Actual source code: fas.c
1: /* Defines the basic SNES object */
2: #include <../src/snes/impls/fas/fasimpls.h>
4: const char *const SNESFASTypes[] = {"MULTIPLICATIVE", "ADDITIVE", "FULL", "KASKADE", "SNESFASType", "SNES_FAS", NULL};
6: static PetscErrorCode SNESReset_FAS(SNES snes)
7: {
8: SNES_FAS *fas = (SNES_FAS *)snes->data;
10: PetscFunctionBegin;
11: PetscCall(SNESDestroy(&fas->smoothu));
12: PetscCall(SNESDestroy(&fas->smoothd));
13: PetscCall(MatDestroy(&fas->inject));
14: PetscCall(MatDestroy(&fas->interpolate));
15: PetscCall(MatDestroy(&fas->restrct));
16: PetscCall(VecDestroy(&fas->rscale));
17: PetscCall(VecDestroy(&fas->Xg));
18: PetscCall(VecDestroy(&fas->Fg));
19: if (fas->next) PetscCall(SNESReset(fas->next));
20: PetscFunctionReturn(PETSC_SUCCESS);
21: }
23: static PetscErrorCode SNESDestroy_FAS(SNES snes)
24: {
25: SNES_FAS *fas = (SNES_FAS *)snes->data;
27: PetscFunctionBegin;
28: /* recursively resets and then destroys */
29: PetscCall(SNESReset_FAS(snes));
30: PetscCall(SNESDestroy(&fas->next));
31: PetscCall(PetscFree(fas));
32: PetscFunctionReturn(PETSC_SUCCESS);
33: }
35: static PetscErrorCode SNESFASSetUpLineSearch_Private(SNES snes, SNES smooth)
36: {
37: SNESLineSearch linesearch;
38: SNESLineSearch slinesearch;
39: void *lsprectx, *lspostctx;
40: PetscErrorCode (*precheck)(SNESLineSearch, Vec, Vec, PetscBool *, void *);
41: PetscErrorCode (*postcheck)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *);
43: PetscFunctionBegin;
44: if (!snes->linesearch) PetscFunctionReturn(PETSC_SUCCESS);
45: PetscCall(SNESGetLineSearch(snes, &linesearch));
46: PetscCall(SNESGetLineSearch(smooth, &slinesearch));
47: PetscCall(SNESLineSearchGetPreCheck(linesearch, &precheck, &lsprectx));
48: PetscCall(SNESLineSearchGetPostCheck(linesearch, &postcheck, &lspostctx));
49: PetscCall(SNESLineSearchSetPreCheck(slinesearch, precheck, lsprectx));
50: PetscCall(SNESLineSearchSetPostCheck(slinesearch, postcheck, lspostctx));
51: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)slinesearch));
52: PetscFunctionReturn(PETSC_SUCCESS);
53: }
55: static PetscErrorCode SNESFASCycleSetUpSmoother_Private(SNES snes, SNES smooth)
56: {
57: SNES_FAS *fas = (SNES_FAS *)snes->data;
59: PetscFunctionBegin;
60: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)snes, (PetscObject)smooth));
61: PetscCall(SNESSetFromOptions(smooth));
62: PetscCall(SNESFASSetUpLineSearch_Private(snes, smooth));
64: PetscCall(PetscObjectReference((PetscObject)snes->vec_sol));
65: PetscCall(PetscObjectReference((PetscObject)snes->vec_sol_update));
66: PetscCall(PetscObjectReference((PetscObject)snes->vec_func));
67: smooth->vec_sol = snes->vec_sol;
68: smooth->vec_sol_update = snes->vec_sol_update;
69: smooth->vec_func = snes->vec_func;
71: if (fas->eventsmoothsetup) PetscCall(PetscLogEventBegin(fas->eventsmoothsetup, smooth, 0, 0, 0));
72: PetscCall(SNESSetUp(smooth));
73: if (fas->eventsmoothsetup) PetscCall(PetscLogEventEnd(fas->eventsmoothsetup, smooth, 0, 0, 0));
74: PetscFunctionReturn(PETSC_SUCCESS);
75: }
77: static PetscErrorCode SNESSetUp_FAS(SNES snes)
78: {
79: SNES_FAS *fas = (SNES_FAS *)snes->data;
80: PetscInt dm_levels;
81: SNES next;
82: PetscBool isFine, hasCreateRestriction, hasCreateInjection;
84: PetscFunctionBegin;
85: PetscCall(SNESFASCycleIsFine(snes, &isFine));
86: if (fas->usedmfornumberoflevels && isFine) {
87: PetscCall(DMGetRefineLevel(snes->dm, &dm_levels));
88: dm_levels++;
89: if (dm_levels > fas->levels) {
90: /* reset the number of levels */
91: PetscCall(SNESFASSetLevels(snes, dm_levels, NULL));
92: PetscCall(SNESSetFromOptions(snes));
93: }
94: }
95: PetscCall(SNESFASCycleGetCorrection(snes, &next));
96: if (!isFine) snes->gridsequence = 0; /* no grid sequencing inside the multigrid hierarchy! */
98: PetscCall(SNESSetWorkVecs(snes, 2)); /* work vectors used for intergrid transfers */
100: /* set up the smoothers if they haven't already been set up */
101: if (!fas->smoothd) PetscCall(SNESFASCycleCreateSmoother_Private(snes, &fas->smoothd));
103: if (snes->dm) {
104: /* set the smoother DMs properly */
105: if (fas->smoothu) PetscCall(SNESSetDM(fas->smoothu, snes->dm));
106: PetscCall(SNESSetDM(fas->smoothd, snes->dm));
107: /* construct EVERYTHING from the DM -- including the progressive set of smoothers */
108: if (next) {
109: /* for now -- assume the DM and the evaluation functions have been set externally */
110: if (!next->dm) {
111: PetscCall(DMCoarsen(snes->dm, PetscObjectComm((PetscObject)next), &next->dm));
112: PetscCall(SNESSetDM(next, next->dm));
113: }
114: /* set the interpolation and restriction from the DM */
115: if (!fas->interpolate) {
116: PetscCall(DMCreateInterpolation(next->dm, snes->dm, &fas->interpolate, &fas->rscale));
117: if (!fas->restrct) {
118: PetscCall(DMHasCreateRestriction(next->dm, &hasCreateRestriction));
119: /* DM can create restrictions, use that */
120: if (hasCreateRestriction) {
121: PetscCall(DMCreateRestriction(next->dm, snes->dm, &fas->restrct));
122: } else {
123: PetscCall(PetscObjectReference((PetscObject)fas->interpolate));
124: fas->restrct = fas->interpolate;
125: }
126: }
127: }
128: /* set the injection from the DM */
129: if (!fas->inject) {
130: PetscCall(DMHasCreateInjection(next->dm, &hasCreateInjection));
131: if (hasCreateInjection) PetscCall(DMCreateInjection(next->dm, snes->dm, &fas->inject));
132: }
133: }
