rank,i,j,k,l,ct1,ct2,**rbuf1,row;
1438   PetscInt       nrqs,msz,**ptr,*req_size,*ctr,*pa,*tmp,tcol;
1439   PetscInt       **rbuf3,*req_source,**sbuf_aj,**rbuf2,max1,max2;
1440   PetscInt       **lens,is_no,ncols,*cols,mat_i,*mat_j,tmp2,jmax;
1441   PetscInt       ctr_j,*sbuf1_j,*sbuf_aj_i,*rbuf1_i,kmax,*lens_i;
1442   PetscInt       bs     =C->rmap->bs,bs2=c->bs2,*a_j=a->j,*b_j=b->j,*cworkA,*cworkB;
1443   PetscInt       cstart = c->cstartbs,nzA,nzB,*a_i=a->i,*b_i=b->i,imark;
1444   PetscInt       *bmap  = c->garray,ctmp,rstart=c->rstartbs;
1445   MPI_Request    *s_waits1,*r_waits1,*s_waits2,*r_waits2,*r_waits3,*s_waits3;
1446   MPI_Status     *r_status1,*r_status2,*s_status1,*s_status3,*s_status2,*r_status3;
1447   MPI_Comm       comm;
1448   PetscBool      flag;
1449   PetscMPIInt    *onodes1,*olengths1;
1450   PetscBool      ijonly=c->ijonly; /* private flag indicates only matrix data structures are requested */
1451 
1452   /* variables below are used for the matrix numerical values - case of !ijonly */
1453   MPI_Request *r_waits4,*s_waits4;
1454   MPI_Status  *r_status4,*s_status4;
1455   MatScalar   **rbuf4,**sbuf_aa,*vals,*mat_a = NULL,*sbuf_aa_i,*vworkA = NULL,*vworkB = NULL;
1456   MatScalar   *a_a=a->a,*b_a=b->a;
1457 
1458 #if defined(PETSC_USE_CTABLE)
1459   PetscInt   tt;
1460   PetscTable *rmap,*cmap,rmap_i,cmap_i=NULL;
1461 #else
1462   PetscInt **cmap,*cmap_i=NULL,*rtable,*rmap_i,**rmap, Mbs = c->Mbs;
1463 #endif
1464 
1465   PetscFunctionBegin;
1466   ierr = PetscObjectGetComm((PetscObject)C,&comm);CHKERRQ(ierr);
1467   tag0 = ((PetscObject)C)->tag;
1468   size = c->size;
1469   rank = c->rank;
1470   if (!rank) printf("MatGetSubMatrices_MPIBAIJ scall %d, bs %d\n",scall,bs);
1471 
1472   /* Get some new tags to keep the communication clean */
1473   ierr = PetscObjectGetNewTag((PetscObject)C,&tag1);CHKERRQ(ierr);
1474   ierr = PetscObjectGetNewTag((PetscObject)C,&tag2);CHKERRQ(ierr);
1475   ierr = PetscObjectGetNewTag((PetscObject)C,&tag3);CHKERRQ(ierr);
1476 
1477 #if defined(PETSC_USE_CTABLE)
1478   ierr = PetscMalloc4(ismax,&irow,ismax,&icol,ismax,&nrow,ismax,&ncol);CHKERRQ(ierr);
1479 #else
1480   ierr = PetscMalloc5(ismax,&irow,ismax,&icol,ismax,&nrow,ismax,&ncol,Mbs+1,&rtable);CHKERRQ(ierr);
1481   /* Create hash table for the mapping :row -> proc*/
1482   for (i=0,j=0; i<size; i++) {
1483     jmax = C->rmap->range[i+1]/bs;
1484     for (; j<jmax; j++) rtable[j] = i;
1485   }
1486 #endif
1487 
1488   for (i=0; i<ismax; i++) {
1489     if (allrows[i]) {
1490       irow[i] = NULL;
1491       nrow[i] = C->rmap->N/bs;
1492     } else {
1493       ierr = ISGetIndices(isrow[i],&irow[i]);CHKERRQ(ierr);
1494       ierr = ISGetLocalSize(isrow[i],&nrow[i]);CHKERRQ(ierr);
1495     }
1496 
1497     if (allcolumns[i]) {
1498       icol[i] = NULL;
1499       ncol[i] = C->cmap->N/bs;
1500     } else {
1501       ierr = ISGetIndices(iscol[i],&icol[i]);CHKERRQ(ierr);
1502       ierr = ISGetLocalSize(iscol[i],&ncol[i]);CHKERRQ(ierr);
1503     }
1504   }
1505 
1506   /* evaluate communication - mesg to who,length of mesg,and buffer space
1507      required. Based on this, buffers are allocated, and data copied into them*/
1508   ierr = PetscCalloc4(size,&w1,size,&w2,size,&w3,size,&w4);CHKERRQ(ierr);
1509   for (i=0; i<ismax; i++) {
1510     ierr   = PetscMemzero(w4,size*sizeof(PetscInt));CHKERRQ(ierr); /* initialise work vector*/
1511     jmax   = nrow[i];
1512     irow_i = irow[i];
1513     for (j=0; j<jmax; j++) {
1514       if (allrows[i]) row = j;
1515       else row = irow_i[j];
1516 
1517 #if defined(PETSC_USE_CTABLE)
1518       ierr = PetscGetProc(row,size,c->rangebs,&proc);CHKERRQ(ierr);
1519 #else
1520       proc = rtable[row];
1521 #endif
1522       w4[proc]++;
1523     }
1524     for (j=0; j<size; j++) {
1525       if (w4[j]) { w1[j] += w4[j];  w3[j]++;}
1526     }
1527   }
1528 
1529   nrqs     = 0;              /* no of outgoing messages */
1530   msz      = 0;              /* total mesg length for all proc */
1531   w1[rank] = 0;              /* no mesg sent to intself */
1532   w3[rank] = 0;
1533   for (i=0; i<size; i++) {
1534     if (w1[i])  { w2[i] = 1; nrqs++;} /* there exists a message to proc i */
1535   }
1536   ierr = PetscMalloc1(nrqs+1,&pa);CHKERRQ(ierr); /*(proc -array)*/
1537   for (i=0,j=0; i<size; i++) {
1538     if (w1[i]) { pa[j] = i; j++; }
1539   }
1540 
1541   /* Each message would have a header = 1 + 2*(no of IS) + data */
1542   for (i=0; i<nrqs; i++) {
1543     j     = pa[i];
1544     w1[j] += w2[j] + 2* w3[j];
1545     msz   += w1[j];
1546   }
1547 
1548   /* Determine the number of messages to expect, their lengths, from from-ids */
1549   ierr = PetscGatherNumberOfMessages(comm,w2,w1,&nrqr);CHKERRQ(ierr);
1550   ierr = PetscGatherMessageLengths(comm,nrqs,nrqr,w1,&onodes1,&olengths1);CHKERRQ(ierr);
1551 
1552   /* Now post the Irecvs corresponding to these messages */
1553   ierr = PetscPostIrecvInt(comm,tag0,nrqr,onodes1,olengths1,&rbuf1,&r_waits1);CHKERRQ(ierr);
1554 
1555   ierr = PetscFree(onodes1);CHKERRQ(ierr);
1556   ierr = PetscFree(olengths1);CHKERRQ(ierr);
1557 
1558   /* Allocate Memory for outgoing messages */
1559   ierr = PetscMalloc4(size,&sbuf1,size,&ptr,2*msz,&tmp,size,&ctr);CHKERRQ(ierr);
1560   ierr = PetscMemzero(sbuf1,size*sizeof(PetscInt*));CHKERRQ(ierr);
1561   ierr = PetscMemzero(ptr,size*sizeof(PetscInt*));CHKERRQ(ierr);
1562   {
1563     PetscInt *iptr = tmp,ict = 0;
1564     for (i=0; i<nrqs; i++) {
1565       j        = pa[i];
1566       iptr    += ict;
1567       sbuf1[j] = iptr;
1568       ict      = w1[j];
1569     }
1570   }
1571 
1572   /* Form the outgoing messages */
1573   /* Initialise the header space */
1574   for (i=0; i<nrqs; i++) {
1575     j           = pa[i];
1576     sbuf1[j][0] = 0;
1577     ierr        = PetscMemzero(sbuf1[j]+1,2*w3[j]*sizeof(PetscInt));CHKERRQ(ierr);
1578     ptr[j]      = sbuf1[j] + 2*w3[j] + 1;
1579   }
1580 
1581   /* Parse the isrow and copy data into outbuf */
1582   for (i=0; i<ismax; i++) {
1583     ierr   = PetscMemzero(ctr,size*sizeof(PetscInt));CHKERRQ(ierr);
1584     irow_i = irow[i];
1585     jmax   = nrow[i];
1586     for (j=0; j<jmax; j++) {  /* parse the indices of each IS */
1587       if (allrows[i]) row = j;
1588       else row = irow_i[j];
1589 
1590 #if defined(PETSC_USE_CTABLE)
1591       ierr = PetscGetProc(row,size,c->rangebs,&proc);CHKERRQ(ierr);
1592 #else
1593       proc = rtable[row];
1594 #endif
1595       if (proc != rank) { /* copy to the outgoing buf*/
1596         ctr[proc]++;
1597         *ptr[proc] = row;
1598         ptr[proc]++;
1599       }
1600     }
1601     /* Update the headers for the current IS */
1602     for (j=0; j<size; j++) { /* Can Optimise this loop too */
1603       if ((ctr_j = ctr[j])) {
1604         sbuf1_j        = sbuf1[j];
1605         k              = ++sbuf1_j[0];
1606         sbuf1_j[2*k]   = ctr_j;
1607         sbuf1_j[2*k-1] = i;
1608       }
1609     }
1610   }
1611 
1612   /*  Now  post the sends */
1613   ierr = PetscMalloc1(nrqs+1,&s_waits1);CHKERRQ(ierr);
1614   for (i=0; i<nrqs; ++i) {
1615     j    = pa[i];
1616     ierr = MPI_Isend(sbuf1[j],w1[j],MPIU_INT,j,tag0,comm,s_waits1+i);CHKERRQ(ierr);
1617   }
1618 
1619   /* Post Recieves to capture the buffer size */
1620   ierr     = PetscMalloc1(nrqs+1,&r_waits2);CHKERRQ(ierr);
1621   ierr     = PetscMalloc1(nrqs+1,&rbuf2);CHKERRQ(ierr);
1622   rbuf2[0] = tmp + msz;
1623   for (i=1; i<nrqs; ++i) {
1624     rbuf2[i] = rbuf2[i-1]+w1[pa[i-1]];
1625   }
1626   for (i=0; i<nrqs; ++i) {
1627     j        = pa[i];
1628     ierr     = MPI_Irecv(rbuf2[i],w1[j],MPIU_INT,j,tag1,comm,r_waits2+i);CHKERRQ(ierr);
1629   }
1630 
1631   /* Send to other procs the buf size they should allocate */
1632 
1633   /* Receive messages*/
1634   ierr = PetscMalloc1(nrqr+1,&s_waits2);CHKERRQ(ierr);
1635   ierr = PetscMalloc1(nrqr+1,&r_status1);CHKERRQ(ierr);
1636   ierr = PetscMalloc3(nrqr+1,&sbuf2,nrqr,&req_size,nrqr,&req_source);CHKERRQ(ierr);
1637   {
1638     Mat_SeqBAIJ *sA  = (Mat_SeqBAIJ*)c->A->data,*sB = (Mat_SeqBAIJ*)c->B->data;
1639     PetscInt    *sAi = sA->i,*sBi = sB->i,id,*sbuf2_i;
1640 
1641     for (i=0; i<nrqr; ++i) {
1642       ierr = MPI_Waitany(nrqr,r_waits1,&idex,r_status1+i);CHKERRQ(ierr);
1643 
1644       req_size[idex] = 0;
1645       rbuf1_i        = rbuf1[idex];
1646       start          = 2*rbuf1_i[0] + 1;
1647       ierr           = MPI_Get_count(r_status1+i,MPIU_INT,&end);CHKERRQ(ierr);
1648       ierr           = PetscMalloc1(end,&sbuf2[idex]);CHKERRQ(ierr);
1649       sbuf2_i        = sbuf2[idex];
1650       for (j=start; j<end; j++) {
1651         id              = rbuf1_i[j] - rstart;
1652         ncols           = sAi[id+1] - sAi[id] + sBi[id+1] - sBi[id];
1653         sbuf2_i[j]      = ncols;
1654         req_size[idex] += ncols;
1655       }
1656       req_source[idex] = r_status1[i].MPI_SOURCE;
1657       /* form the header */
1658       sbuf2_i[0] = req_size[idex];
1659       for (j=1; j<start; j++) sbuf2_i[j] = rbuf1_i[j];
1660       ierr = MPI_Isend(sbuf2_i,end,MPIU_INT,req_source[idex],tag1,comm,s_waits2+i);CHKERRQ(ierr);
1661     }
1662   }
1663   ierr = PetscFree(r_status1);CHKERRQ(ierr);
1664   ierr = PetscFree(r_waits1);CHKERRQ(ierr);
1665 
1666   /*  recv buffer sizes */
1667   /* Receive messages*/
1668   ierr = PetscMalloc1(nrqs+1,&rbuf3);CHKERRQ(ierr);
1669   ierr = PetscMalloc1(nrqs+1,&r_waits3);CHKERRQ(ierr);
1670   ierr = PetscMalloc1(nrqs+1,&r_status2);CHKERRQ(ierr);
1671   if (!ijonly) {
1672     ierr = PetscMalloc1(nrqs+1,&rbuf4);CHKERRQ(ierr);
1673     ierr = PetscMalloc1(nrqs+1,&r_waits4);CHKERRQ(ierr);
1674   }
1675 
1676   for (i=0; i<nrqs; ++i) {
1677     ierr = MPI_Waitany(nrqs,r_waits2,&idex,r_status2+i);CHKERRQ(ierr);
1678     ierr = PetscMalloc1(rbuf2[idex][0],&rbuf3[idex]);CHKERRQ(ierr);
1679     ierr = MPI_Irecv(rbuf3[idex],rbuf2[idex][0],MPIU_INT,r_status2[i].MPI_SOURCE,tag2,comm,r_waits3+idex);CHKERRQ(ierr);
1680     if (!ijonly) {
1681       ierr = PetscMalloc1(rbuf2[idex][0]*bs2,&rbuf4[idex]);CHKERRQ(ierr);
1682       ierr = MPI_Irecv(rbuf4[idex],rbuf2[idex][0]*bs2,MPIU_MATSCALAR,r_status2[i].MPI_SOURCE,tag3,comm,r_waits4+idex);CHKERRQ(ierr);
1683     }
1684   }
1685   ierr = PetscFree(r_status2);CHKERRQ(ierr);
1686   ierr = PetscFree(r_waits2);CHKERRQ(ierr);
1687 
1688   /* Wait on sends1 and sends2 */
1689   ierr = PetscMalloc1(nrqs+1,&s_status1);CHKERRQ(ierr);
1690   ierr = PetscMalloc1(nrqr+1,&s_status2);CHKERRQ(ierr);
1691 
1692   if (nrqs) {ierr = MPI_Waitall(nrqs,s_waits1,s_status1);CHKERRQ(ierr);}
1693   if (nrqr) {ierr = MPI_Waitall(nrqr,s_waits2,s_status2);CHKERRQ(ierr);}
1694   ierr = PetscFree(s_status1);CHKERRQ(ierr);
1695   ierr = PetscFree(s_status2);CHKERRQ(ierr);
1696   ierr = PetscFree(s_waits1);CHKERRQ(ierr);
1697   ierr = PetscFree(s_waits2);CHKERRQ(ierr);
1698 
1699   /* Now allocate buffers for a->j, and send them off */
1700   ierr = PetscMalloc1(nrqr+1,&sbuf_aj);CHKERRQ(ierr);
1701   for (i=0,j=0; i<nrqr; i++) j += req_size[i];
1702   ierr = PetscMalloc1(j+1,&sbuf_aj[0]);CHKERRQ(ierr);
1703   for (i=1; i<nrqr; i++) sbuf_aj[i] = sbuf_aj[i-1] + req_size[i-1];
1704 
1705   ierr = PetscMalloc1(nrqr+1,&s_waits3);CHKERRQ(ierr);
1706   {
1707     for (i=0; i<nrqr; i++) {
1708       rbuf1_i   = rbuf1[i];
1709       sbuf_aj_i = sbuf_aj[i];
1710       ct1       = 2*rbuf1_i[0] + 1;
1711       ct2       = 0;
1712       for (j=1,max1=rbuf1_i[0]; j<=max1; j++) {
1713         kmax = rbuf1[i][2*j];
1714         for (k=0; k<kmax; k++,ct1++) {
1715           row    = rbuf1_i[ct1] - rstart;
1716           nzA    = a_i[row+1] - a_i[row];
1717           nzB    = b_i[row+1] - b_i[row];
1718           ncols  = nzA + nzB;
1719           cworkA = a_j + a_i[row];
1720           cworkB = b_j + b_i[row];
1721 
1722           /* load the column indices for this row into cols*/
1723           cols = sbuf_aj_i + ct2;
1724           for (l=0; l<nzB; l++) {
1725             if ((ctmp = bmap[cworkB[l]]) < cstart) cols[l] = ctmp;
1726             else break;
1727           }
1728           imark = l;
1729           for (l=0; l<nzA; l++)   cols[imark+l] = cstart + cworkA[l];
1730           for (l=imark; l<nzB; l++) cols[nzA+l] = bmap[cworkB[l]];
1731           ct2 += ncols;
1732         }
1733       }
1734       ierr = MPI_Isend(sbuf_aj_i,req_size[i],MPIU_INT,req_source[i],tag2,comm,s_waits3+i);CHKERRQ(ierr);
1735     }
1736   }
1737   ierr = PetscMalloc1(nrqs+1,&r_status3);CHKERRQ(ierr);
1738   ierr = PetscMalloc1(nrqr+1,&s_status3);CHKERRQ(ierr);
1739 
1740   /* Allocate buffers for a->a, and send them off */
1741   if (!ijonly) {
1742     ierr = PetscMalloc1(nrqr+1,&sbuf_aa);CHKERRQ(ierr);
1743     for (i=0,j=0; i<nrqr; i++) j += req_size[i];
