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: }