134: }
136: /*pass the smoother, function, and jacobian up to the next level if it's not user set already */
137: if (fas->galerkin) {
138: if (next) PetscCall(SNESSetFunction(next, NULL, SNESFASGalerkinFunctionDefault, next));
139: if (fas->smoothd && fas->level != fas->levels - 1) PetscCall(SNESSetFunction(fas->smoothd, NULL, SNESFASGalerkinFunctionDefault, snes));
140: if (fas->smoothu && fas->level != fas->levels - 1) PetscCall(SNESSetFunction(fas->smoothu, NULL, SNESFASGalerkinFunctionDefault, snes));
141: }
143: /* sets the down (pre) smoother's default norm and sets it from options */
144: if (fas->smoothd) {
145: if (fas->level == 0) {
146: PetscCall(SNESSetNormSchedule(fas->smoothd, SNES_NORM_ALWAYS));
147: } else {
148: PetscCall(SNESSetNormSchedule(fas->smoothd, SNES_NORM_FINAL_ONLY));
149: }
150: PetscCall(SNESFASCycleSetUpSmoother_Private(snes, fas->smoothd));
151: }
153: /* sets the up (post) smoother's default norm and sets it from options */
154: if (fas->smoothu) {
155: if (fas->level != fas->levels - 1) {
156: PetscCall(SNESSetNormSchedule(fas->smoothu, SNES_NORM_NONE));
157: } else {
158: PetscCall(SNESSetNormSchedule(fas->smoothu, SNES_NORM_FINAL_ONLY));
159: }
160: PetscCall(SNESFASCycleSetUpSmoother_Private(snes, fas->smoothu));
161: }
163: if (next) {
164: /* gotta set up the solution vector for this to work */
165: if (!next->vec_sol) PetscCall(SNESFASCreateCoarseVec(snes, &next->vec_sol));
166: if (!next->vec_rhs) PetscCall(SNESFASCreateCoarseVec(snes, &next->vec_rhs));
167: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)snes, (PetscObject)next));
168: PetscCall(SNESFASSetUpLineSearch_Private(snes, next));
169: PetscCall(SNESSetUp(next));
170: }
172: /* setup FAS work vectors */
173: if (fas->galerkin) {
174: PetscCall(VecDuplicate(snes->vec_sol, &fas->Xg));
175: PetscCall(VecDuplicate(snes->vec_sol, &fas->Fg));
176: }
177: PetscFunctionReturn(PETSC_SUCCESS);
178: }
180: static PetscErrorCode SNESSetFromOptions_FAS(SNES snes, PetscOptionItems PetscOptionsObject)
181: {
182: SNES_FAS *fas = (SNES_FAS *)snes->data;
183: PetscInt levels = 1;
184: PetscBool flg = PETSC_FALSE, upflg = PETSC_FALSE, downflg = PETSC_FALSE, monflg = PETSC_FALSE, galerkinflg = PETSC_FALSE, continuationflg = PETSC_FALSE;
185: SNESFASType fastype;
186: const char *optionsprefix;
187: SNESLineSearch linesearch;
188: PetscInt m, n_up, n_down;
189: SNES next;
190: PetscBool isFine;
192: PetscFunctionBegin;
193: PetscCall(SNESFASCycleIsFine(snes, &isFine));
194: PetscOptionsHeadBegin(PetscOptionsObject, "SNESFAS Options-----------------------------------");
196: /* number of levels -- only process most options on the finest level */
197: if (isFine) {
198: PetscCall(PetscOptionsInt("-snes_fas_levels", "Number of Levels", "SNESFASSetLevels", levels, &levels, &flg));
199: if (!flg && snes->dm) {
200: PetscCall(DMGetRefineLevel(snes->dm, &levels));
201: levels++;
202: fas->usedmfornumberoflevels = PETSC_TRUE;
203: }
204: PetscCall(SNESFASSetLevels(snes, levels, NULL));
205: fastype = fas->fastype;
206: PetscCall(PetscOptionsEnum("-snes_fas_type", "FAS correction type", "SNESFASSetType", SNESFASTypes, (PetscEnum)fastype, (PetscEnum *)&fastype, &flg));
207: if (flg) PetscCall(SNESFASSetType(snes, fastype));
209: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
210: PetscCall(PetscOptionsInt("-snes_fas_cycles", "Number of cycles", "SNESFASSetCycles", fas->n_cycles, &m, &flg));
211: if (flg) PetscCall(SNESFASSetCycles(snes, m));
212: PetscCall(PetscOptionsBool("-snes_fas_continuation", "Corrected grid-sequence continuation", "SNESFASSetContinuation", fas->continuation, &continuationflg, &flg));
213: if (flg) PetscCall(SNESFASSetContinuation(snes, continuationflg));
215: PetscCall(PetscOptionsBool("-snes_fas_galerkin", "Form coarse problems with Galerkin", "SNESFASSetGalerkin", fas->galerkin, &galerkinflg, &flg));
216: if (flg) PetscCall(SNESFASSetGalerkin(snes, galerkinflg));
218: if (fas->fastype == SNES_FAS_FULL) {
219: PetscCall(PetscOptionsBool("-snes_fas_full_downsweep", "Smooth on the initial down sweep for full FAS cycles", "SNESFASFullSetDownSweep", fas->full_downsweep, &fas->full_downsweep, &flg));
220: if (flg) PetscCall(SNESFASFullSetDownSweep(snes, fas->full_downsweep));
221: PetscCall(PetscOptionsBool("-snes_fas_full_total", "Use total restriction and interpolaton on the indial down and up sweeps for the full FAS cycle", "SNESFASFullSetUseTotal", fas->full_total, &fas->full_total, &flg));
222: if (flg) PetscCall(SNESFASFullSetTotal(snes, fas->full_total));
223: }
225: PetscCall(PetscOptionsInt("-snes_fas_smoothup", "Number of post-smoothing steps", "SNESFASSetNumberSmoothUp", fas->max_up_it, &n_up, &upflg));
227: PetscCall(PetscOptionsInt("-snes_fas_smoothdown", "Number of pre-smoothing steps", "SNESFASSetNumberSmoothDown", fas->max_down_it, &n_down, &downflg));
229: {
230: PetscViewer viewer;
231: PetscViewerFormat format;
232: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_fas_monitor", &viewer, &format, &monflg));
233: if (monflg) {
234: PetscViewerAndFormat *vf;
235: PetscCall(PetscViewerAndFormatCreate(viewer, format, &vf));
236: PetscCall(PetscViewerDestroy(&viewer));
237: PetscCall(SNESFASSetMonitor(snes, vf, PETSC_TRUE));
238: }
239: }
240: flg = PETSC_FALSE;
241: monflg = PETSC_TRUE;
242: PetscCall(PetscOptionsBool("-snes_fas_log", "Log times for each FAS level", "SNESFASSetLog", monflg, &monflg, &flg));
243: if (flg) PetscCall(SNESFASSetLog(snes, monflg));
244: }
245: PetscCall(PetscOptionsBool("-snes_fas_monitor_correction", "View the tau correction at each iteration", "SNESFASCoarseCorrection", fas->monitorCorrection, &fas->monitorCorrection, &flg));
247: PetscOptionsHeadEnd();
249: /* setup from the determined types if there is no pointwise procedure or smoother defined */
250: if (upflg) PetscCall(SNESFASSetNumberSmoothUp(snes, n_up));
251: if (downflg) PetscCall(SNESFASSetNumberSmoothDown(snes, n_down));
253: /* set up the default line search for coarse grid corrections */
254: if (fas->fastype == SNES_FAS_ADDITIVE) {
255: if (!snes->linesearch) {
256: PetscCall(SNESGetLineSearch(snes, &linesearch));
257: PetscCall(SNESLineSearchSetType(linesearch, SNESLINESEARCHSECANT));
258: }
259: }
261: /* recursive option setting for the smoothers */
262: PetscCall(SNESFASCycleGetCorrection(snes, &next));
263: if (next) PetscCall(SNESSetFromOptions(next));
264: PetscFunctionReturn(PETSC_SUCCESS);
265: }
267: #include <petscdraw.h>
268: static PetscErrorCode SNESView_FAS(SNES snes, PetscViewer viewer)
269: {
270: SNES_FAS *fas = (SNES_FAS *)snes->data;
271: PetscBool isFine, isascii, isdraw;
272: SNES smoothu, smoothd, levelsnes;
274: PetscFunctionBegin;
275: PetscCall(SNESFASCycleIsFine(snes, &isFine));
276: if (isFine) {
277: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
278: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
279: if (isascii) {
280: PetscCall(PetscViewerASCIIPrintf(viewer, " type is %s, levels=%" PetscInt_FMT ", cycles=%" PetscInt_FMT "\n", SNESFASTypes[fas->fastype], fas->levels, fas->n_cycles));
281: if (fas->galerkin) {
282: PetscCall(PetscViewerASCIIPrintf(viewer, " Using Galerkin computed coarse grid function evaluation\n"));
283: } else {
284: PetscCall(PetscViewerASCIIPrintf(viewer, " Not using Galerkin computed coarse grid function evaluation\n"));
285: }
286: for (PetscInt i = 0; i < fas->levels; i++) {
287: PetscCall(SNESFASGetCycleSNES(snes, i, &levelsnes));
288: PetscCall(SNESFASCycleGetSmootherUp(levelsnes, &smoothu));
289: PetscCall(SNESFASCycleGetSmootherDown(levelsnes, &smoothd));
290: if (!i) {
291: PetscCall(PetscViewerASCIIPrintf(viewer, " Coarse grid solver -- level %" PetscInt_FMT " -------------------------------\n", i));
292: } else {
293: PetscCall(PetscViewerASCIIPrintf(viewer, " Down solver (pre-smoother) on level %" PetscInt_FMT " -------------------------------\n", i));
294: }
295: PetscCall(PetscViewerASCIIPushTab(viewer));
296: if (smoothd) {
297: PetscCall(SNESView(smoothd, viewer));
298: } else {
299: PetscCall(PetscViewerASCIIPrintf(viewer, "Not yet available\n"));
300: }
301: PetscCall(PetscViewerASCIIPopTab(viewer));
302: if (i && (smoothd == smoothu)) {
303: PetscCall(PetscViewerASCIIPrintf(viewer, " Up solver (post-smoother) same as down solver (pre-smoother)\n"));
304: } else if (i) {
305: PetscCall(PetscViewerASCIIPrintf(viewer, " Up solver (post-smoother) on level %" PetscInt_FMT " -------------------------------\n", i));
306: PetscCall(PetscViewerASCIIPushTab(viewer));
307: if (smoothu) {
308: PetscCall(SNESView(smoothu, viewer));
309: } else {
310: PetscCall(PetscViewerASCIIPrintf(viewer, "Not yet available\n"));
311: }
312: PetscCall(PetscViewerASCIIPopTab(viewer));
313: }
314: }
315: } else if (isdraw) {
316: PetscDraw draw;
317: PetscReal x, w, y, bottom, th, wth;
318: SNES_FAS *curfas = fas;
319: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
320: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
321: PetscCall(PetscDrawStringGetSize(draw, &wth, &th));
322: bottom = y - th;
323: while (curfas) {
324: if (!curfas->smoothu) {
325: PetscCall(PetscDrawPushCurrentPoint(draw, x, bottom));
326: if (curfas->smoothd) PetscCall(SNESView(curfas->smoothd, viewer));
327: PetscCall(PetscDrawPopCurrentPoint(draw));
328: } else {
329: w = 0.5 * PetscMin(1.0 - x, x);
330: PetscCall(PetscDrawPushCurrentPoint(draw, x - w, bottom));
331: if (curfas->smoothd) PetscCall(SNESView(curfas->smoothd, viewer));
332: PetscCall(PetscDrawPopCurrentPoint(draw));
333: PetscCall(PetscDrawPushCurrentPoint(draw, x + w, bottom));
334: if (curfas->smoothu) PetscCall(SNESView(curfas->smoothu, viewer));
335: PetscCall(PetscDrawPopCurrentPoint(draw));
336: }
337: /* this is totally bogus but we have no way of knowing how low the previous one was draw to */
338: bottom -= 5 * th;
339: if (curfas->next) curfas = (SNES_FAS *)curfas->next->data;
340: else curfas = NULL;
341: }
342: }
343: }
344: PetscFunctionReturn(PETSC_SUCCESS);
345: }
347: /*
348: Defines the action of the downsmoother
349: */
350: static PetscErrorCode SNESFASDownSmooth_Private(SNES snes, Vec B, Vec X, Vec F, PetscReal *fnorm)
351: {
352: SNESConvergedReason reason;
353: Vec FPC;
354: SNES smoothd;
355: PetscBool flg;
356: SNES_FAS *fas = (SNES_FAS *)snes->data;
358: PetscFunctionBegin;
359: PetscCall(SNESFASCycleGetSmootherDown(snes, &smoothd));
360: PetscCall(SNESSetInitialFunction(smoothd, F));
361: if (fas->eventsmoothsolve) PetscCall(PetscLogEventBegin(fas->eventsmoothsolve, smoothd, B, X, 0));
362: PetscCall(SNESSolve(smoothd, B, X));
363: if (fas->eventsmoothsolve) PetscCall(PetscLogEventEnd(fas->eventsmoothsolve, smoothd, B, X, 0));
364: /* check convergence reason for the smoother */
365: PetscCall(SNESGetConvergedReason(smoothd, &reason));
366: if (reason < 0 && !(reason == SNES_DIVERGED_MAX_IT || reason == SNES_DIVERGED_LOCAL_MIN || reason == SNES_DIVERGED_LINE_SEARCH)) {
367: snes->reason = SNES_DIVERGED_INNER;
368: PetscFunctionReturn(PETSC_SUCCESS);
369: }
371: PetscCall(SNESGetFunction(smoothd, &FPC, NULL, NULL));
372: PetscCall(SNESGetAlwaysComputesFinalResidual(smoothd, &flg));
373: if (!flg) PetscCall(SNESComputeFunction(smoothd, X, FPC));
374: PetscCall(VecCopy(FPC, F));
375: if (fnorm) {
376: PetscCall(VecNorm(F, NORM_2, fnorm));
377: SNESCheckFunctionDomainError(snes, *fnorm);
378: }
379: PetscFunctionReturn(PETSC_SUCCESS);
380: }
382: /*
383: Defines the action of the upsmoother
384: */
385: static PetscErrorCode SNESFASUpSmooth_Private(SNES snes, Vec B, Vec X, Vec F, PetscReal *fnorm)
386: {
387: SNESConvergedReason reason;
388: Vec FPC;
389: SNES smoothu;
390: PetscBool flg;
391: SNES_FAS *fas = (SNES_FAS *)snes->data;
393: PetscFunctionBegin;
394: PetscCall(SNESFASCycleGetSmootherUp(snes, &smoothu));
395: if (fas->eventsmoothsolve) PetscCall(PetscLogEventBegin(fas->eventsmoothsolve, smoothu, 0, 0, 0));
396: PetscCall(SNESSolve(smoothu, B, X));
397: if (fas->eventsmoothsolve) PetscCall(PetscLogEventEnd(fas->eventsmoothsolve, smoothu, 0, 0, 0));
398: /* check convergence reason for the smoother */
399: PetscCall(SNESGetConvergedReason(smoothu, &reason));
400: if (reason < 0 && !(reason == SNES_DIVERGED_MAX_IT || reason == SNES_DIVERGED_LOCAL_MIN || reason == SNES_DIVERGED_LINE_SEARCH)) {
401: snes->reason = SNES_DIVERGED_INNER;
402: PetscFunctionReturn(PETSC_SUCCESS);
403: }
404: PetscCall(SNESGetFunction(smoothu, &FPC, NULL, NULL));
405: PetscCall(SNESGetAlwaysComputesFinalResidual(smoothu, &flg));
406: if (!flg) PetscCall(SNESComputeFunction(smoothu, X, FPC));
407: PetscCall(VecCopy(FPC, F));
408: if (fnorm) {
409: PetscCall(VecNorm(F, NORM_2, fnorm));
410: SNESCheckFunctionDomainError(snes, *fnorm);
411: }
412: PetscFunctionReturn(PETSC_SUCCESS);
413: }
415: /*@
416: SNESFASCreateCoarseVec - create a `Vec` corresponding to a state vector on one level coarser than the current level
418: Collective
420: Input Parameter:
421: . snes - `SNESFAS` object
423: Output Parameter:
424: . Xcoarse - vector on level one coarser than the current level
426: Level: developer
428: .seealso: [](ch_snes), `SNESFASSetRestriction()`, `SNESFASRestrict()`, `SNESFAS`
429: @*/
430: PetscErrorCode SNESFASCreateCoarseVec(SNES snes, Vec *Xcoarse)
431: {
432: SNES_FAS *fas;
434: PetscFunctionBegin;
436: PetscAssertPointer(Xcoarse, 2);
437: fas = (SNES_FAS *)snes->data;
438: if (fas->rscale) {
439: PetscCall(VecDuplicate(fas->rscale, Xcoarse));
440: } else if (fas->interpolate) {
441: PetscCall(MatCreateVecs(fas->interpolate, Xcoarse, NULL));
442: } else SETERRQ(PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONGSTATE, "Must set rscale or interpolation");
443: PetscFunctionReturn(PETSC_SUCCESS);
444: }
446: /*@
447: SNESFASRestrict - restrict a `Vec` to the next coarser level
449: Collective
451: Input Parameters:
452: + fine - `SNES` from which to restrict
453: - Xfine - vector to restrict
455: Output Parameter:
456: . Xcoarse - result of restriction
458: Level: developer
460: .seealso: [](ch_snes), `SNES`, `SNESFAS`, `SNESFASSetRestriction()`, `SNESFASSetInjection()`, `SNESFASCreateCoarseVec()`
461: @*/
462: PetscErrorCode SNESFASRestrict(SNES fine, Vec Xfine, Vec Xcoarse)
463: {
464: SNES_FAS *fas;
466: PetscFunctionBegin;
470: fas = (SNES_FAS *)fine->data;
471: if (fas->inject) {
472: PetscCall(MatRestrict(fas->inject, Xfine, Xcoarse));
473: } else {
474: PetscCall(MatRestrict(fas->restrct, Xfine, Xcoarse));
475: PetscCall(VecPointwiseMult(Xcoarse, fas->rscale, Xcoarse));
476: }
477: PetscFunctionReturn(PETSC_SUCCESS);
478: }
480: /*
481: Performs a variant of FAS using the interpolated total coarse solution
483: fine problem: F(x) = b
484: coarse problem: F^c(x^c) = Rb, Initial guess Rx
485: interpolated solution: x^f = I x^c (total solution interpolation
486: */
487: static PetscErrorCode SNESFASInterpolatedCoarseSolution(SNES snes, Vec X, Vec X_new)
488: {
489: Vec X_c, B_c;
490: SNESConvergedReason reason;
491: SNES next;
492: Mat restrct, interpolate;
493: SNES_FAS *fasc;
495: PetscFunctionBegin;
496: PetscCall(SNESFASCycleGetCorrection(snes, &next));
497: if (next) {
498: fasc = (SNES_FAS *)next->data;
500: PetscCall(SNESFASCycleGetRestriction(snes, &restrct));
501: PetscCall(SNESFASCycleGetInterpolation(snes, &interpolate));
503: X_c = next->vec_sol;
505: if (fasc->eventinterprestrict) PetscCall(PetscLogEventBegin(fasc->eventinterprestrict, snes, 0, 0, 0));
506: /* restrict the total solution: Rb */
507: PetscCall(SNESFASRestrict(snes, X, X_c));
508: B_c = next->vec_rhs;
509: if (snes->vec_rhs) {
510: /* restrict the total rhs defect: Rb */
511: PetscCall(MatRestrict(restrct, snes->vec_rhs, B_c));
512: } else {
513: PetscCall(VecSet(B_c, 0.));
514: }
515: if (fasc->eventinterprestrict) PetscCall(PetscLogEventEnd(fasc->eventinterprestrict, snes, 0, 0, 0));
517: PetscCall(SNESSolve(next, B_c, X_c));
518: PetscCall(SNESGetConvergedReason(next, &reason));
519: if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
520: snes->reason = SNES_DIVERGED_INNER;
521: PetscFunctionReturn(PETSC_SUCCESS);
522: }
523: /* x^f <- Ix^c*/
524: DM dmc, dmf;
526: PetscCall(SNESGetDM(next, &dmc));
