Actual source code: fdmatrix.c
petsc-3.3-p7 2013-05-11
2: /*
3: This is where the abstract matrix operations are defined that are
4: used for finite difference computations of Jacobians using coloring.
5: */
7: #include <petsc-private/matimpl.h> /*I "petscmat.h" I*/
11: PetscErrorCode MatFDColoringSetF(MatFDColoring fd,Vec F)
12: {
14: fd->F = F;
15: return(0);
16: }
20: static PetscErrorCode MatFDColoringView_Draw_Zoom(PetscDraw draw,void *Aa)
21: {
22: MatFDColoring fd = (MatFDColoring)Aa;
24: PetscInt i,j;
25: PetscReal x,y;
29: /* loop over colors */
30: for (i=0; i<fd->ncolors; i++) {
31: for (j=0; j<fd->nrows[i]; j++) {
32: y = fd->M - fd->rows[i][j] - fd->rstart;
33: x = fd->columnsforrow[i][j];
34: PetscDrawRectangle(draw,x,y,x+1,y+1,i+1,i+1,i+1,i+1);
35: }
36: }
37: return(0);
38: }
42: static PetscErrorCode MatFDColoringView_Draw(MatFDColoring fd,PetscViewer viewer)
43: {
45: PetscBool isnull;
46: PetscDraw draw;
47: PetscReal xr,yr,xl,yl,h,w;
50: PetscViewerDrawGetDraw(viewer,0,&draw);
51: PetscDrawIsNull(draw,&isnull); if (isnull) return(0);
53: PetscObjectCompose((PetscObject)fd,"Zoomviewer",(PetscObject)viewer);
55: xr = fd->N; yr = fd->M; h = yr/10.0; w = xr/10.0;
56: xr += w; yr += h; xl = -w; yl = -h;
57: PetscDrawSetCoordinates(draw,xl,yl,xr,yr);
58: PetscDrawZoom(draw,MatFDColoringView_Draw_Zoom,fd);
59: PetscObjectCompose((PetscObject)fd,"Zoomviewer",PETSC_NULL);
60: return(0);
61: }
65: /*@C
66: MatFDColoringView - Views a finite difference coloring context.
68: Collective on MatFDColoring
70: Input Parameters:
71: + c - the coloring context
72: - viewer - visualization context
74: Level: intermediate
76: Notes:
77: The available visualization contexts include
78: + PETSC_VIEWER_STDOUT_SELF - standard output (default)
79: . PETSC_VIEWER_STDOUT_WORLD - synchronized standard
80: output where only the first processor opens
81: the file. All other processors send their
82: data to the first processor to print.
83: - PETSC_VIEWER_DRAW_WORLD - graphical display of nonzero structure
85: Notes:
86: Since PETSc uses only a small number of basic colors (currently 33), if the coloring
87: involves more than 33 then some seemingly identical colors are displayed making it look
88: like an illegal coloring. This is just a graphical artifact.
