Actual source code: sbaijov.c
1: /*
2: Routines to compute overlapping regions of a parallel MPI matrix.
3: Used for finding submatrices that were shared across processors.
4: */
5: #include <../src/mat/impls/sbaij/mpi/mpisbaij.h>
6: #include <petscbt.h>
8: static PetscErrorCode MatIncreaseOverlap_MPISBAIJ_Once(Mat, PetscInt, IS *);
9: static PetscErrorCode MatIncreaseOverlap_MPISBAIJ_Local(Mat, PetscInt *, PetscInt, PetscInt *, PetscBT *);
11: PetscErrorCode MatIncreaseOverlap_MPISBAIJ(Mat C, PetscInt is_max, IS is[], PetscInt ov)
12: {
13: PetscInt i, N = C->cmap->N, bs = C->rmap->bs, M = C->rmap->N, Mbs = M / bs, *nidx, isz, iov;
14: IS *is_new, *is_row;
15: Mat *submats;
16: Mat_MPISBAIJ *c = (Mat_MPISBAIJ *)C->data;
17: Mat_SeqSBAIJ *asub_i;
18: PetscBT table;
19: PetscInt *ai, brow, nz, nis, l, nmax, nstages_local, nstages, max_no, pos;
20: const PetscInt *idx;
21: PetscBool flg;
23: PetscFunctionBegin;
24: PetscCall(PetscMalloc1(is_max, &is_new));
25: /* Convert the indices into block format */
26: PetscCall(ISCompressIndicesGeneral(N, C->rmap->n, bs, is_max, is, is_new));
27: PetscCheck(ov >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Negative overlap specified");
29: /* previous non-scalable implementation */
30: flg = PETSC_FALSE;
31: PetscCall(PetscOptionsHasName(NULL, NULL, "-IncreaseOverlap_old", &flg));
32: if (flg) { /* previous non-scalable implementation */
33: printf("use previous non-scalable implementation...\n");
34: for (i = 0; i < ov; ++i) PetscCall(MatIncreaseOverlap_MPISBAIJ_Once(C, is_max, is_new));
35: } else { /* implementation using modified BAIJ routines */
37: PetscCall(PetscMalloc1(Mbs + 1, &nidx));
38: PetscCall(PetscBTCreate(Mbs, &table)); /* for column search */
40: /* Create is_row */
41: PetscCall(PetscMalloc1(is_max, &is_row));
42: PetscCall(ISCreateStride(PETSC_COMM_SELF, Mbs, 0, 1, &is_row[0]));
44: for (i = 1; i < is_max; i++) { is_row[i] = is_row[0]; /* reuse is_row[0] */ }
46: /* Allocate memory to hold all the submatrices - Modified from MatCreateSubMatrices_MPIBAIJ() */
47: PetscCall(PetscMalloc1(is_max + 1, &submats));
49: /* Determine the number of stages through which submatrices are done */
50: nmax = 20 * 1000000 / (c->Nbs * sizeof(PetscInt));
51: if (!nmax) nmax = 1;
52: nstages_local = is_max / nmax + ((is_max % nmax) ? 1 : 0);
54: /* Make sure every processor loops through the nstages */
55: PetscCall(MPIU_Allreduce(&nstages_local, &nstages, 1, MPIU_INT, MPI_MAX, PetscObjectComm((PetscObject)C)));
57: {
58: const PetscObject obj = (PetscObject)c->A;
59: size_t new_len, cur_len, max_len;
61: PetscCall(PetscStrlen(MATSEQBAIJ, &new_len));
62: PetscCall(PetscStrlen(MATSEQSBAIJ, &cur_len));
63: max_len = PetscMax(cur_len, new_len) + 1;
64: PetscCall(PetscRealloc(max_len * sizeof(*obj->type_name), &obj->type_name));
65: /* The resulting submatrices should be BAIJ, not SBAIJ, hence we change this value to
66: trigger that */