527: PetscCall(SNESGetDM(snes, &dmf));
528: if (fasc->eventinterprestrict) PetscCall(PetscLogEventBegin(fasc->eventinterprestrict, snes, 0, 0, 0));
529: PetscCall(DMInterpolateSolution(dmc, dmf, interpolate, X_c, X_new));
530: if (fasc->eventinterprestrict) PetscCall(PetscLogEventEnd(fasc->eventinterprestrict, snes, 0, 0, 0));
531: PetscCall(PetscObjectSetName((PetscObject)X_c, "Coarse solution"));
532: PetscCall(VecViewFromOptions(X_c, NULL, "-fas_coarse_solution_view"));
533: PetscCall(PetscObjectSetName((PetscObject)X_new, "Updated Fine solution"));
534: PetscCall(VecViewFromOptions(X_new, NULL, "-fas_levels_1_solution_view"));
535: }
536: PetscFunctionReturn(PETSC_SUCCESS);
537: }
539: /*
540: Performs the FAS coarse correction as:
542: fine problem: F(x) = b
543: coarse problem: F^c(x^c) = b^c
545: b^c = F^c(Rx) - R(F(x) - b)
546: = tau + R b
547: */
548: static PetscErrorCode SNESFASCoarseCorrection(SNES snes, Vec X, Vec F, Vec X_new)
549: {
550: PetscBool monitorCorrection = ((SNES_FAS *)snes->data)->monitorCorrection;
551: Vec X_c, Xo_c, F_c, B_c;
552: SNESConvergedReason reason;
553: SNES next;
554: Mat restrct, interpolate;
555: SNES_FAS *fasc;
557: PetscFunctionBegin;
558: PetscCall(SNESFASCycleGetCorrection(snes, &next));
559: if (next) {
560: fasc = (SNES_FAS *)next->data;
562: PetscCall(SNESFASCycleGetRestriction(snes, &restrct));
563: PetscCall(SNESFASCycleGetInterpolation(snes, &interpolate));
565: X_c = next->vec_sol;
566: Xo_c = next->work[0];
567: F_c = next->vec_func;
568: B_c = next->vec_rhs;
570: if (fasc->eventinterprestrict) PetscCall(PetscLogEventBegin(fasc->eventinterprestrict, snes, 0, 0, 0));
571: PetscCall(SNESFASRestrict(snes, X, Xo_c));
572: /* restrict the defect: R(F(x) - b) */
573: PetscCall(MatRestrict(restrct, F, B_c));
574: if (monitorCorrection) {
575: PetscReal fnorm, rnorm;
577: PetscCall(VecNorm(F, NORM_2, &fnorm));
578: PetscCall(VecNorm(B_c, NORM_2, &rnorm));
579: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "||F(X)|| %g\n||R (F(X) - b)|| %g\n", (double)fnorm, (double)rnorm));
580: }
581: if (fasc->eventinterprestrict) PetscCall(PetscLogEventEnd(fasc->eventinterprestrict, snes, 0, 0, 0));
583: if (fasc->eventresidual) PetscCall(PetscLogEventBegin(fasc->eventresidual, next, 0, 0, 0));
584: /* F_c = F^c(Rx) - R(F(x) - b) since the second term was sitting in next->vec_rhs */
585: PetscCall(SNESComputeFunction(next, Xo_c, F_c));
586: if (monitorCorrection) {
587: PetscReal xnorm, fnorm;
589: PetscCall(VecNorm(Xo_c, NORM_2, &xnorm));
590: PetscCall(VecNorm(F_c, NORM_2, &fnorm));
591: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "||R(X)|| %g\n||tau + Rb = F_c (R X) - R(F(X) - b)|| %g\n", (double)xnorm, (double)fnorm));
592: PetscCall(PetscObjectSetName((PetscObject)F_c, "tau"));
593: PetscCall(VecViewFromOptions(F_c, (PetscObject)next, "-tau_view"));
594: }
595: if (fasc->eventresidual) PetscCall(PetscLogEventEnd(fasc->eventresidual, next, 0, 0, 0));
597: /* solve the coarse problem corresponding to F^c(x^c) = b^c = F^c(Rx) - R(F(x) - b) */
598: PetscCall(VecCopy(B_c, X_c)); // Now x^c holds R(F(x) - b)
599: PetscCall(VecCopy(F_c, B_c)); // Now b^c holds F^c(Rx) - R(F(x) - b)
600: PetscCall(VecCopy(X_c, F_c)); // Now F^c holds R(F(x) - b)
601: /* set initial guess of the coarse problem to the projected fine solution */
602: PetscCall(VecCopy(Xo_c, X_c));
604: /* recurse to the next level */
605: // So x^c_0 = R x and F^c_0 = F^c(x^c_0) - b^c = F^c(x^c_0) - (F^c(x^c_0) - R(F(x) - b)) = R(F(x) - b)
606: PetscCall(SNESSetInitialFunction(next, F_c));
607: PetscCall(SNESSolve(next, B_c, X_c));
608: PetscCall(SNESGetConvergedReason(next, &reason));
609: if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
610: snes->reason = SNES_DIVERGED_INNER;
611: PetscFunctionReturn(PETSC_SUCCESS);
612: }
613: /* correct as x <- x + I(x^c - Rx)*/
614: PetscCall(VecAXPY(X_c, -1.0, Xo_c));
616: if (fasc->eventinterprestrict) PetscCall(PetscLogEventBegin(fasc->eventinterprestrict, snes, 0, 0, 0));
617: PetscCall(MatInterpolateAdd(interpolate, X_c, X, X_new));
618: if (fasc->eventinterprestrict) PetscCall(PetscLogEventEnd(fasc->eventinterprestrict, snes, 0, 0, 0));
619: if (monitorCorrection) {
620: PetscReal xnorm, xonorm, inorm;
622: PetscCall(VecNorm(X_c, NORM_2, &xnorm));
623: PetscCall(VecNorm(X, NORM_2, &xonorm));
624: PetscCall(VecNorm(X_new, NORM_2, &inorm));
625: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "||X_c - Xo_c|| %g\n||X|| %g\n||X + I (X_c - X_co)|| %g\n", (double)xnorm, (double)xonorm, (double)inorm));
626: }
627: // TODO Check for snes->b, Technically we should strip out R b here if it is nonzero
628: PetscCall(PetscObjectSetName((PetscObject)B_c, "Tau correction"));
629: PetscCall(VecViewFromOptions(B_c, NULL, "-fas_tau_correction_view"));
630: PetscCall(PetscObjectSetName((PetscObject)X_c, "Coarse correction"));
631: PetscCall(VecViewFromOptions(X_c, NULL, "-fas_coarse_solution_view"));
632: PetscCall(PetscObjectSetName((PetscObject)X_new, "Updated Fine solution"));
633: PetscCall(VecViewFromOptions(X_new, NULL, "-fas_levels_1_solution_view"));
634: }
635: PetscFunctionReturn(PETSC_SUCCESS);
636: }
638: /*
639: The additive cycle is:
641: xhat = x
642: xhat = dS(x, b)
643: x = coarsecorrection(xhat, b_d)
644: x = x + nu*(xhat - x);
645: (optional) x = uS(x, b)
647: With the coarse RHS (defect correction) as below.
