xref: /petsc/src/ksp/pc/impls/mg/smg.c (revision b6d8efd844103bbe70b66cc4fbc58f90317efaeb)
1 
2 /*
3      Additive Multigrid V Cycle routine
4 */
5 #include <petsc/private/pcmgimpl.h>
6 
7 PetscErrorCode PCMGACycle_Private(PC pc, PC_MG_Levels **mglevels, PetscBool transpose, PetscBool matapp)
8 {
9   PetscInt i, l = mglevels[0]->levels;
10 
11   PetscFunctionBegin;
12   /* compute RHS on each level */
13   for (i = l - 1; i > 0; i--) {
14     if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels[i]->eventinterprestrict, 0, 0, 0, 0));
15     if (!transpose) {
16       if (matapp) PetscCall(MatMatRestrict(mglevels[i]->restrct, mglevels[i]->B, &mglevels[i - 1]->B));
17       else PetscCall(MatRestrict(mglevels[i]->restrct, mglevels[i]->b, mglevels[i - 1]->b));
18     } else {
19       if (matapp) PetscCall(MatMatRestrict(mglevels[i]->interpolate, mglevels[i]->B, &mglevels[i - 1]->B));
20       else PetscCall(MatRestrict(mglevels[i]->interpolate, mglevels[i]->b, mglevels[i - 1]->b));
21     }
22     if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels[i]->eventinterprestrict, 0, 0, 0, 0));
23   }
24   /* solve separately on each level */
25   for (i = 0; i < l; i++) {
26     if (matapp) {
27       if (!mglevels[i]->X) {
28         PetscCall(MatDuplicate(mglevels[i]->B, MAT_DO_NOT_COPY_VALUES, &mglevels[i]->X));
29       } else {
30         PetscCall(MatZeroEntries(mglevels[i]->X));
31       }
32     } else {
33       PetscCall(VecZeroEntries(mglevels[i]->x));
34     }
35     if (mglevels[i]->eventsmoothsolve) PetscCall(PetscLogEventBegin(mglevels[i]->eventsmoothsolve, 0, 0, 0, 0));
36     if (!transpose) {
37       if (matapp) {
38         PetscCall(KSPMatSolve(mglevels[i]->smoothd, mglevels[i]->B, mglevels[i]->X));
39         PetscCall(KSPCheckSolve(mglevels[i]->smoothd, pc, NULL));
40       } else {
41         PetscCall(KSPSolve(mglevels[i]->smoothd, mglevels[i]->b, mglevels[i]->x));
42         PetscCall(KSPCheckSolve(mglevels[i]->smoothd, pc, mglevels[i]->x));
43       }
44     } else {
45       PetscCheck(!matapp, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Not supported");
46       PetscCall(KSPSolveTranspose(mglevels[i]->smoothu, mglevels[i]->b, mglevels[i]->x));
47       PetscCall(KSPCheckSolve(mglevels[i]->smoothu, pc, mglevels[i]->x));
48     }
49     if (mglevels[i]->eventsmoothsolve) PetscCall(PetscLogEventEnd(mglevels[i]->eventsmoothsolve, 0, 0, 0, 0));
50   }
51   for (i = 1; i < l; i++) {
52     if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels[i]->eventinterprestrict, 0, 0, 0, 0));
53     if (!transpose) {
54       if (matapp) PetscCall(MatMatInterpolateAdd(mglevels[i]->interpolate, mglevels[i - 1]->X, mglevels[i]->X, &mglevels[i]->X));
55       else PetscCall(MatInterpolateAdd(mglevels[i]->interpolate, mglevels[i - 1]->x, mglevels[i]->x, mglevels[i]->x));
56     } else {
57       if (matapp) PetscCall(MatMatInterpolateAdd(mglevels[i]->restrct, mglevels[i - 1]->X, mglevels[i]->X, &mglevels[i]->X));
58       else PetscCall(MatInterpolateAdd(mglevels[i]->restrct, mglevels[i - 1]->x, mglevels[i]->x, mglevels[i]->x));
59     }
60     if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels[i]->eventinterprestrict, 0, 0, 0, 0));
61   }
62   PetscFunctionReturn(PETSC_SUCCESS);
63 }
64