67: for (iov = 0; iov < ov; ++iov) {
68: /* 1) Get submats for column search */
69: PetscCall(PetscStrncpy(obj->type_name, MATSEQBAIJ, max_len));
70: for (i = 0, pos = 0; i < nstages; i++) {
71: if (pos + nmax <= is_max) max_no = nmax;
72: else if (pos == is_max) max_no = 0;
73: else max_no = is_max - pos;
74: c->ijonly = PETSC_TRUE; /* only matrix data structures are requested */
76: PetscCall(MatCreateSubMatrices_MPIBAIJ_local(C, max_no, is_row + pos, is_new + pos, MAT_INITIAL_MATRIX, submats + pos, PETSC_TRUE));
77: pos += max_no;
78: }
79: PetscCall(PetscStrncpy(obj->type_name, MATSEQSBAIJ, max_len));
81: /* 2) Row search */
82: PetscCall(MatIncreaseOverlap_MPIBAIJ_Once(C, is_max, is_new));
84: /* 3) Column search */
85: for (i = 0; i < is_max; i++) {
86: asub_i = (Mat_SeqSBAIJ *)submats[i]->data;
87: ai = asub_i->i;
89: /* put is_new obtained from MatIncreaseOverlap_MPIBAIJ() to table */
90: PetscCall(PetscBTMemzero(Mbs, table));
92: PetscCall(ISGetIndices(is_new[i], &idx));
93: PetscCall(ISGetLocalSize(is_new[i], &nis));
94: for (l = 0; l < nis; l++) {
95: PetscCall(PetscBTSet(table, idx[l]));
96: nidx[l] = idx[l];
97: }
98: isz = nis;
100: /* add column entries to table */
101: for (brow = 0; brow < Mbs; brow++) {
102: nz = ai[brow + 1] - ai[brow];
103: if (nz) {
104: if (!PetscBTLookupSet(table, brow)) nidx[isz++] = brow;
105: }
106: }
107: PetscCall(ISRestoreIndices(is_new[i], &idx));
108: PetscCall(ISDestroy(&is_new[i]));
110: /* create updated is_new */
111: PetscCall(ISCreateGeneral(PETSC_COMM_SELF, isz, nidx, PETSC_COPY_VALUES, is_new + i));
112: }
114: /* Free tmp spaces */
115: for (i = 0; i < is_max; i++) PetscCall(MatDestroy(&submats[i]));
116: }
118: PetscCall(PetscBTDestroy(&table));
119: PetscCall(PetscFree(submats));
120: PetscCall(ISDestroy(&is_row[0]));
121: PetscCall(PetscFree(is_row));
122: PetscCall(PetscFree(nidx));
123: }
124: }
125: for (i = 0; i < is_max; i++) {
126: PetscCall(ISDestroy(&is[i]));
127: PetscCall(ISGetLocalSize(is_new[i], &nis));
128: PetscCall(ISGetIndices(is_new[i], &idx));
129: PetscCall(ISCreateBlock(PetscObjectComm((PetscObject)is_new[i]), bs, nis, idx, PETSC_COPY_VALUES, &is[i]));
130: PetscCall(ISDestroy(&is_new[i]));
131: }
132: PetscCall(PetscFree(is_new));
133: PetscFunctionReturn(PETSC_SUCCESS);
134: }
136: typedef enum {
137: MINE,
138: OTHER
139: } WhoseOwner;
140: /* data1, odata1 and odata2 are packed in the format (for communication):
141: data[0] = is_max, no of is
142: data[1] = size of is[0]
143: ...
144: data[is_max] = size of is[is_max-1]
145: data[is_max + 1] = data(is[0])
146: ...
147: data[is_max+1+sum(size of is[k]), k=0,...,i-1] = data(is[i])
148: ...
149: data2 is packed in the format (for creating output is[]):
150: data[0] = is_max, no of is
151: data[1] = size of is[0]
152: ...
153: data[is_max] = size of is[is_max-1]
154: data[is_max + 1] = data(is[0])
155: ...
156: data[is_max + 1 + Mbs*i) = data(is[i])
157: ...
