Actual source code: fmg.c

petsc-3.15.0 2021-03-30
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  1: /*
  2:      Full multigrid using either additive or multiplicative V or W cycle
  3: */
  4: #include <petsc/private/pcmgimpl.h>

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

 12:   if (!transpose) {
 13:     /* restrict the RHS through all levels to coarsest. */
 14:     for (i=l-1; i>0; i--) {
 15:       if (mglevels[i]->eventinterprestrict) {PetscLogEventBegin(mglevels[i]->eventinterprestrict,0,0,0,0);}
 16:       if (matapp) { MatMatRestrict(mglevels[i]->restrct,mglevels[i]->B,&mglevels[i-1]->B); }
 17:       else { MatRestrict(mglevels[i]->restrct,mglevels[i]->b,mglevels[i-1]->b); }
 18:       if (mglevels[i]->eventinterprestrict) {PetscLogEventEnd(mglevels[i]->eventinterprestrict,0,0,0,0);}
 19:     }

 21:     /* work our way up through the levels */
 22:     if (matapp) {
 23:       if (!mglevels[0]->X) {
 24:         MatDuplicate(mglevels[0]->B,MAT_DO_NOT_COPY_VALUES,&mglevels[0]->X);
 25:       } else {
 26:         MatZeroEntries(mglevels[0]->X);
 27:       }
 28:     } else {
 29:       VecZeroEntries(mglevels[0]->x);
 30:     }
 31:     for (i=0; i<l-1; i++) {
 32:       PCMGMCycle_Private(pc,&mglevels[i],transpose,matapp,NULL);
 33:       if (mglevels[i+1]->eventinterprestrict) {PetscLogEventBegin(mglevels[i+1]->eventinterprestrict,0,0,0,0);}
 34:       if (matapp) { MatMatInterpolate(mglevels[i+1]->interpolate,mglevels[i]->X,&mglevels[i+1]->X); }
 35:       else { MatInterpolate(mglevels[i+1]->interpolate,mglevels[i]->x,mglevels[i+1]->x); }
 36:       if (mglevels[i+1]->eventinterprestrict) {PetscLogEventEnd(mglevels[i+1]->eventinterprestrict,0,0,0,0);}
 37:     }
 38:     PCMGMCycle_Private(pc,&mglevels[l-1],transpose,matapp,NULL);
 39:   } else {
 40:     PCMGMCycle_Private(pc,&mglevels[l-1],transpose,matapp,NULL);
 41:     for (i=l-2; i>=0; i--) {
 42:       if (mglevels[i+1]->eventinterprestrict) {PetscLogEventBegin(mglevels[i+1]->eventinterprestrict,0,0,0,0);}
 43:       if (matapp) { MatMatRestrict(mglevels[i+1]->interpolate,mglevels[i+1]->X,&mglevels[i]->X); }
 44:       else { MatRestrict(mglevels[i+1]->interpolate,mglevels[i+1]->x,mglevels[i]->x); }
 45:       if (mglevels[i+1]->eventinterprestrict) {PetscLogEventEnd(mglevels[i+1]->eventinterprestrict,0,0,0,0);}
 46:       PCMGMCycle_Private(pc,&mglevels[i],transpose,matapp,NULL);
 47:     }
 48:     for (i=1; i<l; i++) {
 49:       if (mglevels[i]->eventinterprestrict) {PetscLogEventBegin(mglevels[i]->eventinterprestrict,0,0,0,0);}
 50:       if (matapp) { MatMatInterpolate(mglevels[i]->restrct,mglevels[i-1]->B,&mglevels[i]->B); }
 51:       else { MatInterpolate(mglevels[i]->restrct,mglevels[i-1]->b,mglevels[i]->b); }
 52:       if (mglevels[i]->eventinterprestrict) {PetscLogEventEnd(mglevels[i]->eventinterprestrict,0,0,0,0);}
 53:     }
 54:   }
 55:   return(0);
 56: }

 58: PetscErrorCode PCMGKCycle_Private(PC pc,PC_MG_Levels **mglevels,PetscBool transpose,PetscBool matapp)
 59: {
 61:   PetscInt       i,l = mglevels[0]->levels;

 64:   /* restrict the RHS through all levels to coarsest. */
 65:   for (i=l-1; i>0; i--) {
 66:     if (mglevels[i]->eventinterprestrict) {PetscLogEventBegin(mglevels[i]->eventinterprestrict,0,0,0,0);}
 67:     if (matapp) { MatMatRestrict(mglevels[i]->restrct,mglevels[i]->B,&mglevels[i-1]->B); }
 68:     else { MatRestrict(mglevels[i]->restrct,mglevels[i]->b,mglevels[i-1]->b); }
 69:     if (mglevels[i]->eventinterprestrict) {PetscLogEventEnd(mglevels[i]->eventinterprestrict,0,0,0,0);}
 70:   }

 72:   /* work our way up through the levels */
 73:   if (matapp) {
 74:     if (!mglevels[0]->X) {
 75:       MatDuplicate(mglevels[0]->B,MAT_DO_NOT_COPY_VALUES,&mglevels[0]->X);
 76:     } else {
 77:       MatZeroEntries(mglevels[0]->X);
 78:     }
 79:   } else {
 80:     VecZeroEntries(mglevels[0]->x);
 81:   }
 82:   for (i=0; i<l-1; i++) {
 83:     if (mglevels[i]->eventsmoothsolve) {PetscLogEventBegin(mglevels[i]->eventsmoothsolve,0,0,0,0);}
 84:     if (matapp) {
 85:       KSPMatSolve(mglevels[i]->smoothd,mglevels[i]->B,mglevels[i]->X);
 86:       KSPCheckSolve(mglevels[i]->smoothd,pc,NULL);
 87:     } else {
 88:       KSPSolve(mglevels[i]->smoothd,mglevels[i]->b,mglevels[i]->x);
 89:       KSPCheckSolve(mglevels[i]->smoothd,pc,mglevels[i]->x);
 90:     }
 91:     if (mglevels[i]->eventsmoothsolve) {PetscLogEventEnd(mglevels[i]->eventsmoothsolve,0,0,0,0);}
 92:     if (mglevels[i+1]->eventinterprestrict) {PetscLogEventBegin(mglevels[i+1]->eventinterprestrict,0,0,0,0);}
 93:     if (matapp) { MatMatInterpolate(mglevels[i+1]->interpolate,mglevels[i]->X,&mglevels[i+1]->X); }
 94:     else { MatInterpolate(mglevels[i+1]->interpolate,mglevels[i]->x,mglevels[i+1]->x); }
 95:     if (mglevels[i+1]->eventinterprestrict) {PetscLogEventEnd(mglevels[i+1]->eventinterprestrict,0,0,0,0);}
 96:   }
 97:   if (mglevels[l-1]->eventsmoothsolve) {PetscLogEventBegin(mglevels[l-1]->eventsmoothsolve,0,0,0,0);}
 98:   if (matapp) {
 99:     KSPMatSolve(mglevels[l-1]->smoothd,mglevels[l-1]->B,mglevels[l-1]->X);
100:     KSPCheckSolve(mglevels[l-1]->smoothd,pc,NULL);
101:   } else {
102:     KSPSolve(mglevels[l-1]->smoothd,mglevels[l-1]->b,mglevels[l-1]->x);
103:     KSPCheckSolve(mglevels[l-1]->smoothd,pc,mglevels[l-1]->x);
104:   }
105:   if (mglevels[l-1]->eventsmoothsolve) {PetscLogEventEnd(mglevels[l-1]->eventsmoothsolve,0,0,0,0);}
106:   return(0);
107: }