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  ierr = PetscObjectStateIncrease((PetscObject)ps);CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "PSTranslateRKS"

/*@C

   PSTranslateRKS - Computes a modification of the projected matrix corresponding

   to an update of the shift in a rational Krylov method.

   Logically Collective on PS

   Input Parameters:

+  ps    - the projected system context

-  alpha - the translation amount

   Notes:

   This function is intended for use in the context of Krylov methods only.

   It takes the leading (k+1,k) submatrix of A, containing the truncated

   Rayleigh quotient of a Krylov-Schur relation computed from a shift

   sigma1 and transforms it to obtain a Krylov relation as if computed

   from a different shift sigma2. The new matrix is computed as

   1.0/alpha*(eye(k)-Q*inv(R)), where [Q,R]=qr(eye(k)-alpha*A) and

   alpha = sigma1-sigma2.

   Matrix Q is placed in PS_MAT_Q so that it can be used to update the

   Krylov basis.

   Level: developer

@*/

PetscErrorCode PSTranslateRKS(PS ps,PetscScalar alpha)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(ps,PS_CLASSID,1);

  if (!ps->ops->transrks) SETERRQ1(((PetscObject)ps)->comm,PETSC_ERR_SUP,"PS type %s",((PetscObject)ps)->type_name);

  ierr = PetscLogEventBegin(PS_Other,ps,0,0,0);CHKERRQ(ierr);

  ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);

  ierr = (*ps->ops->transrks)(ps,alpha);CHKERRQ(ierr);

  ierr = PetscFPTrapPop();CHKERRQ(ierr);

  ierr = PetscLogEventEnd(PS_Other,ps,0,0,0);CHKERRQ(ierr);

  ps->state   = PS_STATE_RAW;

  ps->compact = PETSC_FALSE;