648: */
649: static PetscErrorCode SNESFASCycle_Additive(SNES snes, Vec X)
650: {
651: Vec F, B, Xhat;
652: Vec X_c, Xo_c, F_c, B_c;
653: SNESConvergedReason reason;
654: PetscReal xnorm, fnorm, ynorm;
655: SNES next;
656: Mat restrct, interpolate;
657: SNES_FAS *fas = (SNES_FAS *)snes->data, *fasc;
659: PetscFunctionBegin;
660: PetscCall(SNESFASCycleGetCorrection(snes, &next));
661: F = snes->vec_func;
662: B = snes->vec_rhs;
663: Xhat = snes->work[1];
664: PetscCall(VecCopy(X, Xhat));
665: /* recurse first */
666: if (next) {
667: fasc = (SNES_FAS *)next->data;
668: PetscCall(SNESFASCycleGetRestriction(snes, &restrct));
669: PetscCall(SNESFASCycleGetInterpolation(snes, &interpolate));
670: if (fas->eventresidual) PetscCall(PetscLogEventBegin(fas->eventresidual, snes, 0, 0, 0));
671: PetscCall(SNESComputeFunction(snes, Xhat, F));
672: if (fas->eventresidual) PetscCall(PetscLogEventEnd(fas->eventresidual, snes, 0, 0, 0));
673: PetscCall(VecNorm(F, NORM_2, &fnorm));
674: SNESCheckFunctionDomainError(snes, fnorm);
675: X_c = next->vec_sol;
676: Xo_c = next->work[0];
677: F_c = next->vec_func;
678: B_c = next->vec_rhs;
680: PetscCall(SNESFASRestrict(snes, Xhat, Xo_c));
681: /* restrict the defect */
682: PetscCall(MatRestrict(restrct, F, B_c));
684: /* solve the coarse problem corresponding to F^c(x^c) = b^c = Rb + F^c(Rx) - RF(x) */
685: if (fasc->eventresidual) PetscCall(PetscLogEventBegin(fasc->eventresidual, next, 0, 0, 0));
686: PetscCall(SNESComputeFunction(next, Xo_c, F_c));
687: if (fasc->eventresidual) PetscCall(PetscLogEventEnd(fasc->eventresidual, next, 0, 0, 0));
688: PetscCall(VecCopy(B_c, X_c));
689: PetscCall(VecCopy(F_c, B_c));
690: PetscCall(VecCopy(X_c, F_c));
691: /* set initial guess of the coarse problem to the projected fine solution */
692: PetscCall(VecCopy(Xo_c, X_c));
694: /* recurse */
695: PetscCall(SNESSetInitialFunction(next, F_c));
696: PetscCall(SNESSolve(next, B_c, X_c));
698: /* smooth on this level */
699: PetscCall(SNESFASDownSmooth_Private(snes, B, X, F, &fnorm));
701: PetscCall(SNESGetConvergedReason(next, &reason));
702: if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
703: snes->reason = SNES_DIVERGED_INNER;
704: PetscFunctionReturn(PETSC_SUCCESS);
705: }
707: /* correct as x <- x + I(x^c - Rx)*/
708: PetscCall(VecAYPX(X_c, -1.0, Xo_c));
709: PetscCall(MatInterpolate(interpolate, X_c, Xhat));
711: /* additive correction of the coarse direction*/
712: PetscCall(SNESLineSearchApply(snes->linesearch, X, F, &fnorm, Xhat));
713: PetscCall(SNESLineSearchGetNorms(snes->linesearch, &xnorm, &snes->norm, &ynorm));
714: SNESCheckLineSearchFailure(snes);
715: } else {
716: PetscCall(SNESFASDownSmooth_Private(snes, B, X, F, &snes->norm));
717: }
718: PetscFunctionReturn(PETSC_SUCCESS);
719: }
721: /*
722: Defines the FAS cycle as:
724: fine problem: F(x) = b
725: coarse problem: F^c(x) = b^c
727: b^c = F^c(Rx) - R(F(x) - b)
728: = F^c(Rx) - R(F(x)) + R b
729: = tau + R b
731: correction:
733: x = x + I(x^c - Rx)
734: */
735: static PetscErrorCode SNESFASCycle_Multiplicative(SNES snes, Vec X)
736: {
737: Vec F, B;
738: SNES next;
740: PetscFunctionBegin;
741: F = snes->vec_func;
742: B = snes->vec_rhs;
743: /* pre-smooth -- just update using the pre-smoother */
744: PetscCall(SNESFASCycleGetCorrection(snes, &next));
745: PetscCall(SNESFASDownSmooth_Private(snes, B, X, F, &snes->norm));
746: if (next) {
747: PetscCall(SNESFASCoarseCorrection(snes, X, F, X));
748: PetscCall(SNESFASUpSmooth_Private(snes, B, X, F, &snes->norm));
749: }
750: PetscFunctionReturn(PETSC_SUCCESS);
751: }
753: static PetscErrorCode SNESFASCycleSetupPhase_Full(SNES snes)
754: {
755: SNES next;
756: SNES_FAS *fas = (SNES_FAS *)snes->data;
757: PetscBool isFine;
759: PetscFunctionBegin;
760: /* pre-smooth -- just update using the pre-smoother */
761: PetscCall(SNESFASCycleIsFine(snes, &isFine));
762: PetscCall(SNESFASCycleGetCorrection(snes, &next));
763: fas->full_stage = 0;
764: if (next) PetscCall(SNESFASCycleSetupPhase_Full(next));
765: PetscFunctionReturn(PETSC_SUCCESS);
766: }
768: static PetscErrorCode SNESFASCycle_Full(SNES snes, Vec X)
769: {
770: Vec F, B;
771: SNES_FAS *fas = (SNES_FAS *)snes->data;
772: PetscBool isFine;
773: SNES next;
775: PetscFunctionBegin;
776: F = snes->vec_func;
777: B = snes->vec_rhs;
778: PetscCall(SNESFASCycleIsFine(snes, &isFine));
779: PetscCall(SNESFASCycleGetCorrection(snes, &next));
781: if (isFine) PetscCall(SNESFASCycleSetupPhase_Full(snes));
783: if (fas->full_stage == 0) {
784: /* downsweep */
785: if (next) {
786: if (fas->level != 1) next->max_its += 1;
787: if (fas->full_downsweep) PetscCall(SNESFASDownSmooth_Private(snes, B, X, F, &snes->norm));
788: fas->full_downsweep = PETSC_TRUE;
789: if (fas->full_total) PetscCall(SNESFASInterpolatedCoarseSolution(snes, X, X));
790: else PetscCall(SNESFASCoarseCorrection(snes, X, F, X));
791: fas->full_total = PETSC_FALSE;
792: PetscCall(SNESFASUpSmooth_Private(snes, B, X, F, &snes->norm));
793: if (fas->level != 1) next->max_its -= 1;
794: } else {
795: /* The smoother on the coarse level is the coarse solver */
