Actual source code: patch.c

  1: #include <petsc/private/dmpatchimpl.h>
  2: #include <petscdmda.h>
  3: #include <petscsf.h>

  5: /*
  6: Solver loop to update \tau:

  8:   DMZoom(dmc, &dmz)
  9:   DMRefine(dmz, &dmf),
 10:   Scatter Xcoarse -> Xzoom,
 11:   Interpolate Xzoom -> Xfine (note that this may be on subcomms),
 12:   Smooth Xfine using two-step smoother
 13:     normal smoother plus Kaczmarz---moves back and forth from dmzoom to dmfine
 14:   Compute residual Rfine
 15:   Restrict Rfine to Rzoom_restricted
 16:   Scatter Rzoom_restricted -> Rcoarse_restricted
 17:   Compute global residual Rcoarse
 18:   TauCoarse = Rcoarse - Rcoarse_restricted
 19: */

 21: /*@C
 22:   DMPatchZoom - Create patches of a DMDA on subsets of processes, indicated by commz

 24:   Collective on dm

 26:   Input Parameters:
 27:   + dm - the DM
 28:   . lower,upper - the upper right corner and the lower left corner of the requested patch
 29:   - commz - the new communicator for the patch, MPI_COMM_NULL indicates that the given rank will not own a patch

 31:   Output Parameters:
 32:   + dmz  - the patch DM
 33:   . sfz  - the PetscSF mapping the patch+halo to the zoomed version (optional)
 34:   - sfzr - the PetscSF mapping the patch to the restricted zoomed version

 36:   Level: intermediate

 38: .seealso: DMPatchSolve(), DMDACreatePatchIS()
 39: @*/
 40: PetscErrorCode DMPatchZoom(DM dm, MatStencil lower, MatStencil upper, MPI_Comm commz, DM *dmz, PetscSF *sfz, PetscSF *sfzr)
 41: {
 42:   DMDAStencilType st;
 43:   MatStencil      blower, bupper, loclower, locupper;
 44:   IS              is;
 45:   const PetscInt  *ranges, *indices;
 46:   PetscInt        *localPoints  = NULL;
 47:   PetscSFNode     *remotePoints = NULL;
 48:   PetscInt        dim, dof;
 49:   PetscInt        M, N, P, rM, rN, rP, halo = 1, sxb, syb, szb, sxr, syr, szr, exr, eyr, ezr, mxb, myb, mzb, i, j, k, l, q;
 50:   PetscMPIInt     size;
 51:   PetscBool       patchis_offproc = PETSC_TRUE;
 52:   Vec             X;

 54:   if (!sfz) halo = 0;
 55:   MPI_Comm_size(PetscObjectComm((PetscObject)dm), &size);
 56:   /* Create patch DM */
 57:   DMDAGetInfo(dm, &dim, &M, &N, &P, NULL,NULL,NULL, &dof, NULL,NULL,NULL,NULL, &st);

 59:   /* Get piece for rank r, expanded by halo */
 60:   bupper.i = PetscMin(M, upper.i + halo); blower.i = PetscMax(lower.i - halo, 0);
 61:   bupper.j = PetscMin(N, upper.j + halo); blower.j = PetscMax(lower.j - halo, 0);
 62:   bupper.k = PetscMin(P, upper.k + halo); blower.k = PetscMax(lower.k - halo, 0);
 63:   rM       = bupper.i - blower.i;
 64:   rN       = bupper.j - blower.j;
 65:   rP       = bupper.k - blower.k;

