Actual source code: telescope_coarsedm.c
petsc-3.12.5 2020-03-29
2: #include <petsc/private/matimpl.h>
3: #include <petsc/private/pcimpl.h>
4: #include <petsc/private/dmimpl.h>
5: #include <petscksp.h>
6: #include <petscdm.h>
7: #include <petscdmda.h>
8: #include <petscdmshell.h>
10: #include "../src/ksp/pc/impls/telescope/telescope.h"
12: static PetscBool cited = PETSC_FALSE;
13: static const char citation[] =
14: "@inproceedings{MaySananRuppKnepleySmith2016,\n"
15: " title = {Extreme-Scale Multigrid Components within PETSc},\n"
16: " author = {Dave A. May and Patrick Sanan and Karl Rupp and Matthew G. Knepley and Barry F. Smith},\n"
17: " booktitle = {Proceedings of the Platform for Advanced Scientific Computing Conference},\n"
18: " series = {PASC '16},\n"
19: " isbn = {978-1-4503-4126-4},\n"
20: " location = {Lausanne, Switzerland},\n"
21: " pages = {5:1--5:12},\n"
22: " articleno = {5},\n"
23: " numpages = {12},\n"
24: " url = {https://doi.acm.org/10.1145/2929908.2929913},\n"
25: " doi = {10.1145/2929908.2929913},\n"
26: " acmid = {2929913},\n"
27: " publisher = {ACM},\n"
28: " address = {New York, NY, USA},\n"
29: " keywords = {GPU, HPC, agglomeration, coarse-level solver, multigrid, parallel computing, preconditioning},\n"
30: " year = {2016}\n"
31: "}\n";
33: typedef struct {
34: DM dm_fine,dm_coarse; /* these DM's should be topologically identical but use different communicators */
35: Mat permutation;
36: Vec xp;
37: PetscErrorCode (*fp_dm_field_scatter)(DM,Vec,ScatterMode,DM,Vec);
38: PetscErrorCode (*fp_dm_state_scatter)(DM,ScatterMode,DM);
39: void *dmksp_context_determined;
40: void *dmksp_context_user;
41: } PC_Telescope_CoarseDMCtx;
44: PetscErrorCode PCTelescopeSetUp_scatters_CoarseDM(PC pc,PC_Telescope sred,PC_Telescope_CoarseDMCtx *ctx)
45: {
47: Vec xred,yred,xtmp,x,xp;
48: VecScatter scatter;
49: IS isin;
50: Mat B;
51: PetscInt m,bs,st,ed;
52: MPI_Comm comm;
55: PetscObjectGetComm((PetscObject)pc,&comm);
56: PCGetOperators(pc,NULL,&B);
57: MatCreateVecs(B,&x,NULL);
58: MatGetBlockSize(B,&bs);
59: VecDuplicate(x,&xp);
60: m = 0;
61: xred = NULL;
62: yred = NULL;
63: if (PCTelescope_isActiveRank(sred)) {
64: DMCreateGlobalVector(ctx->dm_coarse,&xred);
65: VecDuplicate(xred,&yred);
66: VecGetOwnershipRange(xred,&st,&ed);
67: ISCreateStride(comm,ed-st,st,1,&isin);
68: VecGetLocalSize(xred,&m);
69: } else {
70: VecGetOwnershipRange(x,&st,&ed);
71: ISCreateStride(comm,0,st,1,&isin);
72: }
73: ISSetBlockSize(isin,bs);
74: VecCreate(comm,&xtmp);
75: VecSetSizes(xtmp,m,PETSC_DECIDE);
76: VecSetBlockSize(xtmp,bs);
77: VecSetType(xtmp,((PetscObject)x)->type_name);
78: VecScatterCreate(x,isin,xtmp,NULL,&scatter);
79: sred->xred = xred;
80: sred->yred = yred;
81: sred->isin = isin;
82: sred->scatter = scatter;
83: sred->xtmp = xtmp;
84: ctx->xp = xp;
85: VecDestroy(&x);
86: return(0);
87: }
89: PetscErrorCode PCTelescopeSetUp_CoarseDM(PC pc,PC_Telescope sred)
90: {
91: PC_Telescope_CoarseDMCtx *ctx;
92: DM dm,dm_coarse = NULL;
93: MPI_Comm comm;
94: PetscBool has_perm,has_kspcomputeoperators,using_kspcomputeoperators;
95: PetscErrorCode ierr;
98: PetscInfo(pc,"PCTelescope: setup (CoarseDM)\n");
99: PetscNew(&ctx);
100: sred->dm_ctx = (void*)ctx;
102: PetscObjectGetComm((PetscObject)pc,&comm);
