1 #include <../src/ksp/ksp/impls/rich/richardsonimpl.h> /*I "petscksp.h" I*/
2
3 /*@
4 KSPRichardsonSetScale - Set the damping factor; if this routine is not called, the factor defaults to 1.0.
5
6 Logically Collective
7
8 Input Parameters:
9 + ksp - the iterative context
10 - scale - the damping factor
11
12 Options Database Key:
13 . -ksp_richardson_scale <scale> - Set the scale factor
14
15 Level: intermediate
16
17 .seealso: [](ch_ksp), `KSPRICHARDSON`, `KSPRichardsonSetSelfScale()`
18 @*/
KSPRichardsonSetScale(KSP ksp,PetscReal scale)19 PetscErrorCode KSPRichardsonSetScale(KSP ksp, PetscReal scale)
20 {
21 PetscFunctionBegin;
22 PetscValidHeaderSpecific(ksp, KSP_CLASSID, 1);
23 PetscValidLogicalCollectiveReal(ksp, scale, 2);
24 PetscTryMethod(ksp, "KSPRichardsonSetScale_C", (KSP, PetscReal), (ksp, scale));
25 PetscFunctionReturn(PETSC_SUCCESS);
26 }
27
28 /*@
29 KSPRichardsonSetSelfScale - Sets Richardson to automatically determine optimal scaling at each iteration to minimize the 2-norm of the
30 preconditioned residual
31
32 Logically Collective
33
34 Input Parameters:
35 + ksp - the iterative context
36 - scale - `PETSC_TRUE` or the default of `PETSC_FALSE`
37
38 Options Database Key:
39 . -ksp_richardson_self_scale - Use self-scaling
40
41 Level: intermediate
42
43 Note:
44 Requires two extra work vectors. Uses an extra `VecAXPY()` and `VecDotNorm2()` per iteration.
45
46 Developer Note:
47 Could also minimize the 2-norm of the true residual with one less work vector
48
49 .seealso: [](ch_ksp), `KSPRICHARDSON`, `KSPRichardsonSetScale()`
50 @*/
KSPRichardsonSetSelfScale(KSP ksp,PetscBool scale)51 PetscErrorCode KSPRichardsonSetSelfScale(KSP ksp, PetscBool scale)
52 {
53 PetscFunctionBegin;
54 PetscValidHeaderSpecific(ksp, KSP_CLASSID, 1);
55 PetscValidLogicalCollectiveBool(ksp, scale, 2);
56 PetscTryMethod(ksp, "KSPRichardsonSetSelfScale_C", (KSP, PetscBool), (ksp, scale));
57 PetscFunctionReturn(PETSC_SUCCESS);
58 }
59