xref: /petsc/src/ksp/pc/impls/mg/smg.c (revision ccb4e88a40f0b86eaeca07ff64c64e4de2fae686)
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   PetscErrorCode ierr;
10   PetscInt       i,l = mglevels[0]->levels;
11 
12   PetscFunctionBegin;
13   /* compute RHS on each level */
14   for (i=l-1; i>0; i--) {
15     if (mglevels[i]->eventinterprestrict) {ierr = PetscLogEventBegin(mglevels[i]->eventinterprestrict,0,0,0,0);CHKERRQ(ierr);}
16     if (!transpose) {
17       if (matapp) { ierr = MatMatRestrict(mglevels[i]->restrct,mglevels[i]->B,&mglevels[i-1]->B);CHKERRQ(ierr); }
18       else { ierr = MatRestrict(mglevels[i]->restrct,mglevels[i]->b,mglevels[i-1]->b);CHKERRQ(ierr); }
19     } else {
20       if (matapp) { ierr = MatMatRestrict(mglevels[i]->interpolate,mglevels[i]->B,&mglevels[i-1]->B);CHKERRQ(ierr); }
21       else { ierr = MatRestrict(mglevels[i]->interpolate,mglevels[i]->b,mglevels[i-1]->b);CHKERRQ(ierr); }
22     }
23     if (mglevels[i]->eventinterprestrict) {ierr = PetscLogEventEnd(mglevels[i]->eventinterprestrict,0,0,0,0);CHKERRQ(ierr);}
24   }
25   /* solve separately on each level */
26   for (i=0; i<l; i++) {
27     if (matapp) {
28       if (!mglevels[i]->X) {
29         ierr = MatDuplicate(mglevels[i]->B,MAT_DO_NOT_COPY_VALUES,&mglevels[i]->X);CHKERRQ(ierr);
30       } else {
31         ierr = MatZeroEntries(mglevels[i]->X);CHKERRQ(ierr);
32       }
33     } else {
34       ierr = VecZeroEntries(mglevels[i]->x);CHKERRQ(ierr);
35     }
36     if (mglevels[i]->eventsmoothsolve) {ierr = PetscLogEventBegin(mglevels[i]->eventsmoothsolve,0,0,0,0);CHKERRQ(ierr);}
37     if (!transpose) {
38       if (matapp) {
39         ierr = KSPMatSolve(mglevels[i]->smoothd,mglevels[i]->B,mglevels[i]->X);CHKERRQ(ierr);
40         ierr = KSPCheckSolve(mglevels[i]->smoothd,pc,NULL);CHKERRQ(ierr);
41       } else {
42         ierr = KSPSolve(mglevels[i]->smoothd,mglevels[i]->b,mglevels[i]->x);CHKERRQ(ierr);
43         ierr = KSPCheckSolve(mglevels[i]->smoothd,pc,mglevels[i]->x);CHKERRQ(ierr);
44       }
45     } else {
46       if (matapp) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Not supported");
47       ierr = KSPSolveTranspose(mglevels[i]->smoothu,mglevels[i]->b,mglevels[i]->x);CHKERRQ(ierr);
48       ierr = KSPCheckSolve(mglevels[i]->smoothu,pc,mglevels[i]->x);CHKERRQ(ierr);
49     }
50     if (mglevels[i]->eventsmoothsolve) {ierr = PetscLogEventEnd(mglevels[i]->eventsmoothsolve,0,0,0,0);CHKERRQ(ierr);}
51   }
52   for (i=1; i<l; i++) {
53     if (mglevels[i]->eventinterprestrict) {ierr = PetscLogEventBegin(mglevels[i]->eventinterprestrict,0,0,0,0);CHKERRQ(ierr);}
54     if (!transpose) {
55       if (matapp) { ierr = MatMatInterpolateAdd(mglevels[i]->interpolate,mglevels[i-1]->X,mglevels[i]->X,&mglevels[i]->X);CHKERRQ(ierr); }
56       else { ierr = MatInterpolateAdd(mglevels[i]->interpolate,mglevels[i-1]->x,mglevels[i]->x,mglevels[i]->x);CHKERRQ(ierr); }
57     } else {
58       if (matapp) { ierr = MatMatInterpolateAdd(mglevels[i]->restrct,mglevels[i-1]->X,mglevels[i]->X,&mglevels[i]->X);CHKERRQ(ierr); }
59       else { ierr = MatInterpolateAdd(mglevels[i]->restrct,mglevels[i-1]->x,mglevels[i]->x,mglevels[i]->x);CHKERRQ(ierr); }
60     }
61     if (mglevels[i]->eventinterprestrict) {ierr = PetscLogEventEnd(mglevels[i]->eventinterprestrict,0,0,0,0);CHKERRQ(ierr);}
62   }
63   PetscFunctionReturn(0);
64 }
65