103: PCGetDM(pc,&dm);
104: DMGetCoarseDM(dm,&dm_coarse);
105: ctx->dm_fine = dm;
106: ctx->dm_coarse = dm_coarse;
108: /* attach coarse dm to ksp on sub communicator */
109: if (PCTelescope_isActiveRank(sred)) {
110: KSPSetDM(sred->ksp,ctx->dm_coarse);
111: if (sred->ignore_kspcomputeoperators) {
112: KSPSetDMActive(sred->ksp,PETSC_FALSE);
113: }
114: }
116: /* check if there is a method to provide a permutation */
117: has_perm = PETSC_FALSE;
118: has_kspcomputeoperators = PETSC_FALSE;
119: using_kspcomputeoperators = PETSC_FALSE;
121: /* if no permutation is provided, we must rely on KSPSetComputeOperators */
122: {
123: PetscErrorCode (*dmfine_kspfunc)(KSP,Mat,Mat,void*) = NULL;
124: void *dmfine_kspctx = NULL,*dmcoarse_kspctx = NULL;
125: void *dmfine_appctx = NULL,*dmcoarse_appctx = NULL;
126: void *dmfine_shellctx = NULL,*dmcoarse_shellctx = NULL;
128: DMKSPGetComputeOperators(dm,&dmfine_kspfunc,&dmfine_kspctx);
129: if (dmfine_kspfunc) { has_kspcomputeoperators = PETSC_TRUE; }
131: DMGetApplicationContext(ctx->dm_fine,&dmfine_appctx);
132: DMShellGetContext(ctx->dm_fine,&dmfine_shellctx);
134: /* need to define dmcoarse_kspctx */
135: if (dmfine_kspfunc && !sred->ignore_kspcomputeoperators) {
137: PetscInfo(pc,"PCTelescope: KSPSetComputeOperators fetched from parent DM\n");
138: if (PCTelescope_isActiveRank(sred)) {
139: DMGetApplicationContext(ctx->dm_coarse,&dmcoarse_appctx);
140: DMShellGetContext(ctx->dm_coarse,&dmcoarse_shellctx);
141: }
143: /* Assume that if the fine operator didn't require any context, neither will the coarse */
144: if (!dmfine_kspctx) {
145: dmcoarse_kspctx = NULL;
146: PetscInfo(pc,"PCTelescope: KSPSetComputeOperators using NULL context\n");
147: } else {
149: PetscInfo(pc,"PCTelescope: KSPSetComputeOperators detected non-NULL context from parent DM \n");
150: if (PCTelescope_isActiveRank(sred)) {
152: if (dmfine_kspctx == dmfine_appctx) {
153: dmcoarse_kspctx = dmcoarse_appctx;
154: PetscInfo(pc,"PCTelescope: KSPSetComputeOperators using context from DM->ApplicationContext\n");
155: if (!dmcoarse_kspctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Non NULL dmfine->kspctx == dmfine->appctx. NULL dmcoarse->appctx found. Likely this is an error");
156: } else if (dmfine_kspctx == dmfine_shellctx) {
157: dmcoarse_kspctx = dmcoarse_shellctx;
158: PetscInfo(pc,"PCTelescope: KSPSetComputeOperators using context from DMShell->Context\n");
159: if (!dmcoarse_kspctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Non NULL dmfine->kspctx == dmfine.shell->ctx. NULL dmcoarse.shell->ctx found. Likely this is an error");
160: }
161: ctx->dmksp_context_determined = dmcoarse_kspctx;
163: /* look for user provided method to fetch the context */
164: {
165: PetscErrorCode (*fp_get_coarsedm_context)(DM,void**) = NULL;
166: void *dmcoarse_context_user = NULL;
167: char dmcoarse_method[PETSC_MAX_PATH_LEN];
169: PetscSNPrintf(dmcoarse_method,sizeof(dmcoarse_method),"PCTelescopeGetCoarseDMKSPContext");
170: PetscObjectQueryFunction((PetscObject)ctx->dm_coarse,dmcoarse_method,&fp_get_coarsedm_context);
171: if (fp_get_coarsedm_context) {
172: PetscInfo(pc,"PCTelescope: Found composed method PCTelescopeGetCoarseDMKSPContext from coarse DM\n");
173: fp_get_coarsedm_context(ctx->dm_coarse,&dmcoarse_context_user);
174: ctx->dmksp_context_user = dmcoarse_context_user;
175: dmcoarse_kspctx = dmcoarse_context_user;
176: } else {
177: PetscInfo(pc,"PCTelescope: Failed to find composed method PCTelescopeGetCoarseDMKSPContext from coarse DM\n");
178: }
179: }
181: if (!dmcoarse_kspctx) {
182: PetscInfo(pc,"PCTelescope: KSPSetComputeOperators failed to determine the context to use on sub-communicator\n");
183: SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Cannot determine which context with use for KSPSetComputeOperators() on sub-communicator");
184: }
185: }
186: }
187: }
189: if (dmfine_kspfunc && !sred->ignore_kspcomputeoperators) {
190: using_kspcomputeoperators = PETSC_TRUE;
192: if (PCTelescope_isActiveRank(sred)) {
193: /* sub ksp inherits dmksp_func and context provided by user */
194: KSPSetComputeOperators(sred->ksp,dmfine_kspfunc,dmcoarse_kspctx);
195: /*PetscObjectCopyFortranFunctionPointers((PetscObject)dm,(PetscObject)ctx->dmrepart);*/
196: KSPSetDMActive(sred->ksp,PETSC_TRUE);
197: }
198: }
199: }
201: if (!has_perm && has_kspcomputeoperators && !using_kspcomputeoperators) SETERRQ(comm,PETSC_ERR_SUP,"No method to permute an operator was found on the parent DM. A method for KSPSetComputeOperators() was provided but it was requested to be ignored. Telescope setup cannot proceed");
202: if (!has_perm && !has_kspcomputeoperators) SETERRQ(comm,PETSC_ERR_SUP,"No method to permute an operator was found on the parent DM. No method for KSPSetComputeOperators() was provided. Telescope setup cannot proceed");
204: {
205: char dmfine_method[PETSC_MAX_PATH_LEN];
207: PetscSNPrintf(dmfine_method,sizeof(dmfine_method),"PCTelescopeFieldScatter");
208: PetscObjectQueryFunction((PetscObject)ctx->dm_fine,dmfine_method,&ctx->fp_dm_field_scatter);
210: PetscSNPrintf(dmfine_method,sizeof(dmfine_method),"PCTelescopeStateScatter");
211: PetscObjectQueryFunction((PetscObject)ctx->dm_fine,dmfine_method,&ctx->fp_dm_state_scatter);
212: }
214: if (ctx->fp_dm_state_scatter) {
215: PetscInfo(pc,"PCTelescope: Found composed method PCTelescopeStateScatter from parent DM\n");
216: } else {
217: PetscInfo(pc,"PCTelescope: Failed to find composed method PCTelescopeStateScatter from parent DM\n");
218: }
220: if (ctx->fp_dm_field_scatter) {
221: PetscInfo(pc,"PCTelescope: Found composed method PCTelescopeFieldScatter from parent DM\n");
222: } else {
223: PetscInfo(pc,"PCTelescope: Failed to find composed method PCTelescopeFieldScatter from parent DM\n");
224: SETERRQ(comm,PETSC_ERR_SUP,"No method to scatter fields between the parent DM and coarse DM was found. Must call PetscObjectComposeFunction() with the parent DM. Telescope setup cannot proceed");
225: }
227: /*PCTelescopeSetUp_permutation_CoarseDM(pc,sred,ctx);*/
228: PCTelescopeSetUp_scatters_CoarseDM(pc,sred,ctx);
229: return(0);
230: }
232: PetscErrorCode PCApply_Telescope_CoarseDM(PC pc,Vec x,Vec y)
233: {
234: PC_Telescope sred = (PC_Telescope)pc->data;
235: PetscErrorCode ierr;
236: Vec xred,yred;
237: PC_Telescope_CoarseDMCtx *ctx;
240: ctx = (PC_Telescope_CoarseDMCtx*)sred->dm_ctx;
241: xred = sred->xred;
242: yred = sred->yred;
244: PetscCitationsRegister(citation,&cited);
246: if (ctx->fp_dm_state_scatter) {