1744     ierr = PetscMalloc1((j+1)*bs2,&sbuf_aa[0]);CHKERRQ(ierr);
1745     for (i=1; i<nrqr; i++) sbuf_aa[i] = sbuf_aa[i-1] + req_size[i-1]*bs2;
1746 
1747     ierr = PetscMalloc1(nrqr+1,&s_waits4);CHKERRQ(ierr);
1748     {
1749       for (i=0; i<nrqr; i++) {
1750         rbuf1_i   = rbuf1[i];
1751         sbuf_aa_i = sbuf_aa[i];
1752         ct1       = 2*rbuf1_i[0]+1;
1753         ct2       = 0;
1754         for (j=1,max1=rbuf1_i[0]; j<=max1; j++) {
1755           kmax = rbuf1_i[2*j];
1756           for (k=0; k<kmax; k++,ct1++) {
1757             row    = rbuf1_i[ct1] - rstart;
1758             nzA    = a_i[row+1] - a_i[row];
1759             nzB    = b_i[row+1] - b_i[row];
1760             ncols  = nzA + nzB;
1761             cworkB = b_j + b_i[row];
1762             vworkA = a_a + a_i[row]*bs2;
1763             vworkB = b_a + b_i[row]*bs2;
1764 
1765             /* load the column values for this row into vals*/
1766             vals = sbuf_aa_i+ct2*bs2;
1767             for (l=0; l<nzB; l++) {
1768               if ((bmap[cworkB[l]]) < cstart) {
1769                 ierr = PetscMemcpy(vals+l*bs2,vworkB+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
1770               } else break;
1771             }
1772             imark = l;
1773             for (l=0; l<nzA; l++) {
1774               ierr = PetscMemcpy(vals+(imark+l)*bs2,vworkA+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
1775             }
1776             for (l=imark; l<nzB; l++) {
1777               ierr = PetscMemcpy(vals+(nzA+l)*bs2,vworkB+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
1778             }
1779             ct2 += ncols;
1780           }
1781         }
1782         ierr = MPI_Isend(sbuf_aa_i,req_size[i]*bs2,MPIU_MATSCALAR,req_source[i],tag3,comm,s_waits4+i);CHKERRQ(ierr);
1783       }
1784     }
1785     ierr = PetscMalloc1(nrqs+1,&r_status4);CHKERRQ(ierr);
1786     ierr = PetscMalloc1(nrqr+1,&s_status4);CHKERRQ(ierr);
1787   }
1788   ierr = PetscFree(rbuf1[0]);CHKERRQ(ierr);
1789   ierr = PetscFree(rbuf1);CHKERRQ(ierr);
1790 
1791   /* Form the matrix */
1792   /* create col map: global col of C -> local col of submatrices */
1793   {
1794     const PetscInt *icol_i;
1795 #if defined(PETSC_USE_CTABLE)
1796     ierr = PetscMalloc1(1+ismax,&cmap);CHKERRQ(ierr);
1797     for (i=0; i<ismax; i++) {
1798       if (!allcolumns[i]) {
1799         ierr   = PetscTableCreate(ncol[i]+1,c->Nbs+1,&cmap[i]);CHKERRQ(ierr);
1800         jmax   = ncol[i];
1801         icol_i = icol[i];
1802         cmap_i = cmap[i];
1803         for (j=0; j<jmax; j++) {
1804           ierr = PetscTableAdd(cmap_i,icol_i[j]+1,j+1,INSERT_VALUES);CHKERRQ(ierr);
1805         }
1806       } else {
1807         cmap[i] = NULL;
1808       }
1809     }
1810 #else
1811     ierr = PetscMalloc1(ismax,&cmap);CHKERRQ(ierr);
1812     for (i=0; i<ismax; i++) {
1813       if (!allcolumns[i]) {
1814         ierr   = PetscCalloc1(c->Nbs,&cmap[i]);CHKERRQ(ierr);
1815         jmax   = ncol[i];
1816         icol_i = icol[i];
1817         cmap_i = cmap[i];
1818         for (j=0; j<jmax; j++) {
1819           cmap_i[icol_i[j]] = j+1;
1820         }
1821       } else { /* allcolumns[i] */
1822         cmap[i] = NULL;
1823       }
1824     }
1825 #endif
1826   }
1827 
1828   /* Create lens which is required for MatCreate... */
1829   for (i=0,j=0; i<ismax; i++) j += nrow[i];
1830   ierr    = PetscMalloc((1+ismax)*sizeof(PetscInt*)+ j*sizeof(PetscInt),&lens);CHKERRQ(ierr);
1831   lens[0] = (PetscInt*)(lens + ismax);
1832   ierr    = PetscMemzero(lens[0],j*sizeof(PetscInt));CHKERRQ(ierr);
1833   for (i=1; i<ismax; i++) lens[i] = lens[i-1] + nrow[i-1];
1834 
1835   /* Update lens from local data */
1836   for (i=0; i<ismax; i++) {
1837     jmax = nrow[i];
1838     if (!allcolumns[i]) cmap_i = cmap[i];
1839     irow_i = irow[i];
1840     lens_i = lens[i];
1841     for (j=0; j<jmax; j++) {
1842       if (allrows[i]) row = j;
1843       else row = irow_i[j];
1844 
1845 #if defined(PETSC_USE_CTABLE)
1846       ierr = PetscGetProc(row,size,c->rangebs,&proc);CHKERRQ(ierr);
1847 #else
1848       proc = rtable[row];
1849 #endif
1850       if (proc == rank) {
1851         /* Get indices from matA and then from matB */
1852         row    = row - rstart;
1853         nzA    = a_i[row+1] - a_i[row];