90: .seealso: MatFDColoringCreate()
92: .keywords: Mat, finite differences, coloring, view
93: @*/
94: PetscErrorCode MatFDColoringView(MatFDColoring c,PetscViewer viewer)
95: {
96: PetscErrorCode ierr;
97: PetscInt i,j;
98: PetscBool isdraw,iascii;
99: PetscViewerFormat format;
103: if (!viewer) {
104: PetscViewerASCIIGetStdout(((PetscObject)c)->comm,&viewer);
105: }
109: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
110: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
111: if (isdraw) {
112: MatFDColoringView_Draw(c,viewer);
113: } else if (iascii) {
114: PetscObjectPrintClassNamePrefixType((PetscObject)c,viewer,"MatFDColoring Object");
115: PetscViewerASCIIPrintf(viewer," Error tolerance=%G\n",c->error_rel);
116: PetscViewerASCIIPrintf(viewer," Umin=%G\n",c->umin);
117: PetscViewerASCIIPrintf(viewer," Number of colors=%D\n",c->ncolors);
119: PetscViewerGetFormat(viewer,&format);
120: if (format != PETSC_VIEWER_ASCII_INFO) {
121: for (i=0; i<c->ncolors; i++) {
122: PetscViewerASCIIPrintf(viewer," Information for color %D\n",i);
123: PetscViewerASCIIPrintf(viewer," Number of columns %D\n",c->ncolumns[i]);
124: for (j=0; j<c->ncolumns[i]; j++) {
125: PetscViewerASCIIPrintf(viewer," %D\n",c->columns[i][j]);
126: }
127: PetscViewerASCIIPrintf(viewer," Number of rows %D\n",c->nrows[i]);
128: for (j=0; j<c->nrows[i]; j++) {
129: PetscViewerASCIIPrintf(viewer," %D %D \n",c->rows[i][j],c->columnsforrow[i][j]);
130: }
131: }
132: }
133: PetscViewerFlush(viewer);
134: } else {
135: SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"Viewer type %s not supported for MatFDColoring",((PetscObject)viewer)->type_name);
136: }
137: return(0);
138: }
142: /*@
143: MatFDColoringSetParameters - Sets the parameters for the sparse approximation of
144: a Jacobian matrix using finite differences.
146: Logically Collective on MatFDColoring
148: The Jacobian is estimated with the differencing approximation
149: .vb
150: F'(u)_{:,i} = [F(u+h*dx_{i}) - F(u)]/h where
151: h = error_rel*u[i] if abs(u[i]) > umin
152: = +/- error_rel*umin otherwise, with +/- determined by the sign of u[i]
153: dx_{i} = (0, ... 1, .... 0)
154: .ve
156: Input Parameters:
157: + coloring - the coloring context
158: . error_rel - relative error
159: - umin - minimum allowable u-value magnitude
161: Level: advanced
163: .keywords: Mat, finite differences, coloring, set, parameters
165: .seealso: MatFDColoringCreate(), MatFDColoringSetFromOptions()
167: @*/
168: PetscErrorCode MatFDColoringSetParameters(MatFDColoring matfd,PetscReal error,PetscReal umin)
169: {
174: if (error != PETSC_DEFAULT) matfd->error_rel = error;
175: if (umin != PETSC_DEFAULT) matfd->umin = umin;
176: return(0);
177: }
183: /*@C
184: MatFDColoringGetFunction - Gets the function to use for computing the Jacobian.
186: Not Collective
188: Input Parameters:
189: . coloring - the coloring context
191: Output Parameters:
192: + f - the function
193: - fctx - the optional user-defined function context
195: Level: intermediate
197: .keywords: Mat, Jacobian, finite differences, set, function
199: .seealso: MatFDColoringCreate(), MatFDColoringSetFunction(), MatFDColoringSetFromOptions()
201: @*/
202: PetscErrorCode MatFDColoringGetFunction(MatFDColoring matfd,PetscErrorCode (**f)(void),void **fctx)
203: {
206: if (f) *f = matfd->f;
207: if (fctx) *fctx = matfd->fctx;
208: return(0);
209: }
213: /*@C
214: MatFDColoringSetFunction - Sets the function to use for computing the Jacobian.
216: Logically Collective on MatFDColoring
218: Input Parameters:
219: + coloring - the coloring context
220: . f - the function
221: - fctx - the optional user-defined function context
223: Calling sequence of (*f) function:
224: For SNES: PetscErrorCode (*f)(SNES,Vec,Vec,void*)
225: If not using SNES: PetscErrorCode (*f)(void *dummy,Vec,Vec,void*) and dummy is ignored
227: Level: advanced
229: Notes: This function is usually used automatically by SNES (when one uses SNESSetJacobian() with the argument
230: SNESDefaultComputeJacobianColor()) and only needs to be used by someone computing a matrix via coloring directly by
231: calling MatFDColoringApply()
233: Fortran Notes:
234: In Fortran you must call MatFDColoringSetFunction() for a coloring object to
235: be used without SNES or within the SNES solvers.
