1: #define PETSCKSP_DLL

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

 10: PetscErrorCode PCApply_None(PC pc,Vec x,Vec y)
 11: {

 15:   VecCopy(x,y);
 16:   return(0);
 17: }

 19: /*MC
 20:      PCNONE - This is used when you wish to employ a nonpreconditioned
 21:              Krylov method. 

 23:    Level: beginner

 25:   Concepts: preconditioners

 27:   Notes: This is implemented by a VecCopy()

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

 35: PetscErrorCode  PCCreate_None(PC pc)
 36: {
 38:   pc->ops->apply               = PCApply_None;
 39:   pc->ops->applytranspose      = PCApply_None;
 40:   pc->ops->destroy             = 0;
 41:   pc->ops->setup               = 0;
 42:   pc->ops->view                = 0;
 43:   pc->ops->applysymmetricleft  = PCApply_None;
 44:   pc->ops->applysymmetricright = PCApply_None;

 46:   pc->data                     = 0;
 47:   return(0);
 48: }