1: /*
  2:      Additive Multigrid V Cycle routine
  3: */
  4: #include <petsc/private/pcmgimpl.h>

  6: PetscErrorCode PCMGACycle_Private(PC pc, PC_MG_Levels **mglevels, PetscBool transpose, PetscBool matapp)
  7: {
  8:   PetscInt i, l = mglevels[0]->levels;

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