247: ctx->fp_dm_state_scatter(ctx->dm_fine,SCATTER_FORWARD,ctx->dm_coarse);
248: }
250: ctx->fp_dm_field_scatter(ctx->dm_fine,x,SCATTER_FORWARD,ctx->dm_coarse,xred);
252: /* solve */
253: if (PCTelescope_isActiveRank(sred)) {
254: KSPSolve(sred->ksp,xred,yred);
255: }
257: ctx->fp_dm_field_scatter(ctx->dm_fine,y,SCATTER_REVERSE,ctx->dm_coarse,yred);
258: return(0);
259: }
261: PetscErrorCode PCTelescopeSubNullSpaceCreate_CoarseDM(PC pc,PC_Telescope sred,MatNullSpace nullspace,MatNullSpace *sub_nullspace)
262: {
263: PetscErrorCode ierr;
264: PetscBool has_const;
265: PetscInt k,n = 0;
266: const Vec *vecs;
267: Vec *sub_vecs = NULL;
268: MPI_Comm subcomm;
269: PC_Telescope_CoarseDMCtx *ctx;
272: ctx = (PC_Telescope_CoarseDMCtx*)sred->dm_ctx;
273: subcomm = sred->subcomm;
274: MatNullSpaceGetVecs(nullspace,&has_const,&n,&vecs);
276: if (PCTelescope_isActiveRank(sred)) {
277: /* create new vectors */
278: if (n) {
279: VecDuplicateVecs(sred->xred,n,&sub_vecs);
280: }
281: }
283: /* copy entries */
284: for (k=0; k<n; k++) {
285: ctx->fp_dm_field_scatter(ctx->dm_fine,vecs[k],SCATTER_FORWARD,ctx->dm_coarse,sub_vecs[k]);
286: }
288: if (PCTelescope_isActiveRank(sred)) {
289: /* create new (near) nullspace for redundant object */
290: MatNullSpaceCreate(subcomm,has_const,n,sub_vecs,sub_nullspace);
291: VecDestroyVecs(n,&sub_vecs);
292: }
293: return(0);
294: }
296: PetscErrorCode PCTelescopeMatNullSpaceCreate_CoarseDM(PC pc,PC_Telescope sred,Mat sub_mat)
297: {
298: PetscErrorCode ierr;
299: Mat B;
300: PC_Telescope_CoarseDMCtx *ctx;
303: ctx = (PC_Telescope_CoarseDMCtx*)sred->dm_ctx;
304: PCGetOperators(pc,NULL,&B);
305: {
306: MatNullSpace nullspace,sub_nullspace;
307: MatGetNullSpace(B,&nullspace);
308: if (nullspace) {
309: PetscInfo(pc,"PCTelescope: generating nullspace (CoarseDM)\n");
310: PCTelescopeSubNullSpaceCreate_CoarseDM(pc,sred,nullspace,&sub_nullspace);
312: /* attach any user nullspace removal methods and contexts */
313: if (PCTelescope_isActiveRank(sred)) {
314: void *context = NULL;
315: if (nullspace->remove && !nullspace->rmctx){
316: MatNullSpaceSetFunction(sub_nullspace,nullspace->remove,context);
317: } else if (nullspace->remove && nullspace->rmctx) {
318: char dmcoarse_method[PETSC_MAX_PATH_LEN];
319: PetscErrorCode (*fp_get_coarsedm_context)(DM,void**) = NULL;
321: PetscSNPrintf(dmcoarse_method,sizeof(dmcoarse_method),"PCTelescopeGetCoarseDMNullSpaceUserContext");
322: PetscObjectQueryFunction((PetscObject)ctx->dm_coarse,dmcoarse_method,&fp_get_coarsedm_context);
323: if (!context) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"Propagation of user null-space removal method with non-NULL context requires the coarse DM be composed with a function named \"%s\"",dmcoarse_method);
324: MatNullSpaceSetFunction(sub_nullspace,nullspace->remove,context);
325: }
326: }
328: if (PCTelescope_isActiveRank(sred)) {
329: MatSetNullSpace(sub_mat,sub_nullspace);
330: MatNullSpaceDestroy(&sub_nullspace);
331: }
332: }
333: }
334: {
335: MatNullSpace nearnullspace,sub_nearnullspace;
336: MatGetNearNullSpace(B,&nearnullspace);
337: if (nearnullspace) {
338: PetscInfo(pc,"PCTelescope: generating near nullspace (CoarseDM)\n");