237: .keywords: Mat, Jacobian, finite differences, set, function
239: .seealso: MatFDColoringCreate(), MatFDColoringGetFunction(), MatFDColoringSetFromOptions()
241: @*/
242: PetscErrorCode MatFDColoringSetFunction(MatFDColoring matfd,PetscErrorCode (*f)(void),void *fctx)
243: {
246: matfd->f = f;
247: matfd->fctx = fctx;
248: return(0);
249: }
253: /*@
254: MatFDColoringSetFromOptions - Sets coloring finite difference parameters from
255: the options database.
257: Collective on MatFDColoring
259: The Jacobian, F'(u), is estimated with the differencing approximation
260: .vb
261: F'(u)_{:,i} = [F(u+h*dx_{i}) - F(u)]/h where
262: h = error_rel*u[i] if abs(u[i]) > umin
263: = +/- error_rel*umin otherwise, with +/- determined by the sign of u[i]
264: dx_{i} = (0, ... 1, .... 0)
265: .ve
267: Input Parameter:
268: . coloring - the coloring context
270: Options Database Keys:
271: + -mat_fd_coloring_err <err> - Sets <err> (square root
272: of relative error in the function)
273: . -mat_fd_coloring_umin <umin> - Sets umin, the minimum allowable u-value magnitude
274: . -mat_fd_type - "wp" or "ds" (see MATMFFD_WP or MATMFFD_DS)
275: . -mat_fd_coloring_view - Activates basic viewing
276: . -mat_fd_coloring_view_info - Activates viewing info
277: - -mat_fd_coloring_view_draw - Activates drawing
279: Level: intermediate
281: .keywords: Mat, finite differences, parameters
283: .seealso: MatFDColoringCreate(), MatFDColoringView(), MatFDColoringSetParameters()
285: @*/
286: PetscErrorCode MatFDColoringSetFromOptions(MatFDColoring matfd)
287: {
289: PetscBool flg;
290: char value[3];
295: PetscObjectOptionsBegin((PetscObject)matfd);
296: PetscOptionsReal("-mat_fd_coloring_err","Square root of relative error in function","MatFDColoringSetParameters",matfd->error_rel,&matfd->error_rel,0);
297: PetscOptionsReal("-mat_fd_coloring_umin","Minimum allowable u magnitude","MatFDColoringSetParameters",matfd->umin,&matfd->umin,0);
298: PetscOptionsString("-mat_fd_type","Algorithm to compute h, wp or ds","MatFDColoringCreate",matfd->htype,value,3,&flg);
299: if (flg) {
300: if (value[0] == 'w' && value[1] == 'p') matfd->htype = "wp";
301: else if (value[0] == 'd' && value[1] == 's') matfd->htype = "ds";
302: else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Unknown finite differencing type %s",value);
303: }
304: /* not used here; but so they are presented in the GUI */
305: PetscOptionsName("-mat_fd_coloring_view","Print entire datastructure used for Jacobian","None",0);
306: PetscOptionsName("-mat_fd_coloring_view_info","Print number of colors etc for Jacobian","None",0);
307: PetscOptionsName("-mat_fd_coloring_view_draw","Plot nonzero structure ofJacobian","None",0);
309: /* process any options handlers added with PetscObjectAddOptionsHandler() */
310: PetscObjectProcessOptionsHandlers((PetscObject)matfd);
311: PetscOptionsEnd();
312: return(0);
313: }
317: PetscErrorCode MatFDColoringView_Private(MatFDColoring fd)
318: {
320: PetscBool flg = PETSC_FALSE;
321: PetscViewer viewer;
324: PetscViewerASCIIGetStdout(((PetscObject)fd)->comm,&viewer);
325: PetscOptionsGetBool(PETSC_NULL,"-mat_fd_coloring_view",&flg,PETSC_NULL);
326: if (flg) {
327: MatFDColoringView(fd,viewer);
328: }
329: flg = PETSC_FALSE;
330: PetscOptionsGetBool(PETSC_NULL,"-mat_fd_coloring_view_info",&flg,PETSC_NULL);
331: if (flg) {
332: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO);
333: MatFDColoringView(fd,viewer);
334: PetscViewerPopFormat(viewer);
335: }
336: flg = PETSC_FALSE;
337: PetscOptionsGetBool(PETSC_NULL,"-mat_fd_coloring_view_draw",&flg,PETSC_NULL);
338: if (flg) {
339: MatFDColoringView(fd,PETSC_VIEWER_DRAW_(((PetscObject)fd)->comm));
340: PetscViewerFlush(PETSC_VIEWER_DRAW_(((PetscObject)fd)->comm));
341: }
342: return(0);
343: }
347: /*@
348: MatFDColoringCreate - Creates a matrix coloring context for finite difference
349: computation of Jacobians.
351: Collective on Mat
353: Input Parameters:
354: + mat - the matrix containing the nonzero structure of the Jacobian
355: - iscoloring - the coloring of the matrix; usually obtained with MatGetColoring() or DMCreateColoring()
357: Output Parameter:
358: . color - the new coloring context
359:
360: Level: intermediate
362: .seealso: MatFDColoringDestroy(),SNESDefaultComputeJacobianColor(), ISColoringCreate(),
363: MatFDColoringSetFunction(), MatFDColoringSetFromOptions(), MatFDColoringApply(),
364: MatFDColoringView(), MatFDColoringSetParameters(), MatGetColoring(), DMCreateColoring()
365: @*/
366: PetscErrorCode MatFDColoringCreate(Mat mat,ISColoring iscoloring,MatFDColoring *color)
367: {
368: MatFDColoring c;
369: MPI_Comm comm;
371: PetscInt M,N;
374: PetscLogEventBegin(MAT_FDColoringCreate,mat,0,0,0);
375: MatGetSize(mat,&M,&N);
376: if (M != N) SETERRQ(((PetscObject)mat)->comm,PETSC_ERR_SUP,"Only for square matrices");
378: PetscObjectGetComm((PetscObject)mat,&comm);
379: PetscHeaderCreate(c,_p_MatFDColoring,int,MAT_FDCOLORING_CLASSID,0,"MatFDColoring","Jacobian computation via finite differences with coloring","Mat",comm,MatFDColoringDestroy,MatFDColoringView);
381: c->ctype = iscoloring->ctype;
383: if (mat->ops->fdcoloringcreate) {
384: (*mat->ops->fdcoloringcreate)(mat,iscoloring,c);
385: } else SETERRQ1(((PetscObject)mat)->comm,PETSC_ERR_SUP,"Code not yet written for matrix type %s",((PetscObject)mat)->type_name);
387: MatGetVecs(mat,PETSC_NULL,&c->w1);
388: PetscLogObjectParent(c,c->w1);
389: VecDuplicate(c->w1,&c->w2);
390: PetscLogObjectParent(c,c->w2);
392: c->error_rel = PETSC_SQRT_MACHINE_EPSILON;
393: c->umin = 100.0*PETSC_SQRT_MACHINE_EPSILON;
394: c->currentcolor = -1;
395: c->htype = "wp";
397: *color = c;
398: PetscLogEventEnd(MAT_FDColoringCreate,mat,0,0,0);
399: return(0);
400: }
404: /*@
405: MatFDColoringDestroy - Destroys a matrix coloring context that was created
406: via MatFDColoringCreate().
