xref: /petsc/src/snes/impls/gs/gssecant.c (revision df6f6c19b095f1abc1ac27fcbb9c2092a4a2a65e)
1 #include <../src/snes/impls/gs/gsimpl.h>
2 
3 #undef __FUNCT__
4 #define __FUNCT__ "SNESNGSDestroy_Private"
5 static PetscErrorCode SNESNGSDestroy_Private(ISColoring coloring)
6 {
7   PetscErrorCode ierr;
8 
9   PetscFunctionBegin;
10   ierr = ISColoringDestroy(&coloring);CHKERRQ(ierr);
11   PetscFunctionReturn(0);
12 }
13 
14 #undef __FUNCT__
15 #define __FUNCT__ "SNESComputeNGSDefaultSecant"
16 PETSC_EXTERN PetscErrorCode SNESComputeNGSDefaultSecant(SNES snes,Vec X,Vec B,void *ctx)
17 {
18   PetscErrorCode ierr;
19   SNES_NGS       *gs = (SNES_NGS*)snes->data;
20   PetscInt       i,j,k,ncolors;
21   DM             dm;
22   PetscBool      flg;
23   ISColoring     coloring;
24   MatColoring    mc;
25   Vec            W,G,F;
26   PetscScalar    h=gs->h;
27   IS             *coloris;
28   PetscScalar    f,g,x,w,d;
29   PetscReal      dxt,xt,ft,ft1=0;
30   const PetscInt *idx;
31   PetscInt       size,s;
32   PetscReal      atol,rtol,stol;
33   PetscInt       its;
34   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
35   void           *fctx;
36   PetscContainer colorcontainer;
37   PetscBool      mat = gs->secant_mat,equal,isdone,alldone;
38   PetscScalar    *xa,*fa,*wa,*ga;
39 
40   PetscFunctionBegin;
41   if (snes->nwork < 3) {
42     ierr = SNESSetWorkVecs(snes,3);CHKERRQ(ierr);
43   }
44   W = snes->work[0];
45   G = snes->work[1];
46   F = snes->work[2];
47   ierr = VecGetOwnershipRange(X,&s,NULL);CHKERRQ(ierr);
48   ierr = SNESNGSGetTolerances(snes,&atol,&rtol,&stol,&its);CHKERRQ(ierr);
49   ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr);
50   ierr = SNESGetFunction(snes,NULL,&func,&fctx);CHKERRQ(ierr);
51   ierr = PetscObjectQuery((PetscObject)snes,"SNESNGSColoring",(PetscObject*)&colorcontainer);CHKERRQ(ierr);
52   if (!colorcontainer) {
53     /* create the coloring */
54     ierr = DMHasColoring(dm,&flg);CHKERRQ(ierr);
55     if (flg && !mat) {
56       ierr = DMCreateColoring(dm,IS_COLORING_GLOBAL,&coloring);CHKERRQ(ierr);
57     } else {
58       if (!snes->jacobian) {ierr = SNESSetUpMatrices(snes);CHKERRQ(ierr);}
59       ierr = MatColoringCreate(snes->jacobian,&mc);CHKERRQ(ierr);
60       ierr = MatColoringSetDistance(mc,1);CHKERRQ(ierr);
61       ierr = MatColoringSetFromOptions(mc);CHKERRQ(ierr);
62       ierr = MatColoringApply(mc,&coloring);CHKERRQ(ierr);
63       ierr = MatColoringDestroy(&mc);CHKERRQ(ierr);
64     }
65     ierr = PetscContainerCreate(PetscObjectComm((PetscObject)snes),&colorcontainer);CHKERRQ(ierr);
66     ierr = PetscContainerSetPointer(colorcontainer,(void *)coloring);CHKERRQ(ierr);
67     ierr = PetscContainerSetUserDestroy(colorcontainer,(PetscErrorCode (*)(void *))SNESNGSDestroy_Private);CHKERRQ(ierr);
68     ierr = PetscObjectCompose((PetscObject)snes,"SNESNGSColoring",(PetscObject)colorcontainer);CHKERRQ(ierr);
69     ierr = PetscContainerDestroy(&colorcontainer);CHKERRQ(ierr);
70   } else {
71     ierr = PetscContainerGetPointer(colorcontainer,(void **)&coloring);CHKERRQ(ierr);
72   }
73   ierr = ISColoringGetIS(coloring,&ncolors,&coloris);CHKERRQ(ierr);