339: PCTelescopeSubNullSpaceCreate_CoarseDM(pc,sred,nearnullspace,&sub_nearnullspace);
341: /* attach any user nullspace removal methods and contexts */
342: if (PCTelescope_isActiveRank(sred)) {
343: void *context = NULL;
344: if (nearnullspace->remove && !nearnullspace->rmctx){
345: MatNullSpaceSetFunction(sub_nearnullspace,nearnullspace->remove,context);
346: } else if (nearnullspace->remove && nearnullspace->rmctx) {
347: char dmcoarse_method[PETSC_MAX_PATH_LEN];
348: PetscErrorCode (*fp_get_coarsedm_context)(DM,void**) = NULL;
350: PetscSNPrintf(dmcoarse_method,sizeof(dmcoarse_method),"PCTelescopeGetCoarseDMNearNullSpaceUserContext");
351: PetscObjectQueryFunction((PetscObject)ctx->dm_coarse,dmcoarse_method,&fp_get_coarsedm_context);
352: if (!context) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"Propagation of user near null-space removal method with non-NULL context requires the coarse DM be composed with a function named \"%s\"",dmcoarse_method);
353: MatNullSpaceSetFunction(sub_nearnullspace,nearnullspace->remove,context);
354: }
355: }
357: if (PCTelescope_isActiveRank(sred)) {
358: MatSetNearNullSpace(sub_mat,sub_nearnullspace);
359: MatNullSpaceDestroy(&sub_nearnullspace);
360: }
361: }
362: }
363: return(0);
364: }
366: PetscErrorCode PCReset_Telescope_CoarseDM(PC pc)
367: {
368: PetscErrorCode ierr;
369: PC_Telescope sred = (PC_Telescope)pc->data;
370: PC_Telescope_CoarseDMCtx *ctx;
373: ctx = (PC_Telescope_CoarseDMCtx*)sred->dm_ctx;
374: ctx->dm_fine = NULL; /* since I did not increment the ref counter we set these to NULL */
375: ctx->dm_coarse = NULL; /* since I did not increment the ref counter we set these to NULL */
376: ctx->permutation = NULL; /* this will be fetched from the dm so no need to call destroy */
377: VecDestroy(&ctx->xp);
378: ctx->fp_dm_field_scatter = NULL;
379: ctx->fp_dm_state_scatter = NULL;
380: ctx->dmksp_context_determined = NULL;
381: ctx->dmksp_context_user = NULL;
382: return(0);
383: }
385: PetscErrorCode PCApplyRichardson_Telescope_CoarseDM(PC pc,Vec x,Vec y,Vec w,PetscReal rtol,PetscReal abstol,PetscReal dtol,PetscInt its,PetscBool zeroguess,PetscInt *outits,PCRichardsonConvergedReason *reason)
386: {
387: PC_Telescope sred = (PC_Telescope)pc->data;
388: PetscErrorCode ierr;
389: Vec yred = NULL;
390: PetscBool default_init_guess_value = PETSC_FALSE;
391: PC_Telescope_CoarseDMCtx *ctx;
394: ctx = (PC_Telescope_CoarseDMCtx*)sred->dm_ctx;
395: yred = sred->yred;
397: if (its > 1) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PCApplyRichardson_Telescope_CoarseDM only supports max_it = 1");
398: *reason = (PCRichardsonConvergedReason)0;
399:
400: if (!zeroguess) {
401: PetscInfo(pc,"PCTelescopeCoarseDM: Scattering y for non-zero-initial guess\n");
403: ctx->fp_dm_field_scatter(ctx->dm_fine,y,SCATTER_FORWARD,ctx->dm_coarse,yred);
404: }
406: if (PCTelescope_isActiveRank(sred)) {
407: KSPGetInitialGuessNonzero(sred->ksp,&default_init_guess_value);
408: if (!zeroguess) KSPSetInitialGuessNonzero(sred->ksp,PETSC_TRUE);
409: }
411: PCApply_Telescope_CoarseDM(pc,x,y);
413: if (PCTelescope_isActiveRank(sred)) {
414: KSPSetInitialGuessNonzero(sred->ksp,default_init_guess_value);
415: }
417: if (!*reason) *reason = PCRICHARDSON_CONVERGED_ITS;
418: *outits = 1;
419: return(0);
420: }