408: Collective on MatFDColoring
410: Input Parameter:
411: . c - coloring context
413: Level: intermediate
415: .seealso: MatFDColoringCreate()
416: @*/
417: PetscErrorCode MatFDColoringDestroy(MatFDColoring *c)
418: {
420: PetscInt i;
423: if (!*c) return(0);
424: if (--((PetscObject)(*c))->refct > 0) {*c = 0; return(0);}
426: for (i=0; i<(*c)->ncolors; i++) {
427: PetscFree((*c)->columns[i]);
428: PetscFree((*c)->rows[i]);
429: PetscFree((*c)->columnsforrow[i]);
430: if ((*c)->vscaleforrow) {PetscFree((*c)->vscaleforrow[i]);}
431: }
432: PetscFree((*c)->ncolumns);
433: PetscFree((*c)->columns);
434: PetscFree((*c)->nrows);
435: PetscFree((*c)->rows);
436: PetscFree((*c)->columnsforrow);
437: PetscFree((*c)->vscaleforrow);
438: VecDestroy(&(*c)->vscale);
439: VecDestroy(&(*c)->w1);
440: VecDestroy(&(*c)->w2);
441: VecDestroy(&(*c)->w3);
442: PetscHeaderDestroy(c);
443: return(0);
444: }
448: /*@C
449: MatFDColoringGetPerturbedColumns - Returns the indices of the columns that
450: that are currently being perturbed.
452: Not Collective
454: Input Parameters:
455: . coloring - coloring context created with MatFDColoringCreate()
457: Output Parameters:
458: + n - the number of local columns being perturbed
459: - cols - the column indices, in global numbering
461: Level: intermediate
463: .seealso: MatFDColoringCreate(), MatFDColoringDestroy(), MatFDColoringView(), MatFDColoringApply()
465: .keywords: coloring, Jacobian, finite differences
466: @*/
467: PetscErrorCode MatFDColoringGetPerturbedColumns(MatFDColoring coloring,PetscInt *n,PetscInt *cols[])
468: {
470: if (coloring->currentcolor >= 0) {
471: *n = coloring->ncolumns[coloring->currentcolor];
472: *cols = coloring->columns[coloring->currentcolor];
473: } else {
474: *n = 0;
475: }
476: return(0);
477: }
481: /*@
482: MatFDColoringApply - Given a matrix for which a MatFDColoring context
483: has been created, computes the Jacobian for a function via finite differences.
485: Collective on MatFDColoring
487: Input Parameters:
488: + mat - location to store Jacobian
489: . coloring - coloring context created with MatFDColoringCreate()
490: . x1 - location at which Jacobian is to be computed
491: - sctx - context required by function, if this is being used with the SNES solver then it is SNES object, otherwise it is null
493: Options Database Keys:
494: + -mat_fd_type - "wp" or "ds" (see MATMFFD_WP or MATMFFD_DS)
495: . -mat_fd_coloring_view - Activates basic viewing or coloring
496: . -mat_fd_coloring_view_draw - Activates drawing of coloring
497: - -mat_fd_coloring_view_info - Activates viewing of coloring info
499: Level: intermediate
501: .seealso: MatFDColoringCreate(), MatFDColoringDestroy(), MatFDColoringView(), MatFDColoringSetFunction()
503: .keywords: coloring, Jacobian, finite differences
504: @*/
505: PetscErrorCode MatFDColoringApply(Mat J,MatFDColoring coloring,Vec x1,MatStructure *flag,void *sctx)
506: {
513: if (!coloring->f) SETERRQ(((PetscObject)J)->comm,PETSC_ERR_ARG_WRONGSTATE,"Must call MatFDColoringSetFunction()");
514: if (!J->ops->fdcoloringapply) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"Not supported for this matrix type %s",((PetscObject)J)->type_name);
515: (*J->ops->fdcoloringapply)(J,coloring,x1,flag,sctx);
516: return(0);
517: }
521: PetscErrorCode MatFDColoringApply_AIJ(Mat J,MatFDColoring coloring,Vec x1,MatStructure *flag,void *sctx)
522: {
523: PetscErrorCode (*f)(void*,Vec,Vec,void*) = (PetscErrorCode (*)(void*,Vec,Vec,void *))coloring->f;
525: PetscInt k,start,end,l,row,col,srow,**vscaleforrow,m1,m2;
526: PetscScalar dx,*y,*xx,*w3_array;
527: PetscScalar *vscale_array;
528: PetscReal epsilon = coloring->error_rel,umin = coloring->umin,unorm;
529: Vec w1=coloring->w1,w2=coloring->w2,w3;
530: void *fctx = coloring->fctx;
531: PetscBool flg = PETSC_FALSE;
532: PetscInt ctype=coloring->ctype,N,col_start=0,col_end=0;
533: Vec x1_tmp;
539: if (!f) SETERRQ(((PetscObject)J)->comm,PETSC_ERR_ARG_WRONGSTATE,"Must call MatFDColoringSetFunction()");
541: PetscLogEventBegin(MAT_FDColoringApply,coloring,J,x1,0);
542: MatSetUnfactored(J);
543: PetscOptionsGetBool(PETSC_NULL,"-mat_fd_coloring_dont_rezero",&flg,PETSC_NULL);
544: if (flg) {
545: PetscInfo(coloring,"Not calling MatZeroEntries()\n");
546: } else {
547: PetscBool assembled;
548: MatAssembled(J,&assembled);
549: if (assembled) {
550: MatZeroEntries(J);
551: }
552: }
554: x1_tmp = x1;
555: if (!coloring->vscale){
556: VecDuplicate(x1_tmp,&coloring->vscale);
557: }
558:
559: /*
560: This is a horrible, horrible, hack.
