xref: /petsc/src/snes/impls/gs/gssecant.c (revision ef107cf556babef7f252fee75ac80f2dee5e62ad)
1 #include <petsc-private/snesimpl.h>      /*I "petscsnes.h"  I*/
2 #include <petscdm.h>
3 
4 #undef __FUNCT__
5 #define __FUNCT__ "GSDestroy_Private"
6 PetscErrorCode GSDestroy_Private(ISColoring coloring)
7 {
8   PetscErrorCode ierr;
9 
10   PetscFunctionBegin;
11   ierr = ISColoringDestroy(&coloring);CHKERRQ(ierr);
12   PetscFunctionReturn(0);
13 
14 }
15 
16 #undef __FUNCT__
17 #define __FUNCT__ "SNESComputeGSDefaultSecant"
18 PETSC_EXTERN PetscErrorCode SNESComputeGSDefaultSecant(SNES snes,Vec X,Vec B,void *ctx)
19 {
20 
21   PetscErrorCode ierr;
22   PetscInt       i,j,k,ncolors;
23   DM             dm;
24   PetscBool      flg;
25   ISColoring     coloring;
26   MatColoring    mc;
27   Vec            W,G,F;
28   PetscScalar    h=1e-6;
29   IS             *coloris;
30   PetscScalar    f,g,x,w,d;
31   const PetscInt *idx;
32   PetscInt       size;
33   PetscReal      atol,rtol,stol;
34   PetscInt       its;
35   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
36   void           *fctx;
37   PetscContainer colorcontainer;
38 
39   PetscFunctionBegin;
40   if (snes->nwork < 3) {
41     ierr = SNESSetWorkVecs(snes,3);CHKERRQ(ierr);
42   }
43   W = snes->work[0];
44   G = snes->work[1];
45   F = snes->work[2];
46   ierr = SNESGSGetTolerances(snes,&atol,&rtol,&stol,&its);CHKERRQ(ierr);
47   ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr);
48   ierr = SNESGetFunction(snes,NULL,&func,&fctx);CHKERRQ(ierr);
49   ierr = PetscObjectQuery((PetscObject)snes,"SNESGSColoring",(PetscObject*)&colorcontainer);CHKERRQ(ierr);
50   if (!colorcontainer) {
51     /* create the coloring */
52     ierr = DMHasColoring(dm,&flg);CHKERRQ(ierr);
53     if (flg) {
54       ierr = DMCreateColoring(dm,IS_COLORING_GLOBAL,&coloring);CHKERRQ(ierr);
55     } else {
56       if (!snes->jacobian) {ierr = SNESSetUpMatrices(snes);CHKERRQ(ierr);}
57       ierr = MatColoringCreate(snes->jacobian,&mc);CHKERRQ(ierr);
58       ierr = MatColoringSetDistance(mc,1);CHKERRQ(ierr);
59       ierr = MatColoringSetFromOptions(mc);CHKERRQ(ierr);
60       ierr = MatColoringApply(mc,&coloring);CHKERRQ(ierr);
61       ierr = MatColoringDestroy(&mc);CHKERRQ(ierr);
62     }
63     ierr = PetscContainerCreate(PetscObjectComm((PetscObject)snes),&colorcontainer);CHKERRQ(ierr);
64     ierr = PetscContainerSetPointer(colorcontainer,(void *)coloring);CHKERRQ(ierr);
65     ierr = PetscContainerSetUserDestroy(colorcontainer,(PetscErrorCode (*)(void *))GSDestroy_Private);CHKERRQ(ierr);
66     ierr = PetscObjectCompose((PetscObject)snes,"SNESGSColoring",(PetscObject)colorcontainer);CHKERRQ(ierr);
67     ierr = PetscContainerDestroy(&colorcontainer);CHKERRQ(ierr);
68   } else {
69     ierr = PetscContainerGetPointer(colorcontainer,(void **)&coloring);CHKERRQ(ierr);
70   }
71   ierr = ISColoringGetIS(coloring,&ncolors,&coloris);CHKERRQ(ierr);
72   for (i=0;i<ncolors;i++) {
73     for (k=0;k<its;k++) {
74       ierr = (*func)(snes,X,F,fctx);CHKERRQ(ierr);
75       if (B) {ierr = VecAXPY(F,-1.0,B);CHKERRQ(ierr);}
76       ierr = ISGetIndices(coloris[i],&idx);CHKERRQ(ierr);
77       ierr = ISGetLocalSize(coloris[i],&size);CHKERRQ(ierr);
78       ierr = VecCopy(X,W);CHKERRQ(ierr);
79       for (j=0;j<size;j++) {
80         ierr = VecSetValue(W,idx[j],h,ADD_VALUES);CHKERRQ(ierr);
81       }
82       ierr = (*func)(snes,W,G,fctx);CHKERRQ(ierr);
83       if (B) {ierr = VecAXPY(G,-1.0,B);CHKERRQ(ierr);}
84       for (j=0;j<size;j++) {
85         ierr = VecGetValues(F,1,&idx[j],&f);CHKERRQ(ierr);
86         ierr = VecGetValues(X,1,&idx[j],&x);CHKERRQ(ierr);
87         ierr = VecGetValues(G,1,&idx[j],&g);CHKERRQ(ierr);
88         ierr = VecGetValues(W,1,&idx[j],&w);CHKERRQ(ierr);
89         d = (x*g-w*f) / PetscRealPart(g-f);
90         ierr = VecSetValue(X,idx[j],d,INSERT_VALUES);CHKERRQ(ierr);
91       }
92     }
93   }
94   ierr = ISColoringRestoreIS(coloring,&coloris);CHKERRQ(ierr);
95   PetscFunctionReturn(0);
96 }
97