158: */
159: static PetscErrorCode MatIncreaseOverlap_MPISBAIJ_Once(Mat C, PetscInt is_max, IS is[])
160: {
161: Mat_MPISBAIJ *c = (Mat_MPISBAIJ *)C->data;
162: PetscMPIInt size, rank, tag1, tag2, *len_s, nrqr, nrqs, *id_r1, *len_r1, flag, len, *iwork;
163: const PetscInt *idx_i;
164: PetscInt idx, isz, col, *n, *data1, **data1_start, *data2, *data2_i, *data, *data_i;
165: PetscInt Mbs, i, j, k, *odata1, *odata2;
166: PetscInt proc_id, **odata2_ptr, *ctable = NULL, *btable, len_max, len_est;
167: PetscInt proc_end = 0, len_unused, nodata2;
168: PetscInt ois_max; /* max no of is[] in each of processor */
169: char *t_p;
170: MPI_Comm comm;
171: MPI_Request *s_waits1, *s_waits2, r_req;
172: MPI_Status *s_status, r_status;
173: PetscBT *table; /* mark indices of this processor's is[] */
174: PetscBT table_i;
175: PetscBT otable; /* mark indices of other processors' is[] */
176: PetscInt bs = C->rmap->bs, Bn = c->B->cmap->n, Bnbs = Bn / bs, *Bowners;
177: IS garray_local, garray_gl;
179: PetscFunctionBegin;
180: PetscCall(PetscObjectGetComm((PetscObject)C, &comm));
181: size = c->size;
182: rank = c->rank;
183: Mbs = c->Mbs;
185: PetscCall(PetscObjectGetNewTag((PetscObject)C, &tag1));
186: PetscCall(PetscObjectGetNewTag((PetscObject)C, &tag2));
188: /* create tables used in
189: step 1: table[i] - mark c->garray of proc [i]
190: step 3: table[i] - mark indices of is[i] when whose=MINE
191: table[0] - mark incideces of is[] when whose=OTHER */
192: len = PetscMax(is_max, size);
193: PetscCall(PetscMalloc2(len, &table, (Mbs / PETSC_BITS_PER_BYTE + 1) * len, &t_p));
194: for (i = 0; i < len; i++) table[i] = t_p + (Mbs / PETSC_BITS_PER_BYTE + 1) * i;
196: PetscCall(MPIU_Allreduce(&is_max, &ois_max, 1, MPIU_INT, MPI_MAX, comm));
198: /* 1. Send this processor's is[] to other processors */
199: /* allocate spaces */
200: PetscCall(PetscMalloc1(is_max, &n));
201: len = 0;
202: for (i = 0; i < is_max; i++) {
203: PetscCall(ISGetLocalSize(is[i], &n[i]));
204: len += n[i];
205: }
206: if (!len) {
207: is_max = 0;
208: } else {
209: len += 1 + is_max; /* max length of data1 for one processor */
210: }
212: PetscCall(PetscMalloc1(size * len + 1, &data1));
213: PetscCall(PetscMalloc1(size, &data1_start));
214: for (i = 0; i < size; i++) data1_start[i] = data1 + i * len;
216: PetscCall(PetscMalloc4(size, &len_s, size, &btable, size, &iwork, size + 1, &Bowners));
218: /* gather c->garray from all processors */
219: PetscCall(ISCreateGeneral(comm, Bnbs, c->garray, PETSC_COPY_VALUES, &garray_local));
220: PetscCall(ISAllGather(garray_local, &garray_gl));
221: PetscCall(ISDestroy(&garray_local));
222: PetscCallMPI(MPI_Allgather(&Bnbs, 1, MPIU_INT, Bowners + 1, 1, MPIU_INT, comm));
224: Bowners[0] = 0;
225: for (i = 0; i < size; i++) Bowners[i + 1] += Bowners[i];