1854         nzB    = b_i[row+1] - b_i[row];
1855         cworkA =  a_j + a_i[row];
1856         cworkB = b_j + b_i[row];
1857         if (!allcolumns[i]) {
1858 #if defined(PETSC_USE_CTABLE)
1859           for (k=0; k<nzA; k++) {
1860             ierr = PetscTableFind(cmap_i,cstart+cworkA[k]+1,&tt);CHKERRQ(ierr);
1861             if (tt) lens_i[j]++;
1862           }
1863           for (k=0; k<nzB; k++) {
1864             ierr = PetscTableFind(cmap_i,bmap[cworkB[k]]+1,&tt);CHKERRQ(ierr);
1865             if (tt) lens_i[j]++;
1866           }
1867 
1868 #else
1869           for (k=0; k<nzA; k++) {
1870             if (cmap_i[cstart + cworkA[k]]) lens_i[j]++;
1871           }
1872           for (k=0; k<nzB; k++) {
1873             if (cmap_i[bmap[cworkB[k]]]) lens_i[j]++;
1874           }
1875 #endif
1876         } else { /* allcolumns */
1877           lens_i[j] = nzA + nzB;
1878         }
1879       }
1880     }
1881   }
1882 #if defined(PETSC_USE_CTABLE)
1883   /* Create row map*/
1884   ierr = PetscMalloc1(1+ismax,&rmap);CHKERRQ(ierr);
1885   for (i=0; i<ismax; i++) {
1886     ierr = PetscTableCreate(nrow[i]+1,c->Mbs+1,&rmap[i]);CHKERRQ(ierr);
1887   }
1888 #else
1889   /* Create row map*/
1890   ierr    = PetscMalloc((1+ismax)*sizeof(PetscInt*)+ ismax*Mbs*sizeof(PetscInt),&rmap);CHKERRQ(ierr);
1891   rmap[0] = (PetscInt*)(rmap + ismax);
1892   ierr    = PetscMemzero(rmap[0],ismax*Mbs*sizeof(PetscInt));CHKERRQ(ierr);
1893   for (i=1; i<ismax; i++) rmap[i] = rmap[i-1] + Mbs;
1894 #endif
1895   for (i=0; i<ismax; i++) {
1896     irow_i = irow[i];
1897     jmax   = nrow[i];
1898 #if defined(PETSC_USE_CTABLE)
1899     rmap_i = rmap[i];
1900     for (j=0; j<jmax; j++) {
1901       if (allrows[i]) {
1902         ierr = PetscTableAdd(rmap_i,j+1,j+1,INSERT_VALUES);CHKERRQ(ierr);
1903       } else {
1904         ierr = PetscTableAdd(rmap_i,irow_i[j]+1,j+1,INSERT_VALUES);CHKERRQ(ierr);
1905       }
1906     }
1907 #else
1908     rmap_i = rmap[i];
1909     for (j=0; j<jmax; j++) {
1910       if (allrows[i]) rmap_i[j] = j;
1911       else rmap_i[irow_i[j]] = j;
1912     }
1913 #endif
1914   }
1915 
1916   /* Update lens from offproc data */
1917   {
1918     PetscInt    *rbuf2_i,*rbuf3_i,*sbuf1_i;
1919     PetscMPIInt ii;
1920 
1921     for (tmp2=0; tmp2<nrqs; tmp2++) {
1922       ierr    = MPI_Waitany(nrqs,r_waits3,&ii,r_status3+tmp2);CHKERRQ(ierr);
1923       idex    = pa[ii];
1924       sbuf1_i = sbuf1[idex];
1925       jmax    = sbuf1_i[0];
1926       ct1     = 2*jmax+1;
1927       ct2     = 0;
1928       rbuf2_i = rbuf2[ii];
1929       rbuf3_i = rbuf3[ii];
1930       for (j=1; j<=jmax; j++) {
1931         is_no  = sbuf1_i[2*j-1];
1932         max1   = sbuf1_i[2*j];
1933         lens_i = lens[is_no];
1934         if (!allcolumns[is_no]) cmap_i = cmap[is_no];
1935         rmap_i = rmap[is_no];
1936         for (k=0; k<max1; k++,ct1++) {
1937 #if defined(PETSC_USE_CTABLE)
1938           ierr = PetscTableFind(rmap_i,sbuf1_i[ct1]+1,&row);CHKERRQ(ierr);
1939           row--;
1940           if (row < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"row not found in table");
1941 #else
1942           row = rmap_i[sbuf1_i[ct1]];  /* the val in the new matrix to be */
1943 #endif
1944           max2 = rbuf2_i[ct1];
1945           for (l=0; l<max2; l++,ct2++) {
1946             if (!allcolumns[is_no]) {
1947 #if defined(PETSC_USE_CTABLE)
1948               ierr = PetscTableFind(cmap_i,rbuf3_i[ct2]+1,&tt);CHKERRQ(ierr);
1949               if (tt) lens_i[row]++;
1950 #else
1951               if (cmap_i[rbuf3_i[ct2]]) lens_i[row]++;
1952 #endif
1953             } else { /* allcolumns */
1954               lens_i[row]++;
1955             }
1956           }
1957         }
1958       }
1959     }
1960   }
1961   ierr = PetscFree(r_status3);CHKERRQ(ierr);
1962   ierr = PetscFree(r_waits3);CHKERRQ(ierr);
1963   if (nrqr) {ierr = MPI_Waitall(nrqr,s_waits3,s_status3);CHKERRQ(ierr);}
1964   ierr = PetscFree(s_status3);CHKERRQ(ierr);
1965   ierr = PetscFree(s_waits3);CHKERRQ(ierr);
1966 
1967   /* Create the submatrices */
1968   if (scall == MAT_REUSE_MATRIX) {
1969     if (ijonly) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP," MAT_REUSE_MATRIX and ijonly is not supported yet");
1970     /*
1971         Assumes new rows are same length as the old rows, hence bug!
1972     */
1973     for (i=0; i<ismax; i++) {
1974       mat = (Mat_SeqBAIJ*)(submats[i]->data);
1975       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");
1976       ierr = PetscMemcmp(mat->ilen,lens[i],mat->mbs *sizeof(PetscInt),&flag);CHKERRQ(ierr);
1977       if (!flag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_INCOMP,"Cannot reuse matrix. wrong no of nonzeros");
1978       /* Initial matrix as if empty */
1979       ierr = PetscMemzero(mat->ilen,mat->mbs*sizeof(PetscInt));CHKERRQ(ierr);
1980 
1981       submats[i]->factortype = C->factortype;
1982     }
1983   } else {
1984     PetscInt bs_tmp;
1985     if (ijonly) bs_tmp = 1;
1986     else        bs_tmp = bs;
1987     for (i=0; i<ismax; i++) {
1988       ierr = MatCreate(PETSC_COMM_SELF,submats+i);CHKERRQ(ierr);
1989       ierr = MatSetSizes(submats[i],nrow[i]*bs_tmp,ncol[i]*bs_tmp,nrow[i]*bs_tmp,ncol[i]*bs_tmp);CHKERRQ(ierr);
1990       ierr = MatSetType(submats[i],((PetscObject)A)->type_name);CHKERRQ(ierr);
1991       ierr = MatSeqBAIJSetPreallocation(submats[i],bs_tmp,0,lens[i]);CHKERRQ(ierr);
1992       ierr = MatSeqSBAIJSetPreallocation(submats[i],bs_tmp,0,lens[i]);CHKERRQ(ierr); /* this subroutine is used by SBAIJ routines */
1993     }
1994   }
1995 
1996   /* Assemble the matrices */
1997   /* First assemble the local rows */
1998   {
1999     PetscInt  ilen_row,*imat_ilen,*imat_j,*imat_i;
2000     MatScalar *imat_a = NULL;
2001 
2002     for (i=0; i<ismax; i++) {
2003       mat       = (Mat_SeqBAIJ*)submats[i]->data;
2004       imat_ilen = mat->ilen;
2005       imat_j    = mat->j;
2006       imat_i    = mat->i;
2007       if (!ijonly) imat_a = mat->a;
2008       if (!allcolumns[i]) cmap_i = cmap[i];
2009       rmap_i = rmap[i];
2010       irow_i = irow[i];
2011       jmax   = nrow[i];
2012       for (j=0; j<jmax; j++) {
2013         if (allrows[i]) row = j;
2014         else row = irow_i[j];
2015 
2016 #if defined(PETSC_USE_CTABLE)
2017         ierr = PetscGetProc(row,size,c->rangebs,&proc);CHKERRQ(ierr);
2018 #else
2019         proc = rtable[row];
2020 #endif
2021         if (proc == rank) {
2022           row    = row - rstart;
2023           nzA    = a_i[row+1] - a_i[row];
2024           nzB    = b_i[row+1] - b_i[row];
2025           cworkA = a_j + a_i[row];
2026           cworkB = b_j + b_i[row];
2027           if (!ijonly) {
2028             vworkA = a_a + a_i[row]*bs2;
2029             vworkB = b_a + b_i[row]*bs2;
2030           }
2031 #if defined(PETSC_USE_CTABLE)
2032           ierr = PetscTableFind(rmap_i,row+rstart+1,&row);CHKERRQ(ierr);
2033           row--;
2034           if (row < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"row not found in table");
2035 #else
2036           row = rmap_i[row + rstart];
2037 #endif
2038           mat_i = imat_i[row];
2039           if (!ijonly) mat_a = imat_a + mat_i*bs2;
2040           mat_j    = imat_j + mat_i;
2041           ilen_row = imat_ilen[row];
2042 
2043           /* load the column indices for this row into cols*/
2044           if (!allcolumns[i]) {
2045             for (l=0; l<nzB; l++) {
2046               if ((ctmp = bmap[cworkB[l]]) < cstart) {
2047 #if defined(PETSC_USE_CTABLE)
2048                 ierr = PetscTableFind(cmap_i,ctmp+1,&tcol);CHKERRQ(ierr);
2049                 if (tcol) {
2050 #else
2051                 if ((tcol = cmap_i[ctmp])) {
2052 #endif
2053                   *mat_j++ = tcol - 1;
2054                   ierr     = PetscMemcpy(mat_a,vworkB+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
2055                   mat_a   += bs2;
2056                   ilen_row++;
2057                 }
2058               } else break;
2059             }
2060             imark = l;
2061             for (l=0; l<nzA; l++) {
2062 #if defined(PETSC_USE_CTABLE)
2063               ierr = PetscTableFind(cmap_i,cstart+cworkA[l]+1,&tcol);CHKERRQ(ierr);
2064               if (tcol) {
2065 #else
2066               if ((tcol = cmap_i[cstart + cworkA[l]])) {
2067 #endif
2068                 *mat_j++ = tcol - 1;
2069                 if (!ijonly) {
2070                   ierr   = PetscMemcpy(mat_a,vworkA+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
2071                   mat_a += bs2;
2072                 }
2073                 ilen_row++;
2074               }
2075             }
2076             for (l=imark; l<nzB; l++) {
2077 #if defined(PETSC_USE_CTABLE)
2078               ierr = PetscTableFind(cmap_i,bmap[cworkB[l]]+1,&tcol);CHKERRQ(ierr);
2079               if (tcol) {
2080 #else
2081               if ((tcol = cmap_i[bmap[cworkB[l]]])) {
2082 #endif
2083                 *mat_j++ = tcol - 1;
2084                 if (!ijonly) {
2085                   ierr   = PetscMemcpy(mat_a,vworkB+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
2086                   mat_a += bs2;
2087                 }
2088                 ilen_row++;
2089               }
2090             }
2091           } else { /* allcolumns */
2092             for (l=0; l<nzB; l++) {
2093               if ((ctmp = bmap[cworkB[l]]) < cstart) {
2094                 *mat_j++ = ctmp;
2095                 ierr     = PetscMemcpy(mat_a,vworkB+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
2096                 mat_a   += bs2;
2097                 ilen_row++;
2098               } else break;
2099             }
2100             imark = l;
2101             for (l=0; l<nzA; l++) {
2102               *mat_j++ = cstart+cworkA[l];
2103               if (!ijonly) {
2104                 ierr   = PetscMemcpy(mat_a,vworkA+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
2105                 mat_a += bs2;
2106               }
2107               ilen_row++;
2108             }
2109             for (l=imark; l<nzB; l++) {
2110               *mat_j++ = bmap[cworkB[l]];
2111               if (!ijonly) {
2112                 ierr   = PetscMemcpy(mat_a,vworkB+l*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
2113                 mat_a += bs2;
2114               }
2115               ilen_row++;
2116             }
2117           }
2118           imat_ilen[row] = ilen_row;
2119         }
2120       }
2121     }
2122   }
2123 
2124   /*   Now assemble the off proc rows*/
2125   {
2126     PetscInt    *sbuf1_i,*rbuf2_i,*rbuf3_i,*imat_ilen,ilen;
2127     PetscInt    *imat_j,*imat_i;
2128     MatScalar   *imat_a = NULL,*rbuf4_i = NULL;
2129     PetscMPIInt ii;
2130 
2131     for (tmp2=0; tmp2<nrqs; tmp2++) {
2132       if (ijonly) ii = tmp2;
2133       else {
2134         ierr = MPI_Waitany(nrqs,r_waits4,&ii,r_status4+tmp2);CHKERRQ(ierr);
2135       }
2136       idex    = pa[ii];
2137       sbuf1_i = sbuf1[idex];
2138       jmax    = sbuf1_i[0];
2139       ct1     = 2*jmax + 1;
2140       ct2     = 0;
2141       rbuf2_i = rbuf2[ii];
2142       rbuf3_i = rbuf3[ii];
2143       if (!ijonly) rbuf4_i = rbuf4[ii];
2144       for (j=1; j<=jmax; j++) {
2145         is_no = sbuf1_i[2*j-1];
2146         if (!allcolumns[is_no]) cmap_i = cmap[is_no];
2147         rmap_i    = rmap[is_no];
2148         mat       = (Mat_SeqBAIJ*)submats[is_no]->data;
2149         imat_ilen = mat->ilen;
2150         imat_j    = mat->j;
2151         imat_i    = mat->i;
2152         if (!ijonly) imat_a = mat->a;
2153         max1 = sbuf1_i[2*j];
2154         for (k=0; k<max1; k++,ct1++) {
2155           row = sbuf1_i[ct1];
2156 #if defined(PETSC_USE_CTABLE)
2157           ierr = PetscTableFind(rmap_i,row+1,&row);CHKERRQ(ierr);
2158           row--;
2159           if (row < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"row not found in table");
2160 #else
2161           row = rmap_i[row];
2162 #endif
2163           ilen  = imat_ilen[row];
2164           mat_i = imat_i[row];
2165           if (!ijonly) mat_a = imat_a + mat_i*bs2;
2166           mat_j = imat_j + mat_i;
2167           max2  = rbuf2_i[ct1];
2168 
2169           if (!allcolumns[is_no]) {
2170             for (l=0; l<max2; l++,ct2++) {
2171 #if defined(PETSC_USE_CTABLE)
2172               ierr = PetscTableFind(cmap_i,rbuf3_i[ct2]+1,&tcol);CHKERRQ(ierr);
2173               if (tcol) {
2174 #else
2175               if ((tcol = cmap_i[rbuf3_i[ct2]])) {
2176 #endif
2177                 *mat_j++ = tcol - 1;
2178                 if (!ijonly) {
2179                   ierr   = PetscMemcpy(mat_a,rbuf4_i+ct2*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
2180                   mat_a += bs2;
