1 #include <petsc/private/taolinesearchimpl.h>
2
TaoLineSearchView_Unit(TaoLineSearch ls,PetscViewer viewer)3 static PetscErrorCode TaoLineSearchView_Unit(TaoLineSearch ls, PetscViewer viewer)
4 {
5 PetscBool isascii;
6
7 PetscFunctionBegin;
8 PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
9 if (isascii) PetscCall(PetscViewerASCIIPrintf(viewer, " Line Search: Unit Step %g.\n", (double)ls->initstep));
10 PetscFunctionReturn(PETSC_SUCCESS);
11 }
12
13 /* Take unit step (newx = startx + initstep*step_direction) */
TaoLineSearchApply_Unit(TaoLineSearch ls,Vec x,PetscReal * f,Vec g,Vec step_direction)14 static PetscErrorCode TaoLineSearchApply_Unit(TaoLineSearch ls, Vec x, PetscReal *f, Vec g, Vec step_direction)
15 {
16 PetscFunctionBegin;
17 PetscCall(TaoLineSearchMonitor(ls, 0, *f, 0.0));
18 ls->step = ls->initstep;
19 PetscCall(VecAXPY(x, ls->step, step_direction));
20 PetscCall(TaoLineSearchComputeObjectiveAndGradient(ls, x, f, g));
21 PetscCall(TaoLineSearchMonitor(ls, 1, *f, ls->step));
22 ls->reason = TAOLINESEARCH_SUCCESS;
23 PetscFunctionReturn(PETSC_SUCCESS);
24 }
25
26 /*MC
27 TAOLINESEARCHUNIT - Line-search type that disables line search and accepts the unit step length every time
28
29 Options Database Keys:
30 . -tao_ls_stepinit <step> - steplength
31
32 Level: developer
33
34 .seealso: `Tao`, `TaoLineSearch`, `TaoLineSearchCreate()`, `TaoLineSearchSetType()`, `TaoLineSearchApply()`
35 M*/
TaoLineSearchCreate_Unit(TaoLineSearch ls)36 PETSC_EXTERN PetscErrorCode TaoLineSearchCreate_Unit(TaoLineSearch ls)
37 {
38 PetscFunctionBegin;
39 ls->ops->setup = NULL;
40 ls->ops->reset = NULL;
41 ls->ops->monitor = NULL;
42 ls->ops->apply = TaoLineSearchApply_Unit;
43 ls->ops->view = TaