Actual source code: jp.c

  1: #include <../src/mat/impls/aij/mpi/mpiaij.h>
  2: #include <petscsf.h>

  4: typedef struct {
  5:   PetscSF    sf;
  6:   PetscReal *dwts, *owts;
  7:   PetscInt  *dmask, *omask, *cmask;
  8:   PetscBool  local;
  9: } MC_JP;

 11: static PetscErrorCode MatColoringDestroy_JP(MatColoring mc)
 12: {
 13:   PetscFunctionBegin;
 14:   PetscCall(PetscFree(mc->data));
 15:   PetscFunctionReturn(PETSC_SUCCESS);
 16: }

 18: static PetscErrorCode MatColoringSetFromOptions_JP(MatColoring mc, PetscOptionItems *PetscOptionsObject)
 19: {
 20:   MC_JP *jp = (MC_JP *)mc->data;

 22:   PetscFunctionBegin;
 23:   PetscOptionsHeadBegin(PetscOptionsObject, "JP options");
 24:   PetscCall(PetscOptionsBool("-mat_coloring_jp_local", "Do an initial coloring of local columns", "", jp->local, &jp->local, NULL));
 25:   PetscOptionsHeadEnd();
 26:   PetscFunctionReturn(PETSC_SUCCESS);
 27: }

 29: static PetscErrorCode MCJPGreatestWeight_Private(MatColoring mc, const PetscReal *weights, PetscReal *maxweights)
 30: {
 31:   MC_JP          *jp = (MC_JP *)mc->data;
 32:   Mat             G  = mc->mat, dG, oG;
 33:   PetscBool       isSeq, isMPI;
 34:   Mat_MPIAIJ     *aij;
 35:   Mat_SeqAIJ     *daij, *oaij;
 36:   PetscInt       *di, *oi, *dj, *oj;
 37:   PetscSF         sf = jp->sf;
 38:   PetscLayout     layout;
 39:   PetscInt        dn, on;
 40:   PetscInt        i, j, l;
 41:   PetscReal      *dwts = jp->dwts, *owts = jp->owts;
 42:   PetscInt        ncols;
 43:   const PetscInt *cols;

 45:   PetscFunctionBegin;
 46:   PetscCall(PetscObjectTypeCompare((PetscObject)G, MATSEQAIJ, &isSeq));
 47:   PetscCall(PetscObjectTypeCompare((PetscObject)G, MATMPIAIJ, &isMPI));
 48:   PetscCheck(isSeq || isMPI, PetscObjectComm((PetscObject)G), PETSC_ERR_ARG_WRONGSTATE, "MatColoringDegrees requires an MPI/SEQAIJ Matrix");

