Actual source code: mffd.c
petsc-3.6.4 2016-04-12
2: #include <petsc/private/matimpl.h>
3: #include <../src/mat/impls/mffd/mffdimpl.h> /*I "petscmat.h" I*/
5: PetscFunctionList MatMFFDList = 0;
6: PetscBool MatMFFDRegisterAllCalled = PETSC_FALSE;
8: PetscClassId MATMFFD_CLASSID;
9: PetscLogEvent MATMFFD_Mult;
11: static PetscBool MatMFFDPackageInitialized = PETSC_FALSE;
14: /*@C
15: MatMFFDFinalizePackage - This function destroys everything in the MatMFFD package. It is
16: called from PetscFinalize().
18: Level: developer
20: .keywords: Petsc, destroy, package
21: .seealso: PetscFinalize()
22: @*/
23: PetscErrorCode MatMFFDFinalizePackage(void)
24: {
28: PetscFunctionListDestroy(&MatMFFDList);
29: MatMFFDPackageInitialized = PETSC_FALSE;
30: MatMFFDRegisterAllCalled = PETSC_FALSE;
31: return(0);
32: }
36: /*@C
37: MatMFFDInitializePackage - This function initializes everything in the MatMFFD package. It is called
38: from PetscDLLibraryRegister() when using dynamic libraries, and on the first call to MatCreate_MFFD()
39: when using static libraries.
41: Level: developer
43: .keywords: Vec, initialize, package
44: .seealso: PetscInitialize()
45: @*/
46: PetscErrorCode MatMFFDInitializePackage(void)
47: {
48: char logList[256];
49: char *className;
50: PetscBool opt;
54: if (MatMFFDPackageInitialized) return(0);
55: MatMFFDPackageInitialized = PETSC_TRUE;
56: /* Register Classes */
57: PetscClassIdRegister("MatMFFD",&MATMFFD_CLASSID);
58: /* Register Constructors */
59: MatMFFDRegisterAll();
60: /* Register Events */
61: PetscLogEventRegister("MatMult MF", MATMFFD_CLASSID,&MATMFFD_Mult);
63: /* Process info exclusions */
64: PetscOptionsGetString(NULL, "-info_exclude", logList, 256, &opt);
65: if (opt) {
66: PetscStrstr(logList, "matmffd", &className);
67: if (className) {
68: PetscInfoDeactivateClass(MATMFFD_CLASSID);
69: }
70: }
71: /* Process summary exclusions */
72: PetscOptionsGetString(NULL, "-log_summary_exclude", logList, 256, &opt);
73: if (opt) {
74: PetscStrstr(logList, "matmffd", &className);
75: if (className) {
76: PetscLogEventDeactivateClass(MATMFFD_CLASSID);
77: }
78: }
79: PetscRegisterFinalize(MatMFFDFinalizePackage);
80: return(0);
81: }
85: /*@C
86: MatMFFDSetType - Sets the method that is used to compute the
87: differencing parameter for finite differene matrix-free formulations.
89: Input Parameters:
90: + mat - the "matrix-free" matrix created via MatCreateSNESMF(), or MatCreateMFFD()
91: or MatSetType(mat,MATMFFD);
92: - ftype - the type requested, either MATMFFD_WP or MATMFFD_DS
94: Level: advanced
96: Notes:
97: For example, such routines can compute h for use in
98: Jacobian-vector products of the form
100: F(x+ha) - F(x)
101: F'(u)a ~= ----------------
102: h
104: .seealso: MatCreateSNESMF(), MatMFFDRegister(), MatMFFDSetFunction()
105: @*/
106: PetscErrorCode MatMFFDSetType(Mat mat,MatMFFDType ftype)
107: {
108: PetscErrorCode ierr,(*r)(MatMFFD);
109: MatMFFD ctx = (MatMFFD)mat->data;
110: PetscBool match;
116: PetscObjectTypeCompare((PetscObject)mat,MATMFFD,&match);
117: if (!match) return(0);
119: /* already set, so just return */
120: PetscObjectTypeCompare((PetscObject)ctx,ftype,&match);
121: if (match) return(0);
123: /* destroy the old one if it exists */
124: if (ctx->ops->destroy) {
125: (*ctx->ops->destroy)(ctx);
126: }
128: PetscFunctionListFind(MatMFFDList,ftype,&r);
129: if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unknown MatMFFD type %s given",ftype);
130: (*r)(ctx);
131: PetscObjectChangeTypeName((PetscObject)ctx,ftype);
132: return(0);
133: }
135: typedef PetscErrorCode (*FCN1)(void*,Vec); /* force argument to next function to not be extern C*/
138: PetscErrorCode MatMFFDSetFunctioniBase_MFFD(Mat mat,FCN1 func)
139: {
140: MatMFFD ctx = (MatMFFD)mat->data;
143: ctx->funcisetbase = func;
144: return(0);
145: }
147: typedef PetscErrorCode (*FCN2)(void*,PetscInt,Vec,PetscScalar*); /* force argument to next function to not be extern C*/
150: PetscErrorCode MatMFFDSetFunctioni_MFFD(Mat mat,FCN2 funci)
151: {
152: MatMFFD ctx = (MatMFFD)mat->data;
155: ctx->funci = funci;
156: return(0);
157: }
161: PetscErrorCode MatMFFDResetHHistory_MFFD(Mat J)
162: {
163: MatMFFD ctx = (MatMFFD)J->data;
166: ctx->ncurrenth = 0;
167: return(0);
168: }
172: /*@C
173: MatMFFDRegister - Adds a method to the MatMFFD registry.
