2: #include <petsc/private/pcimpl.h>

  4: static PetscErrorCode PCApply_Mat(PC pc,Vec x,Vec y)
  5: {

  9:   MatMult(pc->pmat,x,y);
 10:   return(0);
 11: }

 13: static PetscErrorCode PCMatApply_Mat(PC pc,Mat X,Mat Y)
 14: {

 18:   MatMatMult(pc->pmat,X,MAT_REUSE_MATRIX,PETSC_DEFAULT,&Y);
 19:   return(0);
 20: }

 22: static PetscErrorCode PCApplyTranspose_Mat(PC pc,Vec x,Vec y)
 23: {

 27:   MatMultTranspose(pc->pmat,x,y);
 28:   return(0);
 29: }

 31: static PetscErrorCode PCDestroy_Mat(PC pc)
 32: {
 34:   return(0);
 35: }

 37: /*MC
 38:      PCMAT - A preconditioner obtained by multiplying by the preconditioner matrix supplied
 39:              in PCSetOperators() or KSPSetOperators()

 41:    Notes:
 42:     This one is a little strange. One rarely has an explicit matrix that approximates the
 43:          inverse of the matrix they wish to solve for.

 45:    Level: intermediate

 47: .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC,
 48:            PCSHELL

 50: M*/

 52: PETSC_EXTERN PetscErrorCode PCCreate_Mat(PC pc)
 53: {
 55:   pc->ops->apply               = PCApply_Mat;
 56:   pc->ops->matapply            = PCMatApply_Mat;
 57:   pc->ops->applytranspose      = PCApplyTranspose_Mat;
 58:   pc->ops->setup               = NULL;
 59:   pc->ops->destroy             = PCDestroy_Mat;
 60:   pc->ops->setfromoptions      = NULL;
 61:   pc->ops->view                = NULL;
 62:   pc->ops->applyrichardson     = NULL;
 63:   pc->ops->applysymmetricleft  = NULL;
 64:   pc->ops->applysymmetricright = NULL;
 65:   return(0);
 66: }