 50:   /* get the inner matrix structure */
 51:   oG = NULL;
 52:   oi = NULL;
 53:   oj = NULL;
 54:   if (isMPI) {
 55:     aij  = (Mat_MPIAIJ *)G->data;
 56:     dG   = aij->A;
 57:     oG   = aij->B;
 58:     daij = (Mat_SeqAIJ *)dG->data;
 59:     oaij = (Mat_SeqAIJ *)oG->data;
 60:     di   = daij->i;
 61:     dj   = daij->j;
 62:     oi   = oaij->i;
 63:     oj   = oaij->j;
 64:     PetscCall(MatGetSize(oG, &dn, &on));
 65:     if (!sf) {
 66:       PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)mc), &sf));
 67:       PetscCall(MatGetLayouts(G, &layout, NULL));
 68:       PetscCall(PetscSFSetGraphLayout(sf, layout, on, NULL, PETSC_COPY_VALUES, aij->garray));
 69:       jp->sf = sf;
 70:     }
 71:   } else {
 72:     dG = G;
 73:     PetscCall(MatGetSize(dG, NULL, &dn));
 74:     daij = (Mat_SeqAIJ *)dG->data;
 75:     di   = daij->i;
 76:     dj   = daij->j;
 77:   }
 78:   /* set up the distance-zero weights */
 79:   if (!dwts) {
 80:     PetscCall(PetscMalloc1(dn, &dwts));
 81:     jp->dwts = dwts;
 82:     if (oG) {
 83:       PetscCall(PetscMalloc1(on, &owts));
 84:       jp->owts = owts;
 85:     }
 86:   }
 87:   for (i = 0; i < dn; i++) {
 88:     maxweights[i] = weights[i];
 89:     dwts[i]       = maxweights[i];
 90:   }
 91:   /* get the off-diagonal weights */
 92:   if (oG) {
 93:     PetscCall(PetscLogEventBegin(MATCOLORING_Comm, mc, 0, 0, 0));
 94:     PetscCall(PetscSFBcastBegin(sf, MPIU_REAL, dwts, owts, MPI_REPLACE));
 95:     PetscCall(PetscSFBcastEnd(sf, MPIU_REAL, dwts, owts, MPI_REPLACE));
 96:     PetscCall(PetscLogEventEnd(MATCOLORING_Comm, mc, 0, 0, 0));
 97:   }
 98:   /* check for the maximum out to the distance of the coloring */
 99:   for (l = 0; l < mc->dist; l++) {
100:     /* check for on-diagonal greater weights */
101:     for (i = 0; i < dn; i++) {
102:       ncols = di[i + 1] - di[i];
103:       cols  = &(dj[di[i]]);
104:       for (j = 0; j < ncols; j++) {
105:         if (dwts[cols[j]] > maxweights[i]) maxweights[i] = dwts[cols[j]];
106:       }
107:       /* check for off-diagonal greater weights */
108:       if (oG) {
109:         ncols = oi[i + 1] - oi[i];
110:         cols  = &(oj[oi[i]]);
111:         for (j = 0; j < ncols; j++) {
112:           if (owts[cols[j]] > maxweights[i]) maxweights[i] = owts[cols[j]];
113:         }
114:       }
115:     }
116:     if (l < mc->dist - 1) {
117:       for (i = 0; i < dn; i++) dwts[i] = maxweights[i];
118:       if (oG) {
119:         PetscCall(PetscLogEventBegin(MATCOLORING_Comm, mc, 0, 0, 0));
120:         PetscCall(PetscSFBcastBegin(sf, MPIU_REAL, dwts, owts, MPI_REPLACE));
121:         PetscCall(PetscSFBcastEnd(sf, MPIU_REAL, dwts, owts, MPI_REPLACE));
122:         PetscCall(PetscLogEventEnd(MATCOLORING_Comm, mc, 0, 0, 0));
123:       }
124:     }
125:   }
126:   PetscFunctionReturn(PETSC_SUCCESS);
127: }

129: static PetscErrorCode MCJPInitialLocalColor_Private(MatColoring mc, PetscInt *lperm, ISColoringValue *colors)
130: {
131:   PetscInt        j, i, s, e, n, bidx, cidx, idx, dist, distance = mc->dist;
132:   Mat             G = mc->mat, dG, oG;
133:   PetscInt       *seen;
134:   PetscInt       *idxbuf;
135:   PetscBool      *boundary;
136:   PetscInt       *distbuf;
137:   PetscInt       *colormask;
138:   PetscInt        ncols;
139:   const PetscInt *cols;
140:   PetscBool       isSeq, isMPI;
141:   Mat_MPIAIJ     *aij;
142:   Mat_SeqAIJ     *daij, *oaij;
143:   PetscInt       *di, *dj, dn;
144:   PetscInt       *oi;

146:   PetscFunctionBegin;
147:   PetscCall(PetscLogEventBegin(MATCOLORING_Local, mc, 0, 0, 0));
148:   PetscCall(MatGetOwnershipRange(G, &s, &e));
149:   n = e - s;
150:   PetscCall(PetscObjectBaseTypeCompare((PetscObject)G, MATSEQAIJ, &isSeq));
151:   PetscCall(PetscObjectTypeCompare((PetscObject)G, MATMPIAIJ, &isMPI));
152:   PetscCheck(isSeq || isMPI, PetscObjectComm((PetscObject)G), PETSC_ERR_ARG_WRONGSTATE, "MatColoringDegrees requires an MPI/SEQAIJ Matrix");