561: */
562: if (coloring->F) {
563: VecGetLocalSize(coloring->F,&m1);
564: VecGetLocalSize(w1,&m2);
565: if (m1 != m2) {
566: coloring->F = 0;
567: }
568: }
570: if (coloring->htype[0] == 'w') { /* tacky test; need to make systematic if we add other approaches to computing h*/
571: VecNorm(x1_tmp,NORM_2,&unorm);
572: }
573: VecGetOwnershipRange(w1,&start,&end); /* OwnershipRange is used by ghosted x! */
574:
575: /* Set w1 = F(x1) */
576: if (coloring->F) {
577: w1 = coloring->F; /* use already computed value of function */
578: coloring->F = 0;
579: } else {
580: PetscLogEventBegin(MAT_FDColoringFunction,0,0,0,0);
581: (*f)(sctx,x1_tmp,w1,fctx);
582: PetscLogEventEnd(MAT_FDColoringFunction,0,0,0,0);
583: }
584:
585: if (!coloring->w3) {
586: VecDuplicate(x1_tmp,&coloring->w3);
587: PetscLogObjectParent(coloring,coloring->w3);
588: }
589: w3 = coloring->w3;
591: /* Compute all the local scale factors, including ghost points */
592: VecGetLocalSize(x1_tmp,&N);
593: VecGetArray(x1_tmp,&xx);
594: VecGetArray(coloring->vscale,&vscale_array);
595: if (ctype == IS_COLORING_GHOSTED){
596: col_start = 0; col_end = N;
597: } else if (ctype == IS_COLORING_GLOBAL){
598: xx = xx - start;
599: vscale_array = vscale_array - start;
600: col_start = start; col_end = N + start;
601: }
602: for (col=col_start; col<col_end; col++){
603: /* Loop over each local column, vscale[col] = 1./(epsilon*dx[col]) */
604: if (coloring->htype[0] == 'w') {
605: dx = 1.0 + unorm;
606: } else {
607: dx = xx[col];
608: }
609: if (dx == (PetscScalar)0.0) dx = 1.0;
610: #if !defined(PETSC_USE_COMPLEX)
611: if (dx < umin && dx >= 0.0) dx = umin;
612: else if (dx < 0.0 && dx > -umin) dx = -umin;
613: #else
614: if (PetscAbsScalar(dx) < umin && PetscRealPart(dx) >= 0.0) dx = umin;
615: else if (PetscRealPart(dx) < 0.0 && PetscAbsScalar(dx) < umin) dx = -umin;
616: #endif
617: dx *= epsilon;
618: vscale_array[col] = (PetscScalar)1.0/dx;
619: }
620: if (ctype == IS_COLORING_GLOBAL) vscale_array = vscale_array + start;
621: VecRestoreArray(coloring->vscale,&vscale_array);
622: if (ctype == IS_COLORING_GLOBAL){
623: VecGhostUpdateBegin(coloring->vscale,INSERT_VALUES,SCATTER_FORWARD);
624: VecGhostUpdateEnd(coloring->vscale,INSERT_VALUES,SCATTER_FORWARD);
625: }
626:
627: if (coloring->vscaleforrow) {
628: vscaleforrow = coloring->vscaleforrow;
629: } else SETERRQ(((PetscObject)J)->comm,PETSC_ERR_ARG_NULL,"Null Object: coloring->vscaleforrow");
631: /*
632: Loop over each color
633: */
634: VecGetArray(coloring->vscale,&vscale_array);
635: for (k=0; k<coloring->ncolors; k++) {
636: coloring->currentcolor = k;
637: VecCopy(x1_tmp,w3);
638: VecGetArray(w3,&w3_array);
639: if (ctype == IS_COLORING_GLOBAL) w3_array = w3_array - start;
640: /*
641: Loop over each column associated with color
642: adding the perturbation to the vector w3.