227: if (is_max) {
228: /* hash table ctable which maps c->row to proc_id) */
229: PetscCall(PetscMalloc1(Mbs, &ctable));
230: for (proc_id = 0, j = 0; proc_id < size; proc_id++) {
231: for (; j < C->rmap->range[proc_id + 1] / bs; j++) ctable[j] = proc_id;
232: }
234: /* hash tables marking c->garray */
235: PetscCall(ISGetIndices(garray_gl, &idx_i));
236: for (i = 0; i < size; i++) {
237: table_i = table[i];
238: PetscCall(PetscBTMemzero(Mbs, table_i));
239: for (j = Bowners[i]; j < Bowners[i + 1]; j++) { /* go through B cols of proc[i]*/
240: PetscCall(PetscBTSet(table_i, idx_i[j]));
241: }
242: }
243: PetscCall(ISRestoreIndices(garray_gl, &idx_i));
244: } /* if (is_max) */
245: PetscCall(ISDestroy(&garray_gl));
247: /* evaluate communication - mesg to who, length, and buffer space */
248: for (i = 0; i < size; i++) len_s[i] = 0;
250: /* header of data1 */
251: for (proc_id = 0; proc_id < size; proc_id++) {
252: iwork[proc_id] = 0;
253: *data1_start[proc_id] = is_max;
254: data1_start[proc_id]++;
255: for (j = 0; j < is_max; j++) {
256: if (proc_id == rank) {
257: *data1_start[proc_id] = n[j];
258: } else {
259: *data1_start[proc_id] = 0;
260: }
261: data1_start[proc_id]++;
262: }
263: }
265: for (i = 0; i < is_max; i++) {
266: PetscCall(ISGetIndices(is[i], &idx_i));
267: for (j = 0; j < n[i]; j++) {
268: idx = idx_i[j];
269: *data1_start[rank] = idx;
270: data1_start[rank]++; /* for local processing */
271: proc_end = ctable[idx];
272: for (proc_id = 0; proc_id <= proc_end; proc_id++) { /* for others to process */
273: if (proc_id == rank) continue; /* done before this loop */
274: if (proc_id < proc_end && !PetscBTLookup(table[proc_id], idx)) continue; /* no need for sending idx to [proc_id] */
275: *data1_start[proc_id] = idx;
276: data1_start[proc_id]++;
277: len_s[proc_id]++;
278: }
279: }
280: /* update header data */
281: for (proc_id = 0; proc_id < size; proc_id++) {
282: if (proc_id == rank) continue;
283: *(data1 + proc_id * len + 1 + i) = len_s[proc_id] - iwork[proc_id];
284: iwork[proc_id] = len_s[proc_id];
285: }
286: PetscCall(ISRestoreIndices(is[i], &idx_i));
287: }
289: nrqs = 0;
290: nrqr = 0;
291: for (i = 0; i < size; i++) {
292: data1_start[i] = data1 + i * len;
293: if (len_s[i]) {
294: nrqs++;
295: len_s[i] += 1 + is_max; /* add no. of header msg */
296: }
297: }
299: for (i = 0; i < is_max; i++) PetscCall(ISDestroy(&is[i]));
300: PetscCall(PetscFree(n));
301: PetscCall(PetscFree(ctable));
303: /* Determine the number of messages to expect, their lengths, from from-ids */
304: PetscCall(PetscGatherNumberOfMessages(comm, NULL, len_s, &nrqr));
305: PetscCall(PetscGatherMessageLengths(comm, nrqs, nrqr, len_s, &id_r1, &len_r1));
307: /* Now post the sends */
308: PetscCall(PetscMalloc2(size, &s_waits1, size, &s_waits2));
