xref: /petsc/src/ksp/pc/impls/mg/fmg.c (revision 9566063d113dddea24716c546802770db7481bc0)

/*
     Full multigrid using either additive or multiplicative V or W cycle
*/
#include <petsc/private/pcmgimpl.h>

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

  PetscFunctionBegin;
  if (!transpose) {
    /* restrict the RHS through all levels to coarsest. */
    for (i=l-1; i>0; i--) {
      if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels[i]->eventinterprestrict,0,0,0,0));
      if (matapp) PetscCall(MatMatRestrict(mglevels[i]->restrct,mglevels[i]->B,&mglevels[i-1]->B));
      else PetscCall(MatRestrict(mglevels[i]->restrct,mglevels[i]->b,mglevels[i-1]->b));
      if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels[i]->eventinterprestrict,0,0,0,0));
    }

    /* work our way up through the levels */
    if (matapp) {
      if (!mglevels[0]->X) {
        PetscCall(MatDuplicate(mglevels[0]->B,MAT_DO_NOT_COPY_VALUES,&mglevels[0]->X));
      } else {
        PetscCall(MatZeroEntries(mglevels[0]->X));
      }
    } else {
      PetscCall(VecZeroEntries(mglevels[0]->x));
    }
    for (i=0; i<l-1; i++) {
      PetscCall(PCMGMCycle_Private(pc,&mglevels[i],transpose,matapp,NULL));
      if (mglevels[i+1]->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels[i+1]->eventinterprestrict,0,0,0,0));
      if (matapp) PetscCall(MatMatInterpolate(mglevels[i+1]->interpolate,mglevels[i]->X,&mglevels[i+1]->X));
      else PetscCall(MatInterpolate(mglevels[i+1]->interpolate,mglevels[i]->x,mglevels[i+1]->x));
      if (mglevels[i+1]->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels[i+1]->eventinterprestrict,0,0,0,0));
    }
    PetscCall(PCMGMCycle_Private(pc,&mglevels[l-1],transpose,matapp,NULL));
  } else {
    PetscCall(PCMGMCycle_Private(pc,&mglevels[l-1],transpose,matapp,NULL));
    for (i=l-2; i>=0; i--) {
      if (mglevels[i+1]->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels[i+1]->eventinterprestrict,0,0,0,0));
      if (matapp) PetscCall(MatMatRestrict(mglevels[i+1]->interpolate,mglevels[i+1]->X,&mglevels[i]->X));
      else PetscCall(MatRestrict(mglevels[i+1]->interpolate,mglevels[i+1]->x,mglevels[i]->x));
      if (mglevels[i+1]->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels[i+1]->eventinterprestrict,0,0,0,0));
      PetscCall(PCMGMCycle_Private(pc,&mglevels[i],transpose,matapp,NULL));
    }
    for (i=1; i<l; i++) {
      if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels[i]->eventinterprestrict,0,0,0,0));
      if (matapp) PetscCall(MatMatInterpolate(mglevels[i]->restrct,mglevels[i-1]->B,&mglevels[i]->B));
      else PetscCall(MatInterpolate(mglevels[i]->restrct,mglevels[i-1]->b,mglevels[i]->b));
      if (mglevels[i]->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels[i]->eventinterprestrict,0,0,0,0));
    }
  }
  PetscFunctionReturn(0);
}

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

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

  /* work our way up through the levels */
  if (matapp) {
    if (!mglevels[0]->X) {
      PetscCall(MatDuplicate(mglevels[0]->B,MAT_DO_NOT_COPY_VALUES,&mglevels[0]->X));
    } else {
      PetscCall(MatZeroEntries(mglevels[0]->X));
    }
  } else {
    PetscCall(VecZeroEntries(mglevels[0]->x));
  }
  for (i=0; i<l-1; i++) {
    if (mglevels[i]->eventsmoothsolve) PetscCall(PetscLogEventBegin(mglevels[i]->eventsmoothsolve,0,0,0,0));
    if (matapp) {
      PetscCall(KSPMatSolve(mglevels[i]->smoothd,mglevels[i]->B,mglevels[i]->X));
      PetscCall(KSPCheckSolve(mglevels[i]->smoothd,pc,NULL));
    } else {
      PetscCall(KSPSolve(mglevels[i]->smoothd,mglevels[i]->b,mglevels[i]->x));
      PetscCall(KSPCheckSolve(mglevels[i]->smoothd,pc,mglevels[i]->x));
    }
    if (mglevels[i]->eventsmoothsolve) PetscCall(PetscLogEventEnd(mglevels[i]->eventsmoothsolve,0,0,0,0));
    if (mglevels[i+1]->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels[i+1]->eventinterprestrict,0,0,0,0));
    if (matapp) PetscCall(MatMatInterpolate(mglevels[i+1]->interpolate,mglevels[i]->X,&mglevels[i+1]->X));
    else PetscCall(MatInterpolate(mglevels[i+1]->interpolate,mglevels[i]->x,mglevels[i+1]->x));
    if (mglevels[i+1]->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels[i+1]->eventinterprestrict,0,0,0,0));
  }
  if (mglevels[l-1]->eventsmoothsolve) PetscCall(PetscLogEventBegin(mglevels[l-1]->eventsmoothsolve,0,0,0,0));
  if (matapp) {
    PetscCall(KSPMatSolve(mglevels[l-1]->smoothd,mglevels[l-1]->B,mglevels[l-1]->X));
    PetscCall(KSPCheckSolve(mglevels[l-1]->smoothd,pc,NULL));
  } else {
    PetscCall(KSPSolve(mglevels[l-1]->smoothd,mglevels[l-1]->b,mglevels[l-1]->x));
    PetscCall(KSPCheckSolve(mglevels[l-1]->smoothd,pc,mglevels[l-1]->x));
  }
  if (mglevels[l-1]->eventsmoothsolve) PetscCall(PetscLogEventEnd(mglevels[l-1]->eventsmoothsolve,0,0,0,0));
  PetscFunctionReturn(0);
}