154:   /* get the inner matrix structure */
155:   oG = NULL;
156:   oi = NULL;
157:   if (isMPI) {
158:     aij  = (Mat_MPIAIJ *)G->data;
159:     dG   = aij->A;
160:     oG   = aij->B;
161:     daij = (Mat_SeqAIJ *)dG->data;
162:     oaij = (Mat_SeqAIJ *)oG->data;
163:     di   = daij->i;
164:     dj   = daij->j;
165:     oi   = oaij->i;
166:     PetscCall(MatGetSize(oG, &dn, NULL));
167:   } else {
168:     dG = G;
169:     PetscCall(MatGetSize(dG, NULL, &dn));
170:     daij = (Mat_SeqAIJ *)dG->data;
171:     di   = daij->i;
172:     dj   = daij->j;
173:   }
174:   PetscCall(PetscMalloc5(n, &colormask, n, &seen, n, &idxbuf, n, &distbuf, n, &boundary));
175:   for (i = 0; i < dn; i++) {
176:     seen[i]      = -1;
177:     colormask[i] = -1;
178:     boundary[i]  = PETSC_FALSE;
179:   }
180:   /* pass one -- figure out which ones are off-boundary in the distance-n sense */
181:   if (oG) {
182:     for (i = 0; i < dn; i++) {
183:       bidx = -1;
184:       /* nonempty off-diagonal, so this one is on the boundary */
185:       if (oi[i] != oi[i + 1]) {
186:         boundary[i] = PETSC_TRUE;
187:         continue;
188:       }
189:       ncols = di[i + 1] - di[i];
190:       cols  = &(dj[di[i]]);
191:       for (j = 0; j < ncols; j++) {
192:         bidx++;
193:         seen[cols[j]] = i;
194:         distbuf[bidx] = 1;
195:         idxbuf[bidx]  = cols[j];
196:       }
197:       while (bidx >= 0) {
198:         idx  = idxbuf[bidx];
199:         dist = distbuf[bidx];
200:         bidx--;
201:         if (dist < distance) {
202:           if (oi[idx + 1] != oi[idx]) {
203:             boundary[i] = PETSC_TRUE;
204:             break;
205:           }
206:           ncols = di[idx + 1] - di[idx];
207:           cols  = &(dj[di[idx]]);
208:           for (j = 0; j < ncols; j++) {
209:             if (seen[cols[j]] != i) {
210:               bidx++;
211:               seen[cols[j]] = i;
212:               idxbuf[bidx]  = cols[j];
213:               distbuf[bidx] = dist + 1;
214:             }
215:           }
216:         }
217:       }
218:     }
219:     for (i = 0; i < dn; i++) seen[i] = -1;
220:   }
221:   /* pass two -- color it by looking at nearby vertices and building a mask */
222:   for (i = 0; i < dn; i++) {
223:     cidx = lperm[i];
224:     if (!boundary[cidx]) {
225:       bidx  = -1;
226:       ncols = di[cidx + 1] - di[cidx];
227:       cols  = &(dj[di[cidx]]);
228:       for (j = 0; j < ncols; j++) {
229:         bidx++;
230:         seen[cols[j]] = cidx;
231:         distbuf[bidx] = 1;
232:         idxbuf[bidx]  = cols[j];
233:       }
234:       while (bidx >= 0) {
235:         idx  = idxbuf[bidx];
236:         dist = distbuf[bidx];
237:         bidx--;
238:         /* mask this color */
239:         if (colors[idx] < IS_COLORING_MAX) colormask[colors[idx]] = cidx;
240:         if (dist < distance) {
241:           ncols = di[idx + 1] - di[idx];
242:           cols  = &(dj[di[idx]]);
243:           for (j = 0; j < ncols; j++) {
244:             if (seen[cols[j]] != cidx) {
245:               bidx++;
246:               seen[cols[j]] = cidx;
247:               idxbuf[bidx]  = cols[j];
248:               distbuf[bidx] = dist + 1;
249:             }
250:           }
251:         }
252:       }
253:       /* find the lowest untaken color */
254:       for (j = 0; j < n; j++) {
255:         if (colormask[j] != cidx || j >= mc->maxcolors) {
256:           PetscCall(ISColoringValueCast(j, &colors[cidx]));
257:           break;
258:         }
259:       }
260:     }
261:   }
262:   PetscCall(PetscFree5(colormask, seen, idxbuf, distbuf, boundary));
263:   PetscCall(PetscLogEventEnd(MATCOLORING_Local, mc, 0, 0, 0));
264:   PetscFunctionReturn(PETSC_SUCCESS);
265: }