175: Not Collective
177: Input Parameters:
178: + name_solver - name of a new user-defined compute-h module
179: - routine_create - routine to create method context
181: Level: developer
183: Notes:
184: MatMFFDRegister() may be called multiple times to add several user-defined solvers.
186: Sample usage:
187: .vb
188: MatMFFDRegister("my_h",MyHCreate);
189: .ve
191: Then, your solver can be chosen with the procedural interface via
192: $ MatMFFDSetType(mfctx,"my_h")
193: or at runtime via the option
194: $ -mat_mffd_type my_h
196: .keywords: MatMFFD, register
198: .seealso: MatMFFDRegisterAll(), MatMFFDRegisterDestroy()
199: @*/
200: PetscErrorCode MatMFFDRegister(const char sname[],PetscErrorCode (*function)(MatMFFD))
201: {
205: PetscFunctionListAdd(&MatMFFDList,sname,function);
206: return(0);
207: }
209: /* ----------------------------------------------------------------------------------------*/
212: PetscErrorCode MatDestroy_MFFD(Mat mat)
213: {
215: MatMFFD ctx = (MatMFFD)mat->data;
218: VecDestroy(&ctx->w);
219: VecDestroy(&ctx->drscale);
220: VecDestroy(&ctx->dlscale);
221: VecDestroy(&ctx->dshift);
222: if (ctx->current_f_allocated) {
223: VecDestroy(&ctx->current_f);
224: }
225: if (ctx->ops->destroy) {(*ctx->ops->destroy)(ctx);}
226: PetscHeaderDestroy(&ctx);
227: mat->data = 0;
229: PetscObjectComposeFunction((PetscObject)mat,"MatMFFDSetBase_C",NULL);
230: PetscObjectComposeFunction((PetscObject)mat,"MatMFFDSetFunctioniBase_C",NULL);
231: PetscObjectComposeFunction((PetscObject)mat,"MatMFFDSetFunctioni_C",NULL);
232: PetscObjectComposeFunction((PetscObject)mat,"MatMFFDSetFunction_C",NULL);
233: PetscObjectComposeFunction((PetscObject)mat,"MatMFFDSetFunctionError_C",NULL);
234: PetscObjectComposeFunction((PetscObject)mat,"MatMFFDSetCheckh_C",NULL);
235: PetscObjectComposeFunction((PetscObject)mat,"MatMFFDSetPeriod_C",NULL);
236: PetscObjectComposeFunction((PetscObject)mat,"MatMFFDResetHHistory_C",NULL);
237: return(0);
238: }
242: /*
243: MatMFFDView_MFFD - Views matrix-free parameters.
245: */
246: PetscErrorCode MatView_MFFD(Mat J,PetscViewer viewer)
247: {
249: MatMFFD ctx = (MatMFFD)J->data;
250: PetscBool iascii, viewbase, viewfunction;
251: const char *prefix;
254: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
255: if (iascii) {
256: PetscViewerASCIIPrintf(viewer,"Matrix-free approximation:\n");
257: PetscViewerASCIIPushTab(viewer);
258: PetscViewerASCIIPrintf(viewer,"err=%g (relative error in function evaluation)\n",(double)ctx->error_rel);
259: if (!((PetscObject)ctx)->type_name) {
260: PetscViewerASCIIPrintf(viewer,"The compute h routine has not yet been set\n");
261: } else {
262: PetscViewerASCIIPrintf(viewer,"Using %s compute h routine\n",((PetscObject)ctx)->type_name);
263: }
264: if (ctx->ops->view) {
265: (*ctx->ops->view)(ctx,viewer);
266: }
267: PetscObjectGetOptionsPrefix((PetscObject)J, &prefix);
269: PetscOptionsHasName(prefix, "-mat_mffd_view_base", &viewbase);
270: if (viewbase) {
271: PetscViewerASCIIPrintf(viewer, "Base:\n");
272: VecView(ctx->current_u, viewer);
273: }
274: PetscOptionsHasName(prefix, "-mat_mffd_view_function", &viewfunction);
275: if (viewfunction) {
276: PetscViewerASCIIPrintf(viewer, "Function:\n");
277: VecView(ctx->current_f, viewer);
278: }
279: PetscViewerASCIIPopTab(viewer);
280: }
281: return(0);
282: }
286: /*
287: MatAssemblyEnd_MFFD - Resets the ctx->ncurrenth to zero. This
288: allows the user to indicate the beginning of a new linear solve by calling
289: MatAssemblyXXX() on the matrix free matrix. This then allows the
290: MatCreateMFFD_WP() to properly compute ||U|| only the first time
291: in the linear solver rather than every time.
293: This function is referenced directly from MatAssemblyEnd_SNESMF(), which may be in a different shared library.