 67:   if (commz != MPI_COMM_NULL) {
 68:     DMDACreate(commz, dmz);
 69:     DMSetDimension(*dmz, dim);
 70:     DMDASetSizes(*dmz, rM, rN, rP);
 71:     DMDASetNumProcs(*dmz, PETSC_DECIDE, PETSC_DECIDE, PETSC_DECIDE);
 72:     DMDASetBoundaryType(*dmz, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE);
 73:     DMDASetDof(*dmz, dof);
 74:     DMDASetStencilType(*dmz, st);
 75:     DMDASetStencilWidth(*dmz, 0);
 76:     DMDASetOwnershipRanges(*dmz, NULL, NULL, NULL);
 77:     DMSetFromOptions(*dmz);
 78:     DMSetUp(*dmz);
 79:     DMDAGetCorners(*dmz, &sxb, &syb, &szb, &mxb, &myb, &mzb);
 80:     sxr  = PetscMax(sxb,     lower.i - blower.i);
 81:     syr  = PetscMax(syb,     lower.j - blower.j);
 82:     szr  = PetscMax(szb,     lower.k - blower.k);
 83:     exr  = PetscMin(sxb+mxb, upper.i - blower.i);
 84:     eyr  = PetscMin(syb+myb, upper.j - blower.j);
 85:     ezr  = PetscMin(szb+mzb, upper.k - blower.k);
 86:     PetscMalloc2(dof*rM*rN*PetscMax(rP,1),&localPoints,dof*rM*rN*PetscMax(rP,1),&remotePoints);
 87:   } else {
 88:     sxr = syr = szr = exr = eyr = ezr = sxb = syb = szb = mxb = myb = mzb = 0;
 89:   }

 91:   /* Create SF for restricted map */
 92:   DMCreateGlobalVector(dm,&X);
 93:   VecGetOwnershipRanges(X,&ranges);

 95:   loclower.i = blower.i + sxr; locupper.i = blower.i + exr;
 96:   loclower.j = blower.j + syr; locupper.j = blower.j + eyr;
 97:   loclower.k = blower.k + szr; locupper.k = blower.k + ezr;

 99:   DMDACreatePatchIS(dm, &loclower, &locupper, &is, patchis_offproc);
100:   ISGetIndices(is, &indices);

102:   if (dim < 3) {mzb = 1; ezr = 1;}
103:   q = 0;
104:   for (k = szb; k < szb+mzb; ++k) {
105:     if ((k < szr) || (k >= ezr)) continue;
106:     for (j = syb; j < syb+myb; ++j) {
107:       if ((j < syr) || (j >= eyr)) continue;
108:       for (i = sxb; i < sxb+mxb; ++i) {
109:         for (l=0; l<dof; l++) {
110:           const PetscInt lp = l + dof*(((k-szb)*rN + (j-syb))*rM + i-sxb);
111:           PetscInt       r;

113:           if ((i < sxr) || (i >= exr)) continue;
114:           localPoints[q]        = lp;
115:           PetscFindInt(indices[q], size+1, ranges, &r);

117:           remotePoints[q].rank  = r < 0 ? -(r+1) - 1 : r;
118:           remotePoints[q].index = indices[q] - ranges[remotePoints[q].rank];
119:           ++q;
120:         }
121:       }
122:     }
123:   }
124:   ISRestoreIndices(is, &indices);
125:   ISDestroy(&is);
126:   PetscSFCreate(PetscObjectComm((PetscObject)dm), sfzr);
127:   PetscObjectSetName((PetscObject) *sfzr, "Restricted Map");
128:   PetscSFSetGraph(*sfzr, dof*M*N*P, q, localPoints, PETSC_COPY_VALUES, remotePoints, PETSC_COPY_VALUES);

130:   if (sfz) {
131:     /* Create SF for buffered map */
132:     loclower.i = blower.i + sxb; locupper.i = blower.i + sxb+mxb;
133:     loclower.j = blower.j + syb; locupper.j = blower.j + syb+myb;
134:     loclower.k = blower.k + szb; locupper.k = blower.k + szb+mzb;

136:     DMDACreatePatchIS(dm, &loclower, &locupper, &is, patchis_offproc);
137:     ISGetIndices(is, &indices);

139:     q = 0;
140:     for (k = szb; k < szb+mzb; ++k) {
141:       for (j = syb; j < syb+myb; ++j) {
142:         for (i = sxb; i < sxb+mxb; ++i, ++q) {
143:           PetscInt r;