267: static PetscErrorCode MCJPMinColor_Private(MatColoring mc, ISColoringValue maxcolor, const ISColoringValue *colors, ISColoringValue *mincolors)
268: {
269:   MC_JP          *jp = (MC_JP *)mc->data;
270:   Mat             G  = mc->mat, dG, oG;
271:   PetscBool       isSeq, isMPI;
272:   Mat_MPIAIJ     *aij;
273:   Mat_SeqAIJ     *daij, *oaij;
274:   PetscInt       *di, *oi, *dj, *oj;
275:   PetscSF         sf = jp->sf;
276:   PetscLayout     layout;
277:   PetscInt        maskrounds, maskbase, maskradix;
278:   PetscInt        dn, on;
279:   PetscInt        i, j, l, k;
280:   PetscInt       *dmask = jp->dmask, *omask = jp->omask, *cmask = jp->cmask, curmask;
281:   PetscInt        ncols;
282:   const PetscInt *cols;

284:   PetscFunctionBegin;
285:   maskradix  = sizeof(PetscInt) * 8;
286:   maskrounds = 1 + maxcolor / (maskradix);
287:   maskbase   = 0;
288:   PetscCall(PetscObjectBaseTypeCompare((PetscObject)G, MATSEQAIJ, &isSeq));
289:   PetscCall(PetscObjectTypeCompare((PetscObject)G, MATMPIAIJ, &isMPI));
290:   PetscCheck(isSeq || isMPI, PetscObjectComm((PetscObject)G), PETSC_ERR_ARG_WRONGSTATE, "MatColoringDegrees requires an MPI/SEQAIJ Matrix");

292:   /* get the inner matrix structure */
293:   oG = NULL;
294:   oi = NULL;
295:   oj = NULL;
296:   if (isMPI) {
297:     aij  = (Mat_MPIAIJ *)G->data;
298:     dG   = aij->A;
299:     oG   = aij->B;
300:     daij = (Mat_SeqAIJ *)dG->data;
301:     oaij = (Mat_SeqAIJ *)oG->data;
302:     di   = daij->i;
303:     dj   = daij->j;
304:     oi   = oaij->i;
305:     oj   = oaij->j;
306:     PetscCall(MatGetSize(oG, &dn, &on));
307:     if (!sf) {
308:       PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)mc), &sf));
309:       PetscCall(MatGetLayouts(G, &layout, NULL));
310:       PetscCall(PetscSFSetGraphLayout(sf, layout, on, NULL, PETSC_COPY_VALUES, aij->garray));
311:       jp->sf = sf;
312:     }
313:   } else {
314:     dG = G;
315:     PetscCall(MatGetSize(dG, NULL, &dn));
316:     daij = (Mat_SeqAIJ *)dG->data;
317:     di   = daij->i;
318:     dj   = daij->j;
319:   }
320:   for (i = 0; i < dn; i++) mincolors[i] = IS_COLORING_MAX;
321:   /* set up the distance-zero mask */
322:   if (!dmask) {
323:     PetscCall(PetscMalloc1(dn, &dmask));
324:     PetscCall(PetscMalloc1(dn, &cmask));
325:     jp->cmask = cmask;
326:     jp->dmask = dmask;
327:     if (oG) {
328:       PetscCall(PetscMalloc1(on, &omask));
329:       jp->omask = omask;
330:     }
331:   }