294: */
295: PETSC_EXTERN PetscErrorCode MatAssemblyEnd_MFFD(Mat J,MatAssemblyType mt)
296: {
298: MatMFFD j = (MatMFFD)J->data;
301: MatMFFDResetHHistory(J);
302: j->vshift = 0.0;
303: j->vscale = 1.0;
304: return(0);
305: }
309: /*
310: MatMult_MFFD - Default matrix-free form for Jacobian-vector product, y = F'(u)*a:
312: y ~= (F(u + ha) - F(u))/h,
313: where F = nonlinear function, as set by SNESSetFunction()
314: u = current iterate
315: h = difference interval
316: */
317: PetscErrorCode MatMult_MFFD(Mat mat,Vec a,Vec y)
318: {
319: MatMFFD ctx = (MatMFFD)mat->data;
320: PetscScalar h;
321: Vec w,U,F;
323: PetscBool zeroa;
326: if (!ctx->current_u) SETERRQ(PetscObjectComm((PetscObject)mat),PETSC_ERR_ARG_WRONGSTATE,"MatMFFDSetBase() has not been called, this is often caused by forgetting to call \n\t\tMatAssemblyBegin/End on the first Mat in the SNES compute function");
327: /* We log matrix-free matrix-vector products separately, so that we can
328: separate the performance monitoring from the cases that use conventional
329: storage. We may eventually modify event logging to associate events
330: with particular objects, hence alleviating the more general problem. */
331: PetscLogEventBegin(MATMFFD_Mult,a,y,0,0);
333: w = ctx->w;
334: U = ctx->current_u;
335: F = ctx->current_f;
336: /*
337: Compute differencing parameter
338: */
339: if (!ctx->ops->compute) {
340: MatMFFDSetType(mat,MATMFFD_WP);
341: MatSetFromOptions(mat);
342: }
343: (*ctx->ops->compute)(ctx,U,a,&h,&zeroa);
344: if (zeroa) {
345: VecSet(y,0.0);
346: return(0);
347: }
349: if (mat->erroriffpe && PetscIsInfOrNanScalar(h)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Computed Nan differencing parameter h");
350: if (ctx->checkh) {
351: (*ctx->checkh)(ctx->checkhctx,U,a,&h);
352: }
354: /* keep a record of the current differencing parameter h */
355: ctx->currenth = h;
356: #if defined(PETSC_USE_COMPLEX)
357: PetscInfo2(mat,"Current differencing parameter: %g + %g i\n",(double)PetscRealPart(h),(double)PetscImaginaryPart(h));
358: #else
359: PetscInfo1(mat,"Current differencing parameter: %15.12e\n",h);
360: #endif
361: if (ctx->historyh && ctx->ncurrenth < ctx->maxcurrenth) {
362: ctx->historyh[ctx->ncurrenth] = h;
363: }
364: ctx->ncurrenth++;
366: /* w = u + ha */
367: if (ctx->drscale) {
368: VecPointwiseMult(ctx->drscale,a,U);
369: VecAYPX(U,h,w);
370: } else {
371: VecWAXPY(w,h,a,U);
372: }
374: /* compute func(U) as base for differencing; only needed first time in and not when provided by user */
375: if (ctx->ncurrenth == 1 && ctx->current_f_allocated) {
376: (*ctx->func)(ctx->funcctx,U,F);
377: }
378: (*ctx->func)(ctx->funcctx,w,y);
380: VecAXPY(y,-1.0,F);
381: VecScale(y,1.0/h);
383: if ((ctx->vshift != 0.0) || (ctx->vscale != 1.0)) {
384: VecAXPBY(y,ctx->vshift,ctx->vscale,a);
385: }
386: if (ctx->dlscale) {
387: VecPointwiseMult(y,ctx->dlscale,y);
388: }
389: if (ctx->dshift) {
390: VecPointwiseMult(ctx->dshift,a,U);
391: VecAXPY(y,1.0,U);
392: }
394: if (mat->nullsp) {MatNullSpaceRemove(mat->nullsp,y);}
396: PetscLogEventEnd(MATMFFD_Mult,a,y,0,0);
397: return(0);
398: }
402: /*
403: MatGetDiagonal_MFFD - Gets the diagonal for a matrix free matrix
405: y ~= (F(u + ha) - F(u))/h,
406: where F = nonlinear function, as set by SNESSetFunction()
407: u = current iterate
408: h = difference interval
409: */
410: PetscErrorCode MatGetDiagonal_MFFD(Mat mat,Vec a)
411: {
412: MatMFFD ctx = (MatMFFD)mat->data;
413: PetscScalar h,*aa,*ww,v;