145:           localPoints[q]        = q;
146:           PetscFindInt(indices[q], size+1, ranges, &r);
147:           remotePoints[q].rank  = r < 0 ? -(r+1) - 1 : r;
148:           remotePoints[q].index = indices[q] - ranges[remotePoints[q].rank];
149:         }
150:       }
151:     }
152:     ISRestoreIndices(is, &indices);
153:     ISDestroy(&is);
154:     PetscSFCreate(PetscObjectComm((PetscObject)dm), sfz);
155:     PetscObjectSetName((PetscObject) *sfz, "Buffered Map");
156:     PetscSFSetGraph(*sfz, M*N*P, q, localPoints, PETSC_COPY_VALUES, remotePoints, PETSC_COPY_VALUES);
157:   }

159:   VecDestroy(&X);
160:   PetscFree2(localPoints, remotePoints);
161:   return 0;
162: }

164: typedef enum {PATCH_COMM_TYPE_WORLD = 0, PATCH_COMM_TYPE_SELF = 1} PatchCommType;

166: PetscErrorCode DMPatchSolve(DM dm)
167: {
168:   MPI_Comm       comm;
169:   MPI_Comm       commz;
170:   DM             dmc;
171:   PetscSF        sfz, sfzr;
172:   Vec            XC;
173:   MatStencil     patchSize, commSize, gridRank, lower, upper;
174:   PetscInt       M, N, P, i, j, k, l, m, n, p = 0;
175:   PetscMPIInt    rank, size;
176:   PetscInt       debug = 0;

178:   PetscObjectGetComm((PetscObject)dm,&comm);
179:   MPI_Comm_rank(comm, &rank);
180:   MPI_Comm_size(comm, &size);
181:   DMPatchGetCoarse(dm, &dmc);
182:   DMPatchGetPatchSize(dm, &patchSize);
183:   DMPatchGetCommSize(dm, &commSize);
184:   DMPatchGetCommSize(dm, &commSize);
185:   DMGetGlobalVector(dmc, &XC);
186:   DMDAGetInfo(dmc, NULL, &M, &N, &P, &l, &m, &n, NULL,NULL,NULL,NULL,NULL,NULL);
187:   M    = PetscMax(M, 1); l = PetscMax(l, 1);
188:   N    = PetscMax(N, 1); m = PetscMax(m, 1);
189:   P    = PetscMax(P, 1); n = PetscMax(n, 1);

191:   gridRank.i = rank       % l;
192:   gridRank.j = rank/l     % m;
193:   gridRank.k = rank/(l*m) % n;

195:   if (commSize.i*commSize.j*commSize.k == size || commSize.i*commSize.j*commSize.k == 0) {
196:     commSize.i = l; commSize.j = m; commSize.k = n;
197:     commz      = comm;
198:   } else if (commSize.i*commSize.j*commSize.k == 1) {
199:     commz = PETSC_COMM_SELF;
200:   } else {
201:     const PetscMPIInt newComm = ((gridRank.k/commSize.k)*(m/commSize.j) + gridRank.j/commSize.j)*(l/commSize.i) + (gridRank.i/commSize.i);
202:     const PetscMPIInt newRank = ((gridRank.k%commSize.k)*commSize.j     + gridRank.j%commSize.j)*commSize.i     + (gridRank.i%commSize.i);

204:     MPI_Comm_split(comm, newComm, newRank, &commz);
205:     if (debug) PetscPrintf(PETSC_COMM_SELF, "Rank %d color %d key %d commz %p\n", rank, newComm, newRank, (void*)(MPI_Aint)commz);
206:   }
207:   /*
208:    Assumptions:
209:      - patchSize divides gridSize
210:      - commSize divides gridSize
211:      - commSize divides l,m,n
212:    Ignore multiple patches per rank for now

214:    Multiple ranks per patch:
215:      - l,m,n divides patchSize
216:      - commSize divides patchSize
217:    */
218:   for (k = 0; k < P; k += PetscMax(patchSize.k, 1)) {
219:     for (j = 0; j < N; j += PetscMax(patchSize.j, 1)) {
220:       for (i = 0; i < M; i += PetscMax(patchSize.i, 1), ++p) {
221:         MPI_Comm    commp = MPI_COMM_NULL;
222:         DM          dmz   = NULL;
223: #if 0
224:         DM          dmf     = NULL;
225:         Mat         interpz = NULL;
226: #endif
227:         Vec         XZ       = NULL;
228:         PetscScalar *xcarray = NULL;
229:         PetscScalar *xzarray = NULL;