332:   /* the number of colors may be more than the number of bits in a PetscInt; take multiple rounds */
333:   for (k = 0; k < maskrounds; k++) {
334:     for (i = 0; i < dn; i++) {
335:       cmask[i] = 0;
336:       if (colors[i] < maskbase + maskradix && colors[i] >= maskbase) cmask[i] = 1 << (colors[i] - maskbase);
337:       dmask[i] = cmask[i];
338:     }
339:     if (oG) {
340:       PetscCall(PetscLogEventBegin(MATCOLORING_Comm, mc, 0, 0, 0));
341:       PetscCall(PetscSFBcastBegin(sf, MPIU_INT, dmask, omask, MPI_REPLACE));
342:       PetscCall(PetscSFBcastEnd(sf, MPIU_INT, dmask, omask, MPI_REPLACE));
343:       PetscCall(PetscLogEventEnd(MATCOLORING_Comm, mc, 0, 0, 0));
344:     }
345:     /* fill in the mask out to the distance of the coloring */
346:     for (l = 0; l < mc->dist; l++) {
347:       /* fill in the on-and-off diagonal mask */
348:       for (i = 0; i < dn; i++) {
349:         ncols = di[i + 1] - di[i];
350:         cols  = &(dj[di[i]]);
351:         for (j = 0; j < ncols; j++) cmask[i] = cmask[i] | dmask[cols[j]];
352:         if (oG) {
353:           ncols = oi[i + 1] - oi[i];
354:           cols  = &(oj[oi[i]]);
355:           for (j = 0; j < ncols; j++) cmask[i] = cmask[i] | omask[cols[j]];
356:         }
357:       }
358:       for (i = 0; i < dn; i++) dmask[i] = cmask[i];
359:       if (l < mc->dist - 1) {
360:         if (oG) {
361:           PetscCall(PetscLogEventBegin(MATCOLORING_Comm, mc, 0, 0, 0));
362:           PetscCall(PetscSFBcastBegin(sf, MPIU_INT, dmask, omask, MPI_REPLACE));
363:           PetscCall(PetscSFBcastEnd(sf, MPIU_INT, dmask, omask, MPI_REPLACE));
364:           PetscCall(PetscLogEventEnd(MATCOLORING_Comm, mc, 0, 0, 0));
365:         }
366:       }
367:     }
368:     /* read through the mask to see if we've discovered an acceptable color for any vertices in this round */
369:     for (i = 0; i < dn; i++) {
370:       if (mincolors[i] == IS_COLORING_MAX) {
371:         curmask = dmask[i];
372:         for (j = 0; j < maskradix; j++) {
373:           if (curmask % 2 == 0) {
374:             PetscCall(ISColoringValueCast(j + maskbase, &mincolors[i]));
375:             break;
376:           }
377:           curmask = curmask >> 1;
378:         }
379:       }
380:     }
381:     /* do the next maskradix colors */
382:     maskbase += maskradix;
383:   }
384:   for (i = 0; i < dn; i++) {
385:     if (mincolors[i] == IS_COLORING_MAX) mincolors[i] = maxcolor + 1;
386:   }
387:   PetscFunctionReturn(PETSC_SUCCESS);
388: }