643: */
644: for (l=0; l<coloring->ncolumns[k]; l++) {
645: col = coloring->columns[k][l]; /* local column of the matrix we are probing for */
646: if (coloring->htype[0] == 'w') {
647: dx = 1.0 + unorm;
648: } else {
649: dx = xx[col];
650: }
651: if (dx == (PetscScalar)0.0) dx = 1.0;
652: #if !defined(PETSC_USE_COMPLEX)
653: if (dx < umin && dx >= 0.0) dx = umin;
654: else if (dx < 0.0 && dx > -umin) dx = -umin;
655: #else
656: if (PetscAbsScalar(dx) < umin && PetscRealPart(dx) >= 0.0) dx = umin;
657: else if (PetscRealPart(dx) < 0.0 && PetscAbsScalar(dx) < umin) dx = -umin;
658: #endif
659: dx *= epsilon;
660: if (!PetscAbsScalar(dx)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Computed 0 differencing parameter");
661: w3_array[col] += dx;
662: }
663: if (ctype == IS_COLORING_GLOBAL) w3_array = w3_array + start;
664: VecRestoreArray(w3,&w3_array);
666: /*
667: Evaluate function at w3 = x1 + dx (here dx is a vector of perturbations)
668: w2 = F(x1 + dx) - F(x1)
669: */
670: PetscLogEventBegin(MAT_FDColoringFunction,0,0,0,0);
671: (*f)(sctx,w3,w2,fctx);
672: PetscLogEventEnd(MAT_FDColoringFunction,0,0,0,0);
673: VecAXPY(w2,-1.0,w1);
674:
675: /*
676: Loop over rows of vector, putting results into Jacobian matrix
677: */
678: VecGetArray(w2,&y);
679: for (l=0; l<coloring->nrows[k]; l++) {
680: row = coloring->rows[k][l]; /* local row index */
681: col = coloring->columnsforrow[k][l]; /* global column index */
682: y[row] *= vscale_array[vscaleforrow[k][l]];
683: srow = row + start;
684: MatSetValues(J,1,&srow,1,&col,y+row,INSERT_VALUES);
685: }
686: VecRestoreArray(w2,&y);
687: } /* endof for each color */
688: if (ctype == IS_COLORING_GLOBAL) xx = xx + start;
689: VecRestoreArray(coloring->vscale,&vscale_array);
690: VecRestoreArray(x1_tmp,&xx);
691:
692: coloring->currentcolor = -1;
693: MatAssemblyBegin(J,MAT_FINAL_ASSEMBLY);
694: MatAssemblyEnd(J,MAT_FINAL_ASSEMBLY);
695: PetscLogEventEnd(MAT_FDColoringApply,coloring,J,x1,0);
697: flg = PETSC_FALSE;
698: PetscOptionsGetBool(PETSC_NULL,"-mat_null_space_test",&flg,PETSC_NULL);
699: if (flg) {
700: MatNullSpaceTest(J->nullsp,J,PETSC_NULL);
701: }
702: MatFDColoringView_Private(coloring);
703: return(0);
704: }