Actual source code: richscale.c
petsc-3.10.3 2018-12-18
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: .keywords: KSP, Richardson, set, scale
20: @*/
21: PetscErrorCode KSPRichardsonSetScale(KSP ksp,PetscReal scale)
22: {
28: PetscTryMethod(ksp,"KSPRichardsonSetScale_C",(KSP,PetscReal),(ksp,scale));
29: return(0);
30: }
32: /*@
33: KSPRichardsonSetSelfScale - Sets Richardson to automatically determine optimal scaling at each iteration to minimize the 2-norm of the
34: preconditioned residual
36: Logically Collective on KSP
38: Input Parameters:
39: + ksp - the iterative context
40: - scale - PETSC_TRUE or the default of PETSC_FALSE
42: Options Database Keys:
43: . -ksp_richardson_self_scale - Use self-scaling
45: Level: intermediate
47: Notes:
48: Requires two extra work vectors. Uses an extra VecAXPY() and VecDotNorm2() per iteration.
50: Developer Notes:
51: Could also minimize the 2-norm of the true residual with one less work vector
54: .keywords: KSP, Richardson, set, scale
55: @*/
56: PetscErrorCode KSPRichardsonSetSelfScale(KSP ksp,PetscBool scale)
57: {
63: PetscTryMethod(ksp,"KSPRichardsonSetSelfScale_C",(KSP,PetscBool),(ksp,scale));
64: return(0);
65: }