414: PetscReal epsilon = PETSC_SQRT_MACHINE_EPSILON,umin = 100.0*PETSC_SQRT_MACHINE_EPSILON;
415: Vec w,U;
417: PetscInt i,rstart,rend;
420: if (!ctx->funci) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ORDER,"Requires calling MatMFFDSetFunctioni() first");
422: w = ctx->w;
423: U = ctx->current_u;
424: (*ctx->func)(ctx->funcctx,U,a);
425: (*ctx->funcisetbase)(ctx->funcctx,U);
426: VecCopy(U,w);
428: VecGetOwnershipRange(a,&rstart,&rend);
429: VecGetArray(a,&aa);
430: for (i=rstart; i<rend; i++) {
431: VecGetArray(w,&ww);
432: h = ww[i-rstart];
433: if (h == 0.0) h = 1.0;
434: if (PetscAbsScalar(h) < umin && PetscRealPart(h) >= 0.0) h = umin;
435: else if (PetscRealPart(h) < 0.0 && PetscAbsScalar(h) < umin) h = -umin;
436: h *= epsilon;
438: ww[i-rstart] += h;
439: VecRestoreArray(w,&ww);
440: (*ctx->funci)(ctx->funcctx,i,w,&v);
441: aa[i-rstart] = (v - aa[i-rstart])/h;
443: /* possibly shift and scale result */
444: if ((ctx->vshift != 0.0) || (ctx->vscale != 1.0)) {
445: aa[i - rstart] = ctx->vshift + ctx->vscale*aa[i-rstart];
446: }
448: VecGetArray(w,&ww);
449: ww[i-rstart] -= h;
450: VecRestoreArray(w,&ww);
451: }
452: VecRestoreArray(a,&aa);
453: return(0);
454: }
458: PetscErrorCode MatDiagonalScale_MFFD(Mat mat,Vec ll,Vec rr)
459: {
460: MatMFFD aij = (MatMFFD)mat->data;
464: if (ll && !aij->dlscale) {
465: VecDuplicate(ll,&aij->dlscale);
466: }
467: if (rr && !aij->drscale) {
468: VecDuplicate(rr,&aij->drscale);
469: }
470: if (ll) {
471: VecCopy(ll,aij->dlscale);
472: }
473: if (rr) {
474: VecCopy(rr,aij->drscale);
475: }
476: return(0);
477: }
481: PetscErrorCode MatDiagonalSet_MFFD(Mat mat,Vec ll,InsertMode mode)
482: {
483: MatMFFD aij = (MatMFFD)mat->data;
487: if (mode == INSERT_VALUES) SETERRQ(PetscObjectComm((PetscObject)mat),PETSC_ERR_SUP,"No diagonal set with INSERT_VALUES");
488: if (!aij->dshift) {
489: VecDuplicate(ll,&aij->dshift);
490: }
491: VecAXPY(aij->dshift,1.0,ll);
492: return(0);
493: }
497: PetscErrorCode MatShift_MFFD(Mat Y,PetscScalar a)
498: {
499: MatMFFD shell = (MatMFFD)Y->data;
502: shell->vshift += a;
503: return(0);
504: }
508: PetscErrorCode MatScale_MFFD(Mat Y,PetscScalar a)
509: {
510: MatMFFD shell = (MatMFFD)Y->data;
513: shell->vscale *= a;
514: return(0);
515: }
519: PETSC_EXTERN PetscErrorCode MatMFFDSetBase_MFFD(Mat J,Vec U,Vec F)
520: {
522: MatMFFD ctx = (MatMFFD)J->data;
525: MatMFFDResetHHistory(J);
527: ctx->current_u = U;
528: if (F) {
529: if (ctx->current_f_allocated) {VecDestroy(&ctx->current_f);}
530: ctx->current_f = F;
531: ctx->current_f_allocated = PETSC_FALSE;
532: } else if (!ctx->current_f_allocated) {
533: MatCreateVecs(J,NULL,&ctx->current_f);
535: ctx->current_f_allocated = PETSC_TRUE;
536: }
537: if (!ctx->w) {
538: VecDuplicate(ctx->current_u, &ctx->w);
539: }
540: J->assembled = PETSC_TRUE;
541: return(0);
542: }
544: typedef PetscErrorCode (*FCN3)(void*,Vec,Vec,PetscScalar*); /* force argument to next function to not be extern C*/
548: PetscErrorCode MatMFFDSetCheckh_MFFD(Mat J,FCN3 fun,void *ectx)
549: {
550: MatMFFD ctx = (MatMFFD)J->data;
553: ctx->checkh = fun;
554: ctx->checkhctx = ectx;
555: return(0);
556: }
560: /*@C
561: MatMFFDSetOptionsPrefix - Sets the prefix used for searching for all
562: MatMFFD options in the database.
564: Collective on Mat
566: Input Parameter:
567: + A - the Mat context
568: - prefix - the prefix to prepend to all option names
570: Notes:
571: A hyphen (-) must NOT be given at the beginning of the prefix name.
572: The first character of all runtime options is AUTOMATICALLY the hyphen.
