Actual source code: richscale.c
2: #include <../src/ksp/ksp/impls/rich/richardsonimpl.h>
4: /*@
5: KSPRichardsonSetScale - Set the damping factor; if this routine is not called, the factor
6: defaults to 1.0.
8: Logically Collective on ksp
10: Input Parameters:
11: + ksp - the iterative context
12: - scale - the relaxation factor
14: Options Database Keys:
15: . -ksp_richardson_self <scale> - Set the scale factor
17: Level: intermediate
19: .seealso: KSPRICHARDSON, KSPRichardsonSetSelfScale()
20: @*/
21: PetscErrorCode KSPRichardsonSetScale(KSP ksp,PetscReal scale)
22: {
25: PetscTryMethod(ksp,"KSPRichardsonSetScale_C",(KSP,PetscReal),(ksp,scale));
26: return 0;
27: }
29: /*@
30: KSPRichardsonSetSelfScale - Sets Richardson to automatically determine optimal scaling at each iteration to minimize the 2-norm of the
31: preconditioned residual
33: Logically Collective on ksp
35: Input Parameters:
36: + ksp - the iterative context
37: - scale - PETSC_TRUE or the default of PETSC_FALSE
39: Options Database Keys:
40: . -ksp_richardson_self_scale - Use self-scaling
42: Level: intermediate
44: Notes:
45: Requires two extra work vectors. Uses an extra VecAXPY() and VecDotNorm2() per iteration.
47: Developer Notes:
48: Could also minimize the 2-norm of the true residual with one less work vector
50: .seealso: KSPRICHARDSON, KSPRichardsonSetScale()
51: @*/
52: PetscErrorCode KSPRichardsonSetSelfScale(KSP ksp,PetscBool scale)
53: {
56: PetscTryMethod(ksp,"KSPRichardsonSetSelfScale_C",(KSP,PetscBool),(ksp,scale));
57: return 0;
58: }