xref: /petsc/src/ksp/pc/impls/mg/fmg.c (revision 21e3ffae2f3b73c0bd738cf6d0a809700fc04bb0)
1 /*
2      Full multigrid using either additive or multiplicative V or W cycle
3 */
4 #include <petsc/private/pcmgimpl.h>
5 
6 PetscErrorCode PCMGFCycle_Private(PC pc, PC_MG_Levels **mglevels, PetscBool transpose, PetscBool matapp)
7 {
8   PetscInt i, l = mglevels[0]->levels;
9 
10   PetscFunctionBegin;
11   if (!transpose) {
12     /* restrict the RHS through all levels to coarsest. */
13     for (i = l - 1; i > 0; i--) {
14       if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels[i]->eventinterprestrict, 0, 0, 0, 0));
15       if (matapp) PetscCall(MatMatRestrict(mglevels[i]->restrct, mglevels[i]->B, &mglevels[i - 1]->B));
16       else PetscCall(MatRestrict(mglevels[i]->restrct, mglevels[i]->b, mglevels[i - 1]->b));
17       if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels[i]->eventinterprestrict, 0, 0, 0, 0));
18     }
19 
20     /* work our way up through the levels */
21     if (matapp) {
22       if (!mglevels[0]->X) {
23         PetscCall(MatDuplicate(mglevels[0]->B, MAT_DO_NOT_COPY_VALUES, &mglevels[0]->X));
24       } else {
25         PetscCall(MatZeroEntries(mglevels[0]->X));
26       }
27     } else {
28       PetscCall(VecZeroEntries(mglevels[0]->x));
29     }
30     for (i = 0; i < l - 1; i++) {
31       PetscCall(PCMGMCycle_Private(pc, &mglevels[i], transpose, matapp, NULL));
32       if (mglevels[i + 1]->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels[i + 1]->eventinterprestrict, 0, 0, 0, 0));
33       if (matapp) PetscCall(MatMatInterpolate(mglevels[i + 1]->interpolate, mglevels[i]->X, &mglevels[i + 1]->X));
34       else PetscCall(MatInterpolate(mglevels[i + 1]->interpolate, mglevels[i]->x, mglevels[i + 1]->x));
35       if (mglevels[i + 1]->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels[i + 1]->eventinterprestrict, 0, 0, 0, 0));
36     }
37     PetscCall(PCMGMCycle_Private(pc, &mglevels[l - 1], transpose, matapp, NULL));
38   } else {
39     PetscCall(PCMGMCycle_Private(pc, &mglevels[l - 1], transpose, matapp, NULL));
40     for (i = l - 2; i >= 0; i--) {
41       if (mglevels[i + 1]->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels[i + 1]->eventinterprestrict, 0, 0, 0, 0));
42       if (matapp) PetscCall(MatMatRestrict(mglevels[i + 1]->interpolate, mglevels[i + 1]->X, &mglevels[i]->X));
43       else PetscCall(MatRestrict(mglevels[i + 1]->interpolate, mglevels[i + 1]->x, mglevels[i]->x));
44       if (mglevels[i + 1]->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels[i + 1]->eventinterprestrict, 0, 0, 0, 0));
45       PetscCall(PCMGMCycle_Private(pc, &mglevels[i], transpose, matapp, NULL));
46     }
47     for (i = 1; i < l; i++) {
48       if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels[i]->eventinterprestrict, 0, 0, 0, 0));
49       if (matapp) PetscCall(MatMatInterpolate(mglevels[i]->restrct, mglevels[i - 1]->B, &mglevels[i]->B));
50       else PetscCall(MatInterpolate(mglevels[i]->restrct, mglevels[i - 1]->b, mglevels[i]->b));
51       if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels[i]->eventinterprestrict, 0, 0, 0, 0));
52     }
53   }
54   PetscFunctionReturn(PETSC_SUCCESS);
55 }
56 
57 PetscErrorCode PCMGKCycle_Private(PC pc, PC_MG_Levels **mglevels, PetscBool transpose, PetscBool matapp)
58 {
59   PetscInt i, l = mglevels[0]->levels;
60 
61   PetscFunctionBegin;
62   /* restrict the RHS through all levels to coarsest. */
63   for (i = l - 1; i > 0; i--) {
64     if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels[i]->eventinterprestrict, 0, 0, 0, 0));
65     if (matapp) PetscCall(MatMatRestrict(mglevels[i]->restrct, mglevels[i]->B, &mglevels[i - 1]->B));
66     else PetscCall(MatRestrict(mglevels[i]->restrct, mglevels[i]->b, mglevels[i - 1]->b));
67     if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels[i]->eventinterprestrict, 0, 0, 0, 0));
68   }
69 
70   /* work our way up through the levels */
71   if (matapp) {
72     if (!mglevels[0]->X) {
73       PetscCall(MatDuplicate(mglevels[0]->B, MAT_DO_NOT_COPY_VALUES, &mglevels[0]->X));
74     } else {
75       PetscCall(MatZeroEntries(mglevels[0]->X));
76     }
77   } else {
78     PetscCall(VecZeroEntries(mglevels[0]->x));
79   }
80   for (i = 0; i < l - 1; i++) {
81     if (mglevels[i]->eventsmoothsolve) PetscCall(PetscLogEventBegin(mglevels[i]->eventsmoothsolve, 0, 0, 0, 0));
82     if (matapp) {
83       PetscCall(KSPMatSolve(mglevels[i]->smoothd, mglevels[i]->B, mglevels[i]->X));
84       PetscCall(KSPCheckSolve(mglevels[i]->smoothd, pc, NULL));
85     } else {
86       PetscCall(KSPSolve(mglevels[i]->smoothd, mglevels[i]->b, mglevels[i]->x));
87       PetscCall(KSPCheckSolve(mglevels[i]->smoothd, pc, mglevels[i]->x));
88     }
89     if (mglevels[i]->eventsmoothsolve) PetscCall(PetscLogEventEnd(mglevels[i]->eventsmoothsolve, 0, 0, 0, 0));
90     if (mglevels[i + 1]->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels[i + 1]->eventinterprestrict, 0, 0, 0, 0));
91     if (matapp) PetscCall(MatMatInterpolate(mglevels[i + 1]->interpolate, mglevels[i]->X, &mglevels[i + 1]->X));
92     else PetscCall(MatInterpolate(mglevels[i + 1]->interpolate, mglevels[i]->x, mglevels[i + 1]->x));
93     if (mglevels[i + 1]->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels[i + 1]->eventinterprestrict, 0, 0, 0, 0));
94   }
95   if (mglevels[l - 1]->eventsmoothsolve) PetscCall(PetscLogEventBegin(mglevels[l - 1]->eventsmoothsolve, 0, 0, 0, 0));
96   if (matapp) {
97     PetscCall(KSPMatSolve(mglevels[l - 1]->smoothd, mglevels[l - 1]->B, mglevels[l - 1]->X));
98     PetscCall(KSPCheckSolve(mglevels[l - 1]->smoothd, pc, NULL));
99   } else {
100     PetscCall(KSPSolve(mglevels[l - 1]->smoothd, mglevels[l - 1]->b, mglevels[l - 1]->x));
101     PetscCall(KSPCheckSolve(mglevels[l - 1]->smoothd, pc, mglevels[l - 1]->x));
102   }
103   if (mglevels[l - 1]->eventsmoothsolve) PetscCall(PetscLogEventEnd(mglevels[l - 1]->eventsmoothsolve, 0, 0, 0, 0));
104   PetscFunctionReturn(PETSC_SUCCESS);
105 }
106