309: k = 0;
310: for (proc_id = 0; proc_id < size; proc_id++) { /* send data1 to processor [proc_id] */
311: if (len_s[proc_id]) {
312: PetscCallMPI(MPI_Isend(data1_start[proc_id], len_s[proc_id], MPIU_INT, proc_id, tag1, comm, s_waits1 + k));
313: k++;
314: }
315: }
317: /* 2. Receive other's is[] and process. Then send back */
318: len = 0;
319: for (i = 0; i < nrqr; i++) {
320: if (len_r1[i] > len) len = len_r1[i];
321: }
322: PetscCall(PetscFree(len_r1));
323: PetscCall(PetscFree(id_r1));
325: for (proc_id = 0; proc_id < size; proc_id++) len_s[proc_id] = iwork[proc_id] = 0;
327: PetscCall(PetscMalloc1(len + 1, &odata1));
328: PetscCall(PetscMalloc1(size, &odata2_ptr));
329: PetscCall(PetscBTCreate(Mbs, &otable));
331: len_max = ois_max * (Mbs + 1); /* max space storing all is[] for each receive */
332: len_est = 2 * len_max; /* estimated space of storing is[] for all receiving messages */
333: PetscCall(PetscMalloc1(len_est + 1, &odata2));
334: nodata2 = 0; /* nodata2+1: num of PetscMalloc(,&odata2_ptr[]) called */
336: odata2_ptr[nodata2] = odata2;
338: len_unused = len_est; /* unused space in the array odata2_ptr[nodata2]-- needs to be >= len_max */
340: k = 0;
341: while (k < nrqr) {
342: /* Receive messages */
343: PetscCallMPI(MPI_Iprobe(MPI_ANY_SOURCE, tag1, comm, &flag, &r_status));
344: if (flag) {
345: PetscCallMPI(MPI_Get_count(&r_status, MPIU_INT, &len));
346: proc_id = r_status.MPI_SOURCE;
347: PetscCallMPI(MPI_Irecv(odata1, len, MPIU_INT, proc_id, r_status.MPI_TAG, comm, &r_req));
348: PetscCallMPI(MPI_Wait(&r_req, &r_status));
350: /* Process messages */
351: /* make sure there is enough unused space in odata2 array */
352: if (len_unused < len_max) { /* allocate more space for odata2 */
353: PetscCall(PetscMalloc1(len_est + 1, &odata2));
355: odata2_ptr[++nodata2] = odata2;
357: len_unused = len_est;
358: }
360: PetscCall(MatIncreaseOverlap_MPISBAIJ_Local(C, odata1, OTHER, odata2, &otable));
361: len = 1 + odata2[0];
362: for (i = 0; i < odata2[0]; i++) len += odata2[1 + i];
364: /* Send messages back */
365: PetscCallMPI(MPI_Isend(odata2, len, MPIU_INT, proc_id, tag2, comm, s_waits2 + k));
366: k++;
367: odata2 += len;
368: len_unused -= len;
369: len_s[proc_id] = len; /* num of messages sending back to [proc_id] by this proc */
370: }
371: }
372: PetscCall(PetscFree(odata1));
373: PetscCall(PetscBTDestroy(&otable));
375: /* 3. Do local work on this processor's is[] */
376: /* make sure there is enough unused space in odata2(=data) array */
377: len_max = is_max * (Mbs + 1); /* max space storing all is[] for this processor */
378: if (len_unused < len_max) { /* allocate more space for odata2 */
379: PetscCall(PetscMalloc1(len_est + 1, &odata2));
381: odata2_ptr[++nodata2] = odata2;
382: }