231:         if ((gridRank.k/commSize.k == p/(l/commSize.i * m/commSize.j) % n/commSize.k) &&
232:             (gridRank.j/commSize.j == p/(l/commSize.i)                % m/commSize.j) &&
233:             (gridRank.i/commSize.i == p                               % l/commSize.i)) {
234:           if (debug) PetscPrintf(PETSC_COMM_SELF, "Rank %d is accepting Patch %d\n", rank, p);
235:           commp = commz;
236:         }
237:         /* Zoom to coarse patch */
238:         lower.i = i; lower.j = j; lower.k = k;
239:         upper.i = i + patchSize.i; upper.j = j + patchSize.j; upper.k = k + patchSize.k;
240:         DMPatchZoom(dmc, lower, upper, commp, &dmz, &sfz, &sfzr);
241:         lower.c = 0; /* initialize member, otherwise compiler issues warnings */
242:         upper.c = 0; /* initialize member, otherwise compiler issues warnings */
243:         if (debug) PetscPrintf(comm, "Patch %d: (%d, %d, %d)--(%d, %d, %d)\n", p, lower.i, lower.j, lower.k, upper.i, upper.j, upper.k);
244:         if (dmz) DMView(dmz, PETSC_VIEWER_STDOUT_(commz));
245:         PetscSFView(sfz,  PETSC_VIEWER_STDOUT_(comm));
246:         PetscSFView(sfzr, PETSC_VIEWER_STDOUT_(comm));
247:         /* Scatter Xcoarse -> Xzoom */
248:         if (dmz) DMGetGlobalVector(dmz, &XZ);
249:         if (XZ)  VecGetArray(XZ, &xzarray);
250:         VecGetArray(XC, &xcarray);
251:         PetscSFBcastBegin(sfz, MPIU_SCALAR, xcarray, xzarray,MPI_REPLACE);
252:         PetscSFBcastEnd(sfz, MPIU_SCALAR, xcarray, xzarray,MPI_REPLACE);
253:         VecRestoreArray(XC, &xcarray);
254:         if (XZ)  VecRestoreArray(XZ, &xzarray);
255: #if 0
256:         /* Interpolate Xzoom -> Xfine, note that this may be on subcomms */
257:         DMRefine(dmz, MPI_COMM_NULL, &dmf);
258:         DMCreateInterpolation(dmz, dmf, &interpz, NULL);
259:         DMInterpolate(dmz, interpz, dmf);
260:         /* Smooth Xfine using two-step smoother, normal smoother plus Kaczmarz---moves back and forth from dmzoom to dmfine */
261:         /* Compute residual Rfine */
262:         /* Restrict Rfine to Rzoom_restricted */
263: #endif
264:         /* Scatter Rzoom_restricted -> Rcoarse_restricted */
265:         if (XZ)  VecGetArray(XZ, &xzarray);
266:         VecGetArray(XC, &xcarray);
267:         PetscSFReduceBegin(sfzr, MPIU_SCALAR, xzarray, xcarray, MPIU_SUM);
268:         PetscSFReduceEnd(sfzr, MPIU_SCALAR, xzarray, xcarray, MPIU_SUM);
269:         VecRestoreArray(XC, &xcarray);
270:         if (XZ)  VecRestoreArray(XZ, &xzarray);
271:         if (dmz) DMRestoreGlobalVector(dmz, &XZ);
272:         /* Compute global residual Rcoarse */
273:         /* TauCoarse = Rcoarse - Rcoarse_restricted */

275:         PetscSFDestroy(&sfz);
276:         PetscSFDestroy(&sfzr);
277:         DMDestroy(&dmz);
278:       }
279:     }
280:   }
281:   DMRestoreGlobalVector(dmc, &XC);
282:   return 0;
283: }