574: Level: advanced
576: .keywords: SNES, matrix-free, parameters
578: .seealso: MatSetFromOptions(), MatCreateSNESMF()
579: @*/
580: PetscErrorCode MatMFFDSetOptionsPrefix(Mat mat,const char prefix[])
582: {
583: MatMFFD mfctx = mat ? (MatMFFD)mat->data : (MatMFFD)NULL;
589: PetscObjectSetOptionsPrefix((PetscObject)mfctx,prefix);
590: return(0);
591: }
595: PetscErrorCode MatSetFromOptions_MFFD(PetscOptions *PetscOptionsObject,Mat mat)
596: {
597: MatMFFD mfctx = (MatMFFD)mat->data;
599: PetscBool flg;
600: char ftype[256];
605: PetscObjectOptionsBegin((PetscObject)mfctx);
606: PetscOptionsFList("-mat_mffd_type","Matrix free type","MatMFFDSetType",MatMFFDList,((PetscObject)mfctx)->type_name,ftype,256,&flg);
607: if (flg) {
608: MatMFFDSetType(mat,ftype);
609: }
611: PetscOptionsReal("-mat_mffd_err","set sqrt relative error in function","MatMFFDSetFunctionError",mfctx->error_rel,&mfctx->error_rel,0);
612: PetscOptionsInt("-mat_mffd_period","how often h is recomputed","MatMFFDSetPeriod",mfctx->recomputeperiod,&mfctx->recomputeperiod,0);
614: flg = PETSC_FALSE;
615: PetscOptionsBool("-mat_mffd_check_positivity","Insure that U + h*a is nonnegative","MatMFFDSetCheckh",flg,&flg,NULL);
616: if (flg) {
617: MatMFFDSetCheckh(mat,MatMFFDCheckPositivity,0);
618: }
619: if (mfctx->ops->setfromoptions) {
620: (*mfctx->ops->setfromoptions)(PetscOptionsObject,mfctx);
621: }
622: PetscOptionsEnd();
623: return(0);
624: }
628: PetscErrorCode MatMFFDSetPeriod_MFFD(Mat mat,PetscInt period)
629: {
630: MatMFFD ctx = (MatMFFD)mat->data;
634: ctx->recomputeperiod = period;
635: return(0);
636: }
640: PetscErrorCode MatMFFDSetFunction_MFFD(Mat mat,PetscErrorCode (*func)(void*,Vec,Vec),void *funcctx)
641: {
642: MatMFFD ctx = (MatMFFD)mat->data;
645: ctx->func = func;
646: ctx->funcctx = funcctx;
647: return(0);
648: }
652: PetscErrorCode MatMFFDSetFunctionError_MFFD(Mat mat,PetscReal error)
653: {
654: MatMFFD ctx = (MatMFFD)mat->data;
658: if (error != PETSC_DEFAULT) ctx->error_rel = error;
659: return(0);
660: }
662: /*MC
663: MATMFFD - MATMFFD = "mffd" - A matrix free matrix type.
665: Level: advanced
667: .seealso: MatCreateMFFD(), MatCreateSNESMF(), MatMFFDSetFunction()
668: M*/
671: PETSC_EXTERN PetscErrorCode MatCreate_MFFD(Mat A)
672: {
673: MatMFFD mfctx;
677: MatMFFDInitializePackage();
679: PetscHeaderCreate(mfctx,MATMFFD_CLASSID,"MatMFFD","Matrix-free Finite Differencing","Mat",PetscObjectComm((PetscObject)A),MatDestroy_MFFD,MatView_MFFD);
681: mfctx->error_rel = PETSC_SQRT_MACHINE_EPSILON;
682: mfctx->recomputeperiod = 1;
683: mfctx->count = 0;
684: mfctx->currenth = 0.0;
685: mfctx->historyh = NULL;
686: mfctx->ncurrenth = 0;
687: mfctx->maxcurrenth = 0;
688: ((PetscObject)mfctx)->type_name = 0;
690: mfctx->vshift = 0.0;
691: mfctx->vscale = 1.0;
693: /*
694: Create the empty data structure to contain compute-h routines.
695: These will be filled in below from the command line options or
696: a later call with MatMFFDSetType() or if that is not called
697: then it will default in the first use of MatMult_MFFD()
698: */
699: mfctx->ops->compute = 0;
700: mfctx->ops->destroy = 0;
701: mfctx->ops->view = 0;
702: mfctx->ops->setfromoptions = 0;
703: mfctx->hctx = 0;
705: mfctx->func = 0;
706: mfctx->funcctx = 0;
707: mfctx->w = NULL;
709: A->data = mfctx;
711: A->ops->mult = MatMult_MFFD;
712: A->ops->destroy = MatDestroy_MFFD;
713: A->ops->view = MatView_MFFD;
714: A->ops->assemblyend = MatAssemblyEnd_MFFD;
715: A->ops->getdiagonal = MatGetDiagonal_MFFD;
716: A->ops->scale = MatScale_MFFD;
717: A->ops->shift = MatShift_MFFD;
718: A->ops->diagonalscale = MatDiagonalScale_MFFD;
719: A->ops->diagonalset = MatDiagonalSet_MFFD;
720: A->ops->setfromoptions = MatSetFromOptions_MFFD;
721: A->assembled = PETSC_TRUE;
723: PetscLayoutSetUp(A->rmap);
724: PetscLayoutSetUp(A->cmap);
726: PetscObjectComposeFunction((PetscObject)A,"MatMFFDSetBase_C",MatMFFDSetBase_MFFD);
727: PetscObjectComposeFunction((PetscObject)A,"MatMFFDSetFunctioniBase_C",MatMFFDSetFunctioniBase_MFFD);
728: PetscObjectComposeFunction((PetscObject)A,"MatMFFDSetFunctioni_C",MatMFFDSetFunctioni_MFFD);
729: PetscObjectComposeFunction((PetscObject)A,"MatMFFDSetFunction_C",MatMFFDSetFunction_MFFD);
730: PetscObjectComposeFunction((PetscObject)A,"MatMFFDSetCheckh_C",MatMFFDSetCheckh_MFFD);
731: PetscObjectComposeFunction((PetscObject)A,"MatMFFDSetPeriod_C",MatMFFDSetPeriod_MFFD);
732: PetscObjectComposeFunction((PetscObject)A,"MatMFFDSetFunctionError_C",MatMFFDSetFunctionError_MFFD);
733: PetscObjectComposeFunction((PetscObject)A,"MatMFFDResetHHistory_C",MatMFFDResetHHistory_MFFD);
735: mfctx->mat = A;
737: PetscObjectChangeTypeName((PetscObject)A,MATMFFD);
738: return(0);
739: }
743: /*@
744: MatCreateMFFD - Creates a matrix-free matrix. See also MatCreateSNESMF()
746: Collective on Vec
748: Input Parameters:
749: + comm - MPI communicator
750: . m - number of local rows (or PETSC_DECIDE to have calculated if M is given)
751: This value should be the same as the local size used in creating the
752: y vector for the matrix-vector product y = Ax.