384: data = odata2;
385: PetscCall(MatIncreaseOverlap_MPISBAIJ_Local(C, data1_start[rank], MINE, data, table));
386: PetscCall(PetscFree(data1_start));
388: /* 4. Receive work done on other processors, then merge */
389: /* get max number of messages that this processor expects to recv */
390: PetscCall(MPIU_Allreduce(len_s, iwork, size, MPI_INT, MPI_MAX, comm));
391: PetscCall(PetscMalloc1(iwork[rank] + 1, &data2));
392: PetscCall(PetscFree4(len_s, btable, iwork, Bowners));
394: k = 0;
395: while (k < nrqs) {
396: /* Receive messages */
397: PetscCallMPI(MPI_Iprobe(MPI_ANY_SOURCE, tag2, comm, &flag, &r_status));
398: if (flag) {
399: PetscCallMPI(MPI_Get_count(&r_status, MPIU_INT, &len));
401: proc_id = r_status.MPI_SOURCE;
403: PetscCallMPI(MPI_Irecv(data2, len, MPIU_INT, proc_id, r_status.MPI_TAG, comm, &r_req));
404: PetscCallMPI(MPI_Wait(&r_req, &r_status));
405: if (len > 1 + is_max) { /* Add data2 into data */
406: data2_i = data2 + 1 + is_max;
407: for (i = 0; i < is_max; i++) {
408: table_i = table[i];
409: data_i = data + 1 + is_max + Mbs * i;
410: isz = data[1 + i];
411: for (j = 0; j < data2[1 + i]; j++) {
412: col = data2_i[j];
413: if (!PetscBTLookupSet(table_i, col)) data_i[isz++] = col;
414: }
415: data[1 + i] = isz;
416: if (i < is_max - 1) data2_i += data2[1 + i];
417: }
418: }
419: k++;
420: }
421: }
422: PetscCall(PetscFree(data2));
423: PetscCall(PetscFree2(table, t_p));
425: /* phase 1 sends are complete */
426: PetscCall(PetscMalloc1(size, &s_status));
427: if (nrqs) PetscCallMPI(MPI_Waitall(nrqs, s_waits1, s_status));
428: PetscCall(PetscFree(data1));
430: /* phase 2 sends are complete */
431: if (nrqr) PetscCallMPI(MPI_Waitall(nrqr, s_waits2, s_status));
432: PetscCall(PetscFree2(s_waits1, s_waits2));
433: PetscCall(PetscFree(s_status));
435: /* 5. Create new is[] */
436: for (i = 0; i < is_max; i++) {
437: data_i = data + 1 + is_max + Mbs * i;
438: PetscCall(ISCreateGeneral(PETSC_COMM_SELF, data[1 + i], data_i, PETSC_COPY_VALUES, is + i));
439: }
440: for (k = 0; k <= nodata2; k++) PetscCall(PetscFree(odata2_ptr[k]));
441: PetscCall(PetscFree(odata2_ptr));
442: PetscFunctionReturn(PETSC_SUCCESS);
443: }
445: /*
446: MatIncreaseOverlap_MPISBAIJ_Local - Called by MatIncreaseOverlap, to do
447: the work on the local processor.
449: Inputs:
450: C - MAT_MPISBAIJ;
451: data - holds is[]. See MatIncreaseOverlap_MPISBAIJ_Once() for the format.
452: whose - whose is[] to be processed,
453: MINE: this processor's is[]
454: OTHER: other processor's is[]
455: Output:
456: nidx - whose = MINE:
457: holds input and newly found indices in the same format as data
458: whose = OTHER:
459: only holds the newly found indices
460: table - table[i]: mark the indices of is[i], i=0,...,is_max. Used only in the case 'whose=MINE'.