796: PetscCall(SNESFASDownSmooth_Private(snes, B, X, F, &snes->norm));
797: }
798: fas->full_stage = 1;
799: } else if (fas->full_stage == 1) {
800: if (snes->iter == 0) PetscCall(SNESFASDownSmooth_Private(snes, B, X, F, &snes->norm));
801: if (next) {
802: PetscCall(SNESFASCoarseCorrection(snes, X, F, X));
803: PetscCall(SNESFASUpSmooth_Private(snes, B, X, F, &snes->norm));
804: }
805: }
806: /* final v-cycle */
807: if (isFine) {
808: if (next) {
809: PetscCall(SNESFASCoarseCorrection(snes, X, F, X));
810: PetscCall(SNESFASUpSmooth_Private(snes, B, X, F, &snes->norm));
811: }
812: }
813: PetscFunctionReturn(PETSC_SUCCESS);
814: }
816: static PetscErrorCode SNESFASCycle_Kaskade(SNES snes, Vec X)
817: {
818: Vec F, B;
819: SNES next;
821: PetscFunctionBegin;
822: F = snes->vec_func;
823: B = snes->vec_rhs;
824: PetscCall(SNESFASCycleGetCorrection(snes, &next));
825: if (next) {
826: PetscCall(SNESFASCoarseCorrection(snes, X, F, X));
827: PetscCall(SNESFASUpSmooth_Private(snes, B, X, F, &snes->norm));
828: } else {
829: PetscCall(SNESFASDownSmooth_Private(snes, B, X, F, &snes->norm));
830: }
831: PetscFunctionReturn(PETSC_SUCCESS);
832: }
834: PetscBool SNEScite = PETSC_FALSE;
835: const char SNESCitation[] = "@Article{bruneknepleysmithtu15,"
836: " title = {Composing Scalable Nonlinear Algebraic Solvers},"
837: " author = {Peter R. Brune and Matthew G. Knepley and Barry F. Smith and Xuemin Tu},"
838: " journal = {SIAM Review},"
839: " volume = {57},"
840: " number = {4},"
841: " pages = {535--565},"
842: " doi = {10.1137/130936725},"
843: " year = {2015}\n";
845: static PetscErrorCode SNESSolve_FAS(SNES snes)
846: {
847: Vec X, F;
848: PetscReal fnorm;
849: SNES_FAS *fas = (SNES_FAS *)snes->data, *ffas;
850: DM dm;
851: PetscBool isFine;
853: PetscFunctionBegin;
854: PetscCheck(!snes->xl && !snes->xu && !snes->ops->computevariablebounds, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONGSTATE, "SNES solver %s does not support bounds", ((PetscObject)snes)->type_name);
856: PetscCall(PetscCitationsRegister(SNESCitation, &SNEScite));
857: snes->reason = SNES_CONVERGED_ITERATING;
858: X = snes->vec_sol;
859: F = snes->vec_func;
861: PetscCall(SNESFASCycleIsFine(snes, &isFine));
862: /* norm setup */
863: PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
864: snes->iter = 0;
865: snes->norm = 0;
866: PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
867: if (!snes->vec_func_init_set) {
868: if (fas->eventresidual) PetscCall(PetscLogEventBegin(fas->eventresidual, snes, 0, 0, 0));
869: PetscCall(SNESComputeFunction(snes, X, F));
870: if (fas->eventresidual) PetscCall(PetscLogEventEnd(fas->eventresidual, snes, 0, 0, 0));
871: } else snes->vec_func_init_set = PETSC_FALSE;
873: PetscCall(VecNorm(F, NORM_2, &fnorm)); /* fnorm <- ||F|| */
874: SNESCheckFunctionDomainError(snes, fnorm);
875: PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
876: snes->norm = fnorm;
877: PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
878: PetscCall(SNESLogConvergenceHistory(snes, fnorm, 0));
880: /* test convergence */
881: PetscCall(SNESConverged(snes, snes->iter, 0.0, 0.0, fnorm));
882: PetscCall(SNESMonitor(snes, snes->iter, fnorm));
883: if (snes->reason) PetscFunctionReturn(PETSC_SUCCESS);
885: if (isFine) {
886: /* propagate scale-dependent data up the hierarchy */
887: PetscCall(SNESGetDM(snes, &dm));
888: for (ffas = fas; ffas->next; ffas = (SNES_FAS *)ffas->next->data) {
889: DM dmcoarse;
890: PetscCall(SNESGetDM(ffas->next, &dmcoarse));
891: PetscCall(DMRestrict(dm, ffas->restrct, ffas->rscale, ffas->inject, dmcoarse));
892: dm = dmcoarse;
893: }
894: }
896: for (PetscInt i = 0; i < snes->max_its; i++) {
897: /* Call general purpose update function */
898: PetscTryTypeMethod(snes, update, snes->iter);
900: if (fas->fastype == SNES_FAS_MULTIPLICATIVE) PetscCall(SNESFASCycle_Multiplicative(snes, X));
901: else if (fas->fastype == SNES_FAS_ADDITIVE) PetscCall(SNESFASCycle_Additive(snes, X));
902: else if (fas->fastype == SNES_FAS_FULL) PetscCall(SNESFASCycle_Full(snes, X));
903: else {
904: PetscCheck(fas->fastype == SNES_FAS_KASKADE, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONGSTATE, "Unsupported FAS type");
905: PetscCall(SNESFASCycle_Kaskade(snes, X));
906: }
908: /* check for FAS cycle divergence */
909: if (snes->reason != SNES_CONVERGED_ITERATING) PetscFunctionReturn(PETSC_SUCCESS);
911: /* Monitor convergence */
912: PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
913: snes->iter = i + 1;
914: PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
915: PetscCall(SNESLogConvergenceHistory(snes, snes->norm, 0));
916: PetscCall(SNESConverged(snes, snes->iter, 0.0, 0.0, snes->norm));
917: PetscCall(SNESMonitor(snes, snes->iter, snes->norm));
918: if (snes->reason) break;
919: }
920: PetscFunctionReturn(PETSC_SUCCESS);
921: }
923: /*MC
924: SNESFAS - An implementation of the Full Approximation Scheme nonlinear multigrid solver, FAS, or nonlinear multigrid {cite}`bruneknepleysmithtu15` for
925: solving nonlinear systems of equations with `SNES`.
927: The nonlinear problem is solved by correction using coarse versions
928: of the nonlinear problem. This problem is perturbed so that a projected
929: solution of the fine problem elicits no correction from the coarse problem.
931: Options Database Keys and Prefixes:
932: + -snes_fas_levels l - The number of levels
933: . -snes_fas_cycles (1|2) - The number of cycles -- 1 for V, 2 for W
934: . -snes_fas_type (additive|multiplicative|full|kaskade) - Additive or multiplicative cycle
935: . -snes_fas_galerkin (true|false) - Form coarse problems by projection back upon the fine problem
936: . -snes_fas_smoothup u - The number of iterations of the post-smoother
937: . -snes_fas_smoothdown d - The number of iterations of the pre-smoother
938: . -snes_fas_monitor - Monitor progress of all of the levels
939: . -snes_fas_full_downsweep (true|false) - call the downsmooth on the initial downsweep of full FAS
940: . -fas_levels_snes_ - prefix for `SNES` options for all smoothers
941: . -fas_levels_cycle_snes_ - prefix for `SNES` options for all cycles
942: . -fas_levels_i_snes_ - prefix `SNES` options for the smoothers on level i
943: . -fas_levels_i_cycle_snes_ - prefix for `SNES` options for the cycle on level i
944: - -fas_coarse_snes_ - prefix for `SNES` options for the coarsest smoother
946: Level: beginner
948: Note:
949: The organization of the `SNESFAS` solver is slightly different from the organization of `PCMG`
950: As each level has smoother `SNES` instances(down and potentially up) and a cycle `SNES` instance.
951: The cycle `SNES` instance may be used for monitoring convergence on a particular level.
953: .seealso: [](ch_snes), `PCMG`, `SNESCreate()`, `SNES`, `SNESSetType()`, `SNESType`, `SNESFASSetRestriction()`, `SNESFASSetInjection()`,
954: `SNESFASFullGetTotal()`, `SNESFASSetType()`, `SNESFASGetType()`, `SNESFASSetLevels()`, `SNESFASGetLevels()`, `SNESFASGetCycleSNES()`,
955: `SNESFASSetNumberSmoothUp()`, `SNESFASSetNumberSmoothDown()`, `SNESFASSetContinuation()`, `SNESFASSetCycles()`, `SNESFASSetMonitor()`,
956: `SNESFASSetLog()`, `SNESFASCycleSetCycles()`, `SNESFASCycleGetSmoother()`, `SNESFASCycleGetSmootherUp()`, `SNESFASCycleGetSmootherDown()`,
957: `SNESFASCycleGetCorrection()`, `SNESFASCycleGetInterpolation()`, `SNESFASCycleGetRestriction()`, `SNESFASCycleGetInjection()`,
958: `SNESFASCycleGetRScale()`, `SNESFASCycleIsFine()`, `SNESFASSetInterpolation()`, `SNESFASGetInterpolation()`,
959: `SNESFASGetRestriction()`, `SNESFASGetInjection()`, `SNESFASSetRScale()`, `SNESFASGetSmoother()`,
960: `SNESFASGetSmootherDown()`, `SNESFASGetSmootherUp()`, `SNESFASGetCoarseSolve()`, `SNESFASFullSetDownSweep()`, `SNESFASFullSetTotal()`
961: M*/
963: PETSC_EXTERN PetscErrorCode SNESCreate_FAS(SNES snes)
964: {
965: SNES_FAS *fas;
967: PetscFunctionBegin;
968: snes->ops->destroy = SNESDestroy_FAS;
969: snes->ops->setup = SNESSetUp_FAS;
970: snes->ops->setfromoptions = SNESSetFromOptions_FAS;
971: snes->ops->view = SNESView_FAS;
972: snes->ops->solve = SNESSolve_FAS;
973: snes->ops->reset = SNESReset_FAS;
975: snes->usesksp = PETSC_FALSE;
976: snes->usesnpc = PETSC_FALSE;
978: PetscCall(SNESParametersInitialize(snes));
979: PetscObjectParameterSetDefault(snes, max_funcs, 30000);
980: PetscObjectParameterSetDefault(snes, max_its, 10000);
982: snes->alwayscomputesfinalresidual = PETSC_TRUE;
984: PetscCall(PetscNew(&fas));
986: snes->data = (void *)fas;
987: fas->level = 0;
988: fas->levels = 1;
989: fas->n_cycles = 1;
990: fas->max_up_it = 1;
991: fas->max_down_it = 1;
992: fas->smoothu = NULL;
993: fas->smoothd = NULL;
994: fas->next = NULL;
995: fas->previous = NULL;
996: fas->fine = snes;
997: fas->interpolate = NULL;
998: fas->restrct = NULL;
999: fas->inject = NULL;
1000: fas->usedmfornumberoflevels = PETSC_FALSE;
1001: fas->fastype = SNES_FAS_MULTIPLICATIVE;
1002: fas->full_downsweep = PETSC_FALSE;
1003: fas->full_total = PETSC_FALSE;
1005: fas->eventsmoothsetup = 0;
1006: fas->eventsmoothsolve = 0;
1007: fas->eventresidual = 0;
1008: fas->eventinterprestrict = 0;
1009: PetscFunctionReturn(PETSC_SUCCESS);
1010: }