390: static PetscErrorCode MatColoringApply_JP(MatColoring mc, ISColoring *iscoloring)
391: {
392:   MC_JP           *jp = (MC_JP *)mc->data;
393:   PetscInt         i, nadded, nadded_total, nadded_total_old, ntotal, n;
394:   PetscInt         maxcolor_local = 0, maxcolor_global = 0, *lperm;
395:   PetscMPIInt      rank;
396:   PetscReal       *weights, *maxweights;
397:   ISColoringValue *color, *mincolor;

399:   PetscFunctionBegin;
400:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)mc), &rank));
401:   PetscCall(PetscLogEventBegin(MATCOLORING_Weights, mc, 0, 0, 0));
402:   PetscCall(MatColoringCreateWeights(mc, &weights, &lperm));
403:   PetscCall(PetscLogEventEnd(MATCOLORING_Weights, mc, 0, 0, 0));
404:   PetscCall(MatGetSize(mc->mat, NULL, &ntotal));
405:   PetscCall(MatGetLocalSize(mc->mat, NULL, &n));
406:   PetscCall(PetscMalloc1(n, &maxweights));
407:   PetscCall(PetscMalloc1(n, &color));
408:   PetscCall(PetscMalloc1(n, &mincolor));
409:   for (i = 0; i < n; i++) {
410:     color[i]    = IS_COLORING_MAX;
411:     mincolor[i] = 0;
412:   }
413:   nadded           = 0;
414:   nadded_total     = 0;
415:   nadded_total_old = 0;
416:   /* compute purely local vertices */
417:   if (jp->local) {
418:     PetscCall(MCJPInitialLocalColor_Private(mc, lperm, color));
419:     for (i = 0; i < n; i++) {
420:       if (color[i] < IS_COLORING_MAX) {
421:         nadded++;
422:         weights[i] = -1;
423:         if (color[i] > maxcolor_local) maxcolor_local = color[i];
424:       }
425:     }
426:     PetscCallMPI(MPIU_Allreduce(&nadded, &nadded_total, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)mc)));
427:     PetscCallMPI(MPIU_Allreduce(&maxcolor_local, &maxcolor_global, 1, MPIU_INT, MPI_MAX, PetscObjectComm((PetscObject)mc)));
428:   }
429:   while (nadded_total < ntotal) {
430:     PetscCall(MCJPMinColor_Private(mc, (ISColoringValue)maxcolor_global, color, mincolor));
431:     PetscCall(MCJPGreatestWeight_Private(mc, weights, maxweights));
432:     for (i = 0; i < n; i++) {
433:       /* choose locally maximal vertices; weights less than zero are omitted from the graph */
434:       if (weights[i] >= maxweights[i] && weights[i] >= 0.) {
435:         /* assign the minimum possible color */
436:         if (mc->maxcolors > mincolor[i]) {
437:           color[i] = mincolor[i];
438:         } else {
439:           color[i] = (ISColoringValue)mc->maxcolors;
440:         }
441:         if (color[i] > maxcolor_local) maxcolor_local = color[i];
442:         weights[i] = -1.;
443:         nadded++;
444:       }
445:     }
446:     PetscCallMPI(MPIU_Allreduce(&maxcolor_local, &maxcolor_global, 1, MPIU_INT, MPI_MAX, PetscObjectComm((PetscObject)mc)));
447:     PetscCallMPI(MPIU_Allreduce(&nadded, &nadded_total, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)mc)));
448:     PetscCheck(nadded_total != nadded_total_old, PetscObjectComm((PetscObject)mc), PETSC_ERR_NOT_CONVERGED, "JP didn't make progress");
449:     nadded_total_old = nadded_total;
450:   }
451:   PetscCall(PetscLogEventBegin(MATCOLORING_ISCreate, mc, 0, 0, 0));
452:   PetscCall(ISColoringCreate(PetscObjectComm((PetscObject)mc), maxcolor_global + 1, n, color, PETSC_OWN_POINTER, iscoloring));
453:   PetscCall(PetscLogEventEnd(MATCOLORING_ISCreate, mc, 0, 0, 0));
454:   PetscCall(PetscFree(jp->dwts));
455:   PetscCall(PetscFree(jp->dmask));
456:   PetscCall(PetscFree(jp->cmask));
457:   PetscCall(PetscFree(jp->owts));
458:   PetscCall(PetscFree(jp->omask));
459:   PetscCall(PetscFree(weights));
460:   PetscCall(PetscFree(lperm));
461:   PetscCall(PetscFree(maxweights));
462:   PetscCall(PetscFree(mincolor));
463:   PetscCall(PetscSFDestroy(&jp->sf));
464:   PetscFunctionReturn(PETSC_SUCCESS);
465: }

467: /*MC
468:   MATCOLORINGJP - Parallel Jones-Plassmann coloring {cite}`jp:pcolor`

470:    Level: beginner

472:    Options Database Key:
473: .  -mat_coloring_jp_local - perform a local coloring before applying the parallel algorithm

475:    Notes:
476:    This method uses a parallel Luby-style coloring with weights to choose an independent set of processor
477:    boundary vertices at each stage that may be assigned colors independently.

479:    Supports both distance one and distance two colorings.

481: .seealso: `MatColoring`, `MatColoringType`, `MatColoringCreate()`, `MatColoring`, `MatColoringSetType()`
482: M*/
483: PETSC_EXTERN PetscErrorCode MatColoringCreate_JP(MatColoring mc)
484: {
485:   MC_JP *jp;

487:   PetscFunctionBegin;
488:   PetscCall(PetscNew(&jp));
489:   jp->sf                  = NULL;
490:   jp->dmask               = NULL;
491:   jp->omask               = NULL;
492:   jp->cmask               = NULL;
493:   jp->dwts                = NULL;
494:   jp->owts                = NULL;
495:   jp->local               = PETSC_TRUE;
496:   mc->data                = jp;
497:   mc->ops->apply          = MatColoringApply_JP;
498:   mc->ops->view           = NULL;
499:   mc->ops->destroy        = MatColoringDestroy_JP;
500:   mc->ops->setfromoptions = MatColoringSetFromOptions_JP;
501:   PetscFunctionReturn(PETSC_SUCCESS);
502: }