461: */
462: /* Would computation be reduced by swapping the loop 'for each is' and 'for each row'? */
463: static PetscErrorCode MatIncreaseOverlap_MPISBAIJ_Local(Mat C, PetscInt *data, PetscInt whose, PetscInt *nidx, PetscBT *table)
464: {
465: Mat_MPISBAIJ *c = (Mat_MPISBAIJ *)C->data;
466: Mat_SeqSBAIJ *a = (Mat_SeqSBAIJ *)c->A->data;
467: Mat_SeqBAIJ *b = (Mat_SeqBAIJ *)c->B->data;
468: PetscInt row, mbs, Mbs, *nidx_i, col, col_max, isz, isz0, *ai, *aj, *bi, *bj, *garray, rstart, l;
469: PetscInt a_start, a_end, b_start, b_end, i, j, k, is_max, *idx_i, n;
470: PetscBT table0; /* mark the indices of input is[] for look up */
471: PetscBT table_i; /* points to i-th table. When whose=OTHER, a single table is used for all is[] */
473: PetscFunctionBegin;
474: Mbs = c->Mbs;
475: mbs = a->mbs;
476: ai = a->i;
477: aj = a->j;
478: bi = b->i;
479: bj = b->j;
480: garray = c->garray;
481: rstart = c->rstartbs;
482: is_max = data[0];
484: PetscCall(PetscBTCreate(Mbs, &table0));
486: nidx[0] = is_max;
487: idx_i = data + is_max + 1; /* ptr to input is[0] array */
488: nidx_i = nidx + is_max + 1; /* ptr to output is[0] array */
489: for (i = 0; i < is_max; i++) { /* for each is */
490: isz = 0;
491: n = data[1 + i]; /* size of input is[i] */
493: /* initialize and set table_i(mark idx and nidx) and table0(only mark idx) */
494: if (whose == MINE) { /* process this processor's is[] */
495: table_i = table[i];
496: nidx_i = nidx + 1 + is_max + Mbs * i;
497: } else { /* process other processor's is[] - only use one temp table */
498: table_i = table[0];
499: }
500: PetscCall(PetscBTMemzero(Mbs, table_i));
501: PetscCall(PetscBTMemzero(Mbs, table0));
502: if (n == 0) {
503: nidx[1 + i] = 0; /* size of new is[i] */
504: continue;
505: }
507: isz0 = 0;
508: col_max = 0;
509: for (j = 0; j < n; j++) {
510: col = idx_i[j];
511: PetscCheck(col < Mbs, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "index col %" PetscInt_FMT " >= Mbs %" PetscInt_FMT, col, Mbs);
512: if (!PetscBTLookupSet(table_i, col)) {
513: PetscCall(PetscBTSet(table0, col));
514: if (whose == MINE) nidx_i[isz0] = col;
515: if (col_max < col) col_max = col;
516: isz0++;
517: }
518: }
520: if (whose == MINE) isz = isz0;
521: k = 0; /* no. of indices from input is[i] that have been examined */
522: for (row = 0; row < mbs; row++) {
523: a_start = ai[row];
524: a_end = ai[row + 1];
525: b_start = bi[row];
526: b_end = bi[row + 1];
527: if (PetscBTLookup(table0, row + rstart)) { /* row is on input is[i]:
528: do row search: collect all col in this row */
529: for (l = a_start; l < a_end; l++) { /* Amat */
530: col = aj[l] + rstart;
531: if (!PetscBTLookupSet(table_i, col)) nidx_i[isz++] = col;
532: }
533: for (l = b_start; l < b_end; l++) { /* Bmat */
534: col = garray[bj[l]];
535: if (!PetscBTLookupSet(table_i, col)) nidx_i[isz++] = col;
536: }
537: k++;
538: if (k >= isz0) break; /* for (row=0; row<mbs; row++) */
539: } else { /* row is not on input is[i]:
540: do col search: add row onto nidx_i if there is a col in nidx_i */
541: for (l = a_start; l < a_end; l++) { /* Amat */
542: col = aj[l] + rstart;
543: if (col > col_max) break;
544: if (PetscBTLookup(table0, col)) {
545: if (!PetscBTLookupSet(table_i, row + rstart)) nidx_i[isz++] = row + rstart;
546: break; /* for l = start; l<end ; l++) */
547: }
548: }
549: for (l = b_start; l < b_end; l++) { /* Bmat */
550: col = garray[bj[l]];
551: if (col > col_max) break;
552: if (PetscBTLookup(table0, col)) {
553: if (!PetscBTLookupSet(table_i, row + rstart)) nidx_i[isz++] = row + rstart;
554: break; /* for l = start; l<end ; l++) */
555: }
556: }
557: }
558: }
560: if (i < is_max - 1) {
561: idx_i += n; /* ptr to input is[i+1] array */
562: nidx_i += isz; /* ptr to output is[i+1] array */
563: }
564: nidx[1 + i] = isz; /* size of new is[i] */
565: } /* for each is */
566: PetscCall(PetscBTDestroy(&table0));
567: PetscFunctionReturn(PETSC_SUCCESS);
568: }