753: . n - This value should be the same as the local size used in creating the
754: x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have
755: calculated if N is given) For square matrices n is almost always m.
756: . M - number of global rows (or PETSC_DETERMINE to have calculated if m is given)
757: - N - number of global columns (or PETSC_DETERMINE to have calculated if n is given)
760: Output Parameter:
761: . J - the matrix-free matrix
763: Options Database Keys: call MatSetFromOptions() to trigger these
764: + -mat_mffd_type - wp or ds (see MATMFFD_WP or MATMFFD_DS)
765: - -mat_mffd_err - square root of estimated relative error in function evaluation
766: - -mat_mffd_period - how often h is recomputed, defaults to 1, everytime
769: Level: advanced
771: Notes:
772: The matrix-free matrix context merely contains the function pointers
773: and work space for performing finite difference approximations of
774: Jacobian-vector products, F'(u)*a,
776: The default code uses the following approach to compute h
778: .vb
779: F'(u)*a = [F(u+h*a) - F(u)]/h where
780: h = error_rel*u'a/||a||^2 if |u'a| > umin*||a||_{1}
781: = error_rel*umin*sign(u'a)*||a||_{1}/||a||^2 otherwise
782: where
783: error_rel = square root of relative error in function evaluation
784: umin = minimum iterate parameter
785: .ve
787: You can call SNESSetJacobian() with MatMFFDComputeJacobian() if you are using matrix and not a different
788: preconditioner matrix
790: The user can set the error_rel via MatMFFDSetFunctionError() and
791: umin via MatMFFDDSSetUmin(); see Users-Manual: ch_snes for details.
793: The user should call MatDestroy() when finished with the matrix-free
794: matrix context.
796: Options Database Keys:
797: + -mat_mffd_err <error_rel> - Sets error_rel
798: . -mat_mffd_unim <umin> - Sets umin (for default PETSc routine that computes h only)
799: - -mat_mffd_check_positivity
801: .keywords: default, matrix-free, create, matrix
803: .seealso: MatDestroy(), MatMFFDSetFunctionError(), MatMFFDDSSetUmin(), MatMFFDSetFunction()
804: MatMFFDSetHHistory(), MatMFFDResetHHistory(), MatCreateSNESMF(),
805: MatMFFDGetH(), MatMFFDRegister(), MatMFFDComputeJacobian()
807: @*/
808: PetscErrorCode MatCreateMFFD(MPI_Comm comm,PetscInt m,PetscInt n,PetscInt M,PetscInt N,Mat *J)
809: {
813: MatCreate(comm,J);
814: MatSetSizes(*J,m,n,M,N);
815: MatSetType(*J,MATMFFD);
816: MatSetUp(*J);
817: return(0);
818: }
823: /*@
824: MatMFFDGetH - Gets the last value that was used as the differencing
825: parameter.
827: Not Collective
829: Input Parameters:
830: . mat - the matrix obtained with MatCreateSNESMF()
832: Output Paramter:
833: . h - the differencing step size
835: Level: advanced
837: .keywords: SNES, matrix-free, parameters
839: .seealso: MatCreateSNESMF(),MatMFFDSetHHistory(), MatCreateMFFD(), MATMFFD, MatMFFDResetHHistory()
840: @*/
841: PetscErrorCode MatMFFDGetH(Mat mat,PetscScalar *h)
842: {
843: MatMFFD ctx = (MatMFFD)mat->data;
845: PetscBool match;
848: PetscObjectTypeCompare((PetscObject)mat,MATMFFD,&match);
849: if (!match) SETERRQ(PetscObjectComm((PetscObject)mat),PETSC_ERR_ARG_WRONG,"Not a MFFD matrix");
851: *h = ctx->currenth;
852: return(0);
853: }
857: /*@C
858: MatMFFDSetFunction - Sets the function used in applying the matrix free.
860: Logically Collective on Mat
862: Input Parameters:
863: + mat - the matrix free matrix created via MatCreateSNESMF() or MatCreateMFFD()
864: . func - the function to use
865: - funcctx - optional function context passed to function
867: Calling Sequence of func:
868: $ func (void *funcctx, Vec x, Vec f)
870: + funcctx - user provided context
871: . x - input vector
872: - f - computed output function
874: Level: advanced
876: Notes:
877: If you use this you MUST call MatAssemblyBegin()/MatAssemblyEnd() on the matrix free
878: matrix inside your compute Jacobian routine
880: If this is not set then it will use the function set with SNESSetFunction() if MatCreateSNESMF() was used.
