Actual source code: preonly.c
1: #define PETSCKSP_DLL
3: #include include/private/kspimpl.h
7: static PetscErrorCode KSPSetUp_PREONLY(KSP ksp)
8: {
10: return(0);
11: }
15: static PetscErrorCode KSPSolve_PREONLY(KSP ksp)
16: {
18: PetscTruth diagonalscale;
21: PCDiagonalScale(ksp->pc,&diagonalscale);
22: if (diagonalscale) SETERRQ1(PETSC_ERR_SUP,"Krylov method %s does not support diagonal scaling",ksp->type_name);
23: if (!ksp->guess_zero) {
24: SETERRQ(PETSC_ERR_USER,"Running KSP of preonly doesn't make sense with nonzero initial guess\n\
25: you probably want a KSP type of Richardson");
26: }
27: ksp->its = 0;
28: KSP_PCApply(ksp,ksp->vec_rhs,ksp->vec_sol);
29: ksp->its = 1;
30: ksp->reason = KSP_CONVERGED_ITS;
31: return(0);
32: }
34: /*MC
35: KSPPREONLY - This implements a stub method that applies ONLY the preconditioner.
36: This may be used in inner iterations, where it is desired to
37: allow multiple iterations as well as the "0-iteration" case. It is
38: commonly used with the direct solver preconditioners like PCLU and PCCHOLESKY
40: Options Database Keys:
41: . see KSPSolve()
43: Level: beginner
45: .seealso: KSPCreate(), KSPSetType(), KSPType (for list of available types), KSP
47: M*/
52: PetscErrorCode KSPCreate_PREONLY(KSP ksp)
53: {
55: ksp->data = (void*)0;
56: ksp->ops->setup = KSPSetUp_PREONLY;
57: ksp->ops->solve = KSPSolve_PREONLY;
58: ksp->ops->destroy = KSPDefaultDestroy;
59: ksp->ops->buildsolution = KSPDefaultBuildSolution;
60: ksp->ops->buildresidual = KSPDefaultBuildResidual;
61: ksp->ops->setfromoptions = 0;
62: ksp->ops->view = 0;
63: return(0);
64: }