285: PetscErrorCode DMPatchView_ASCII(DM dm, PetscViewer viewer)
286: {
287:   DM_Patch          *mesh = (DM_Patch*) dm->data;
288:   PetscViewerFormat format;
289:   const char        *name;

291:   PetscViewerGetFormat(viewer, &format);
292:   /* if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) */
293:   PetscObjectGetName((PetscObject) dm, &name);
294:   PetscViewerASCIIPrintf(viewer, "Patch DM %s\n", name);
295:   PetscViewerASCIIPushTab(viewer);
296:   PetscViewerASCIIPrintf(viewer, "Coarse DM\n");
297:   DMView(mesh->dmCoarse, viewer);
298:   PetscViewerASCIIPopTab(viewer);
299:   return 0;
300: }

302: PetscErrorCode DMView_Patch(DM dm, PetscViewer viewer)
303: {
304:   PetscBool      iascii, isbinary;

308:   PetscObjectTypeCompare((PetscObject) viewer, PETSCVIEWERASCII, &iascii);
309:   PetscObjectTypeCompare((PetscObject) viewer, PETSCVIEWERBINARY, &isbinary);
310:   if (iascii) {
311:     DMPatchView_ASCII(dm, viewer);
312:   }
313:   return 0;
314: }

316: PetscErrorCode DMDestroy_Patch(DM dm)
317: {
318:   DM_Patch       *mesh = (DM_Patch*) dm->data;

320:   if (--mesh->refct > 0) return 0;
321:   DMDestroy(&mesh->dmCoarse);
322:   /* This was originally freed in DMDestroy(), but that prevents reference counting of backend objects */
323:   PetscFree(mesh);
324:   return 0;
325: }

327: PetscErrorCode DMSetUp_Patch(DM dm)
328: {
329:   DM_Patch       *mesh = (DM_Patch*) dm->data;

332:   DMSetUp(mesh->dmCoarse);
333:   return 0;
334: }

336: PetscErrorCode DMCreateGlobalVector_Patch(DM dm, Vec *g)
337: {
338:   DM_Patch       *mesh = (DM_Patch*) dm->data;

341:   DMCreateGlobalVector(mesh->dmCoarse, g);
342:   return 0;
343: }

345: PetscErrorCode DMCreateLocalVector_Patch(DM dm, Vec *l)
346: {
347:   DM_Patch       *mesh = (DM_Patch*) dm->data;

350:   DMCreateLocalVector(mesh->dmCoarse, l);
351:   return 0;
352: }

354: PetscErrorCode DMCreateSubDM_Patch(DM dm, PetscInt numFields, const PetscInt fields[], IS *is, DM *subdm)
355: {
356:   SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_SUP, "Tell me to code this");
357: }

359: PetscErrorCode DMPatchGetCoarse(DM dm, DM *dmCoarse)
360: {
361:   DM_Patch *mesh = (DM_Patch*) dm->data;

364:   *dmCoarse = mesh->dmCoarse;
365:   return 0;
366: }

368: PetscErrorCode DMPatchGetPatchSize(DM dm, MatStencil *patchSize)
369: {
370:   DM_Patch *mesh = (DM_Patch*) dm->data;

374:   *patchSize = mesh->patchSize;
375:   return 0;
376: }

378: PetscErrorCode DMPatchSetPatchSize(DM dm, MatStencil patchSize)
379: {
380:   DM_Patch *mesh = (DM_Patch*) dm->data;

383:   mesh->patchSize = patchSize;
384:   return 0;
385: }

387: PetscErrorCode DMPatchGetCommSize(DM dm, MatStencil *commSize)
388: {
389:   DM_Patch *mesh = (DM_Patch*) dm->data;

393:   *commSize = mesh->commSize;
394:   return 0;
395: }

397: PetscErrorCode DMPatchSetCommSize(DM dm, MatStencil commSize)
398: {
399:   DM_Patch *mesh = (DM_Patch*) dm->data;

402:   mesh->commSize = commSize;
403:   return 0;
404: }