74   ierr = VecEqual(X,snes->vec_sol,&equal);CHKERRQ(ierr);
75   if (equal && snes->normschedule == SNES_NORM_ALWAYS) {
76     /* assume that the function is already computed */
77     ierr = VecCopy(snes->vec_func,F);CHKERRQ(ierr);
78   } else {
79     ierr = PetscLogEventBegin(SNES_NGSFuncEval,snes,X,B,0);CHKERRQ(ierr);
80     ierr = (*func)(snes,X,F,fctx);CHKERRQ(ierr);
81     ierr = PetscLogEventEnd(SNES_NGSFuncEval,snes,X,B,0);CHKERRQ(ierr);
82     if (B) {ierr = VecAXPY(F,-1.0,B);CHKERRQ(ierr);}
83   }
84   ierr = VecGetArray(X,&xa);CHKERRQ(ierr);
85   ierr = VecGetArray(F,&fa);CHKERRQ(ierr);
86   ierr = VecGetArray(G,&ga);CHKERRQ(ierr);
87   ierr = VecGetArray(W,&wa);CHKERRQ(ierr);
88   for (i=0;i<ncolors;i++) {
89     ierr = ISGetIndices(coloris[i],&idx);CHKERRQ(ierr);
90     ierr = ISGetLocalSize(coloris[i],&size);CHKERRQ(ierr);
91     ierr = VecCopy(X,W);CHKERRQ(ierr);
92     for (j=0;j<size;j++) {
93       wa[idx[j]-s] += h;
94     }
95     ierr = PetscLogEventBegin(SNES_NGSFuncEval,snes,X,B,0);CHKERRQ(ierr);
96     ierr = (*func)(snes,W,G,fctx);CHKERRQ(ierr);
97     ierr = PetscLogEventEnd(SNES_NGSFuncEval,snes,X,B,0);CHKERRQ(ierr);
98     if (B) {ierr = VecAXPY(G,-1.0,B);CHKERRQ(ierr);}
99     for (k=0;k<its;k++) {
100       dxt = 0.;
101       xt = 0.;
102       ft = 0.;
103       for (j=0;j<size;j++) {
104         f = fa[idx[j]-s];
105         x = xa[idx[j]-s];
106         g = ga[idx[j]-s];
107         w = wa[idx[j]-s];
108         if (PetscAbsScalar(g-f) > atol) {
109           /* This is equivalent to d = x - (h*f) / PetscRealPart(g-f) */
110           d = (x*g-w*f) / PetscRealPart(g-f);
111         } else {
112           d = x;
113         }
114         dxt += PetscRealPart(PetscSqr(d-x));
115         xt += PetscRealPart(PetscSqr(x));
116         ft += PetscRealPart(PetscSqr(f));
117         xa[idx[j]-s] = d;
118       }
119 
120       if (k == 0) ft1 = PetscSqrtReal(ft);
121       if (k<its-1) {
122         isdone = PETSC_FALSE;
123         if (stol*PetscSqrtReal(xt) > PetscSqrtReal(dxt)) isdone = PETSC_TRUE;
124         if (PetscSqrtReal(ft) < atol) isdone = PETSC_TRUE;
125         if (rtol*ft1 > PetscSqrtReal(ft)) isdone = PETSC_TRUE;
126         ierr = MPI_Allreduce(&isdone,&alldone,1,MPIU_BOOL,MPI_BAND,PetscObjectComm((PetscObject)snes));CHKERRQ(ierr);
127         if (alldone) break;
128       }
129       if (i < ncolors-1 || k < its-1) {
130         ierr = PetscLogEventBegin(SNES_NGSFuncEval,snes,X,B,0);CHKERRQ(ierr);
131         ierr = (*func)(snes,X,F,fctx);CHKERRQ(ierr);
132         ierr = PetscLogEventEnd(SNES_NGSFuncEval,snes,X,B,0);CHKERRQ(ierr);
133         if (B) {ierr = VecAXPY(F,-1.0,B);CHKERRQ(ierr);}
134       }
135       if (k<its-1) {
136         ierr = VecSwap(X,W);CHKERRQ(ierr);
137         ierr = VecSwap(F,G);CHKERRQ(ierr);
138       }
139     }
140   }
141   ierr = VecRestoreArray(X,&xa);CHKERRQ(ierr);
142   ierr = VecRestoreArray(F,&fa);CHKERRQ(ierr);
143   ierr = VecRestoreArray(G,&ga);CHKERRQ(ierr);
144   ierr = VecRestoreArray(W,&wa);CHKERRQ(ierr);
145   ierr = ISColoringRestoreIS(coloring,&coloris);CHKERRQ(ierr);
146   PetscFunctionReturn(0);
147 }
148