2181                 }
2182                 ilen++;
2183               }
2184             }
2185           } else { /* allcolumns */
2186             for (l=0; l<max2; l++,ct2++) {
2187               *mat_j++ = rbuf3_i[ct2];
2188               if (!ijonly) {
2189                 ierr   = PetscMemcpy(mat_a,rbuf4_i+ct2*bs2,bs2*sizeof(MatScalar));CHKERRQ(ierr);
2190                 mat_a += bs2;
2191               }
2192               ilen++;
2193             }
2194           }
2195           imat_ilen[row] = ilen;
2196         }
2197       }
2198     }
2199   }
2200   /* sort the rows */
2201   {
2202     PetscInt  ilen_row,*imat_ilen,*imat_j,*imat_i;
2203     MatScalar *imat_a = NULL;
2204     MatScalar *work;
2205 
2206     ierr = PetscMalloc1(bs2,&work);CHKERRQ(ierr);
2207     for (i=0; i<ismax; i++) {
2208       mat       = (Mat_SeqBAIJ*)submats[i]->data;
2209       imat_ilen = mat->ilen;
2210       imat_j    = mat->j;
2211       imat_i    = mat->i;
2212       if (!ijonly) imat_a = mat->a;
2213       if (allcolumns[i]) continue;
2214       jmax   = nrow[i];
2215       for (j=0; j<jmax; j++) {
2216         mat_i = imat_i[j];
2217         if (!ijonly) mat_a = imat_a + mat_i*bs2;
2218         mat_j    = imat_j + mat_i;
2219         ilen_row = imat_ilen[j];
2220         if (!ijonly) {ierr = PetscSortIntWithDataArray(ilen_row,mat_j,mat_a,bs2*sizeof(MatScalar),work);CHKERRQ(ierr);}
2221         else {ierr = PetscSortInt(ilen_row,mat_j);CHKERRQ(ierr);}
2222       }
2223     }
2224     ierr = PetscFree(work);CHKERRQ(ierr);
2225   }
2226   if (!ijonly) {
2227     ierr = PetscFree(r_status4);CHKERRQ(ierr);
2228     ierr = PetscFree(r_waits4);CHKERRQ(ierr);
2229     if (nrqr) {ierr = MPI_Waitall(nrqr,s_waits4,s_status4);CHKERRQ(ierr);}
2230     ierr = PetscFree(s_waits4);CHKERRQ(ierr);
2231     ierr = PetscFree(s_status4);CHKERRQ(ierr);
2232   }
2233 
2234   /* Restore the indices */
2235   for (i=0; i<ismax; i++) {
2236     if (!allrows[i]) {
2237       ierr = ISRestoreIndices(isrow[i],irow+i);CHKERRQ(ierr);
2238     }
2239     if (!allcolumns[i]) {
2240       ierr = ISRestoreIndices(iscol[i],icol+i);CHKERRQ(ierr);
2241     }
2242   }
2243 
2244   /* Destroy allocated memory */
2245 #if defined(PETSC_USE_CTABLE)
2246   ierr = PetscFree4(irow,icol,nrow,ncol);CHKERRQ(ierr);
2247 #else
2248   ierr = PetscFree5(irow,icol,nrow,ncol,rtable);CHKERRQ(ierr);
2249 #endif
2250   ierr = PetscFree4(w1,w2,w3,w4);CHKERRQ(ierr);
2251   ierr = PetscFree(pa);CHKERRQ(ierr);
2252 
2253   ierr = PetscFree4(sbuf1,ptr,tmp,ctr);CHKERRQ(ierr);
2254   ierr = PetscFree(sbuf1);CHKERRQ(ierr);
2255   ierr = PetscFree(rbuf2);CHKERRQ(ierr);
2256   for (i=0; i<nrqr; ++i) {
2257     ierr = PetscFree(sbuf2[i]);CHKERRQ(ierr);
2258   }
2259   for (i=0; i<nrqs; ++i) {
2260     ierr = PetscFree(rbuf3[i]);CHKERRQ(ierr);
2261   }
2262   ierr = PetscFree3(sbuf2,req_size,req_source);CHKERRQ(ierr);
2263   ierr = PetscFree(rbuf3);CHKERRQ(ierr);
2264   ierr = PetscFree(sbuf_aj[0]);CHKERRQ(ierr);
2265   ierr = PetscFree(sbuf_aj);CHKERRQ(ierr);
2266   if (!ijonly) {
2267     for (i=0; i<nrqs; ++i) {ierr = PetscFree(rbuf4[i]);CHKERRQ(ierr);}
2268     ierr = PetscFree(rbuf4);CHKERRQ(ierr);
2269     ierr = PetscFree(sbuf_aa[0]);CHKERRQ(ierr);
2270     ierr = PetscFree(sbuf_aa);CHKERRQ(ierr);
2271   }
2272 
2273 #if defined(PETSC_USE_CTABLE)
2274   for (i=0; i<ismax; i++) {
2275     ierr = PetscTableDestroy((PetscTable*)&rmap[i]);CHKERRQ(ierr);
2276   }
2277 #endif
2278   ierr = PetscFree(rmap);CHKERRQ(ierr);
2279 
2280   for (i=0; i<ismax; i++) {
2281     if (!allcolumns[i]) {
2282 #if defined(PETSC_USE_CTABLE)
2283       ierr = PetscTableDestroy((PetscTable*)&cmap[i]);CHKERRQ(ierr);
2284 #else
2285       ierr = PetscFree(cmap[i]);CHKERRQ(ierr);
2286 #endif
2287     }
2288   }
2289   ierr = PetscFree(cmap);CHKERRQ(ierr);
2290   ierr = PetscFree(lens);CHKERRQ(ierr);
2291 
2292   for (i=0; i<ismax; i++) {
2293     ierr = MatAssemblyBegin(submats[i],MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2294     ierr = MatAssemblyEnd(submats[i],MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2295   }
2296 
2297   c->ijonly = PETSC_FALSE; /* set back to the default */
2298   PetscFunctionReturn(0);
2299 }
2300 
2301