Date: 2022-03-31T04:47:57+00:00

Actual source code: fmg.c

      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: {
      8:   PetscInt       i,l = mglevels[0]->levels;

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

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

     56: PetscErrorCode PCMGKCycle_Private(PC pc,PC_MG_Levels **mglevels,PetscBool transpose,PetscBool matapp)
     57: {
     58:   PetscInt       i,l = mglevels[0]->levels;

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

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