882: .keywords: SNES, matrix-free, function
884: .seealso: MatCreateSNESMF(),MatMFFDGetH(), MatCreateMFFD(), MATMFFD,
885: MatMFFDSetHHistory(), MatMFFDResetHHistory(), SNESetFunction()
886: @*/
887: PetscErrorCode MatMFFDSetFunction(Mat mat,PetscErrorCode (*func)(void*,Vec,Vec),void *funcctx)
888: {
892: PetscTryMethod(mat,"MatMFFDSetFunction_C",(Mat,PetscErrorCode (*)(void*,Vec,Vec),void*),(mat,func,funcctx));
893: return(0);
894: }
898: /*@C
899: MatMFFDSetFunctioni - Sets the function for a single component
901: Logically Collective on Mat
903: Input Parameters:
904: + mat - the matrix free matrix created via MatCreateSNESMF()
905: - funci - the function to use
907: Level: advanced
909: Notes:
910: If you use this you MUST call MatAssemblyBegin()/MatAssemblyEnd() on the matrix free
911: matrix inside your compute Jacobian routine
914: .keywords: SNES, matrix-free, function
916: .seealso: MatCreateSNESMF(),MatMFFDGetH(), MatMFFDSetHHistory(), MatMFFDResetHHistory(), SNESetFunction()
918: @*/
919: PetscErrorCode MatMFFDSetFunctioni(Mat mat,PetscErrorCode (*funci)(void*,PetscInt,Vec,PetscScalar*))
920: {
925: PetscTryMethod(mat,"MatMFFDSetFunctioni_C",(Mat,PetscErrorCode (*)(void*,PetscInt,Vec,PetscScalar*)),(mat,funci));
926: return(0);
927: }
932: /*@C
933: MatMFFDSetFunctioniBase - Sets the base vector for a single component function evaluation
935: Logically Collective on Mat
937: Input Parameters:
938: + mat - the matrix free matrix created via MatCreateSNESMF()
939: - func - the function to use
941: Level: advanced
943: Notes:
944: If you use this you MUST call MatAssemblyBegin()/MatAssemblyEnd() on the matrix free
945: matrix inside your compute Jacobian routine
948: .keywords: SNES, matrix-free, function
950: .seealso: MatCreateSNESMF(),MatMFFDGetH(), MatCreateMFFD(), MATMFFD
951: MatMFFDSetHHistory(), MatMFFDResetHHistory(), SNESetFunction()
952: @*/
953: PetscErrorCode MatMFFDSetFunctioniBase(Mat mat,PetscErrorCode (*func)(void*,Vec))
954: {
959: PetscTryMethod(mat,"MatMFFDSetFunctioniBase_C",(Mat,PetscErrorCode (*)(void*,Vec)),(mat,func));
960: return(0);
961: }
965: /*@
966: MatMFFDSetPeriod - Sets how often h is recomputed, by default it is everytime
968: Logically Collective on Mat
970: Input Parameters:
971: + mat - the matrix free matrix created via MatCreateSNESMF()
972: - period - 1 for everytime, 2 for every second etc
974: Options Database Keys:
975: + -mat_mffd_period <period>
977: Level: advanced
980: .keywords: SNES, matrix-free, parameters
982: .seealso: MatCreateSNESMF(),MatMFFDGetH(),
983: MatMFFDSetHHistory(), MatMFFDResetHHistory()
984: @*/
985: PetscErrorCode MatMFFDSetPeriod(Mat mat,PetscInt period)
986: {
990: PetscTryMethod(mat,"MatMFFDSetPeriod_C",(Mat,PetscInt),(mat,period));
991: return(0);
992: }
996: /*@
997: MatMFFDSetFunctionError - Sets the error_rel for the approximation of
998: matrix-vector products using finite differences.
1000: Logically Collective on Mat
1002: Input Parameters:
1003: + mat - the matrix free matrix created via MatCreateMFFD() or MatCreateSNESMF()
1004: - error_rel - relative error (should be set to the square root of
1005: the relative error in the function evaluations)
1007: Options Database Keys:
1008: + -mat_mffd_err <error_rel> - Sets error_rel
1010: Level: advanced
1012: Notes:
1013: The default matrix-free matrix-vector product routine computes
1014: .vb
1015: F'(u)*a = [F(u+h*a) - F(u)]/h where
1016: h = error_rel*u'a/||a||^2 if |u'a| > umin*||a||_{1}
1017: = error_rel*umin*sign(u'a)*||a||_{1}/||a||^2 else
1018: .ve
1020: .keywords: SNES, matrix-free, parameters
1022: .seealso: MatCreateSNESMF(),MatMFFDGetH(), MatCreateMFFD(), MATMFFD
1023: MatMFFDSetHHistory(), MatMFFDResetHHistory()
1024: @*/
1025: PetscErrorCode MatMFFDSetFunctionError(Mat mat,PetscReal error)
1026: {
1030: PetscTryMethod(mat,"MatMFFDSetFunctionError_C",(Mat,PetscReal),(mat,error));
1031: return(0);
1032: }
1036: /*@
1037: MatMFFDSetHHistory - Sets an array to collect a history of the
1038: differencing values (h) computed for the matrix-free product.
1040: Logically Collective on Mat
1042: Input Parameters:
1043: + J - the matrix-free matrix context
1044: . histroy - space to hold the history
1045: - nhistory - number of entries in history, if more entries are generated than
1046: nhistory, then the later ones are discarded
1048: Level: advanced
1050: Notes:
1051: Use MatMFFDResetHHistory() to reset the history counter and collect
1052: a new batch of differencing parameters, h.
