2: /*
  3:     Identity preconditioner, simply copies vector x to y.
  4: */
  5: #include <petsc/private/pcimpl.h>

  7: PetscErrorCode PCApply_None(PC pc,Vec x,Vec y)
  8: {

 12:   VecCopy(x,y);
 13:   return(0);
 14: }

 16: PetscErrorCode PCMatApply_None(PC pc,Mat X,Mat Y)
 17: {

 21:   MatCopy(X,Y,SAME_NONZERO_PATTERN);
 22:   return(0);
 23: }

 25: /*MC
 26:      PCNONE - This is used when you wish to employ a nonpreconditioned
 27:              Krylov method.

 29:    Level: beginner

 31:   Notes:
 32:     This is implemented by a VecCopy()

 34: .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC
 35: M*/

 37: PETSC_EXTERN PetscErrorCode PCCreate_None(PC pc)
 38: {
 40:   pc->ops->apply               = PCApply_None;
 41:   pc->ops->matapply            = PCMatApply_None;
 42:   pc->ops->applytranspose      = PCApply_None;
 43:   pc->ops->destroy             = NULL;
 44:   pc->ops->setup               = NULL;
 45:   pc->ops->view                = NULL;
 46:   pc->ops->applysymmetricleft  = PCApply_None;
 47:   pc->ops->applysymmetricright = PCApply_None;

 49:   pc->data = NULL;
 50:   return(0);
 51: }