1054: .keywords: SNES, matrix-free, h history, differencing history
1056: .seealso: MatMFFDGetH(), MatCreateSNESMF(),
1057: MatMFFDResetHHistory(), MatMFFDSetFunctionError()
1059: @*/
1060: PetscErrorCode MatMFFDSetHHistory(Mat J,PetscScalar history[],PetscInt nhistory)
1061: {
1062: MatMFFD ctx = (MatMFFD)J->data;
1064: PetscBool match;
1067: PetscObjectTypeCompare((PetscObject)J,MATMFFD,&match);
1068: if (!match) SETERRQ(PetscObjectComm((PetscObject)J),PETSC_ERR_ARG_WRONG,"Not a MFFD matrix");
1069: ctx->historyh = history;
1070: ctx->maxcurrenth = nhistory;
1071: ctx->currenth = 0.;
1072: return(0);
1073: }
1078: /*@
1079: MatMFFDResetHHistory - Resets the counter to zero to begin
1080: collecting a new set of differencing histories.
1082: Logically Collective on Mat
1084: Input Parameters:
1085: . J - the matrix-free matrix context
1087: Level: advanced
1089: Notes:
1090: Use MatMFFDSetHHistory() to create the original history counter.
1092: .keywords: SNES, matrix-free, h history, differencing history
1094: .seealso: MatMFFDGetH(), MatCreateSNESMF(),
1095: MatMFFDSetHHistory(), MatMFFDSetFunctionError()
1097: @*/
1098: PetscErrorCode MatMFFDResetHHistory(Mat J)
1099: {
1103: PetscTryMethod(J,"MatMFFDResetHHistory_C",(Mat),(J));
1104: return(0);
1105: }
1110: /*@
1111: MatMFFDSetBase - Sets the vector U at which matrix vector products of the
1112: Jacobian are computed
1114: Logically Collective on Mat
1116: Input Parameters:
1117: + J - the MatMFFD matrix
1118: . U - the vector
1119: - F - (optional) vector that contains F(u) if it has been already computed
1121: Notes: This is rarely used directly
1123: If F is provided then it is not recomputed. Otherwise the function is evaluated at the base
1124: point during the first MatMult() after each call to MatMFFDSetBase().
1126: Level: advanced
1128: @*/
1129: PetscErrorCode MatMFFDSetBase(Mat J,Vec U,Vec F)
1130: {
1137: PetscTryMethod(J,"MatMFFDSetBase_C",(Mat,Vec,Vec),(J,U,F));
1138: return(0);
1139: }
1143: /*@C
1144: MatMFFDSetCheckh - Sets a function that checks the computed h and adjusts
1145: it to satisfy some criteria
1147: Logically Collective on Mat
1149: Input Parameters:
1150: + J - the MatMFFD matrix
1151: . fun - the function that checks h
1152: - ctx - any context needed by the function
1154: Options Database Keys:
1155: . -mat_mffd_check_positivity
1157: Level: advanced
1159: Notes: For example, MatMFFDSetCheckPositivity() insures that all entries
1160: of U + h*a are non-negative
1162: .seealso: MatMFFDSetCheckPositivity()
1163: @*/
1164: PetscErrorCode MatMFFDSetCheckh(Mat J,PetscErrorCode (*fun)(void*,Vec,Vec,PetscScalar*),void *ctx)
1165: {
1170: PetscTryMethod(J,"MatMFFDSetCheckh_C",(Mat,PetscErrorCode (*)(void*,Vec,Vec,PetscScalar*),void*),(J,fun,ctx));
1171: return(0);
1172: }
1176: /*@
1177: MatMFFDCheckPositivity - Checks that all entries in U + h*a are positive or
1178: zero, decreases h until this is satisfied.
1180: Logically Collective on Vec
1182: Input Parameters:
1183: + U - base vector that is added to
1184: . a - vector that is added
1185: . h - scaling factor on a
1186: - dummy - context variable (unused)
1188: Options Database Keys:
1189: . -mat_mffd_check_positivity
1191: Level: advanced
1193: Notes: This is rarely used directly, rather it is passed as an argument to
1194: MatMFFDSetCheckh()
1196: .seealso: MatMFFDSetCheckh()
1197: @*/
1198: PetscErrorCode MatMFFDCheckPositivity(void *dummy,Vec U,Vec a,PetscScalar *h)
1199: {
1200: PetscReal val, minval;
1201: PetscScalar *u_vec, *a_vec;
1203: PetscInt i,n;
1204: MPI_Comm comm;
1207: PetscObjectGetComm((PetscObject)U,&comm);
1208: VecGetArray(U,&u_vec);
1209: VecGetArray(a,&a_vec);
1210: VecGetLocalSize(U,&n);
1211: minval = PetscAbsScalar(*h*1.01);
1212: for (i=0; i<n; i++) {
1213: if (PetscRealPart(u_vec[i] + *h*a_vec[i]) <= 0.0) {
1214: val = PetscAbsScalar(u_vec[i]/a_vec[i]);
1215: if (val < minval) minval = val;
1216: }
1217: }
1218: VecRestoreArray(U,&u_vec);
1219: VecRestoreArray(a,&a_vec);
1220: MPI_Allreduce(&minval,&val,1,MPIU_REAL,MPIU_MIN,comm);
1221: if (val <= PetscAbsScalar(*h)) {
1222: PetscInfo2(U,"Scaling back h from %g to %g\n",(double)PetscRealPart(*h),(double)(.99*val));
1223: if (PetscRealPart(*h) > 0.0) *h = 0.99*val;
1224: else *h = -0.99*val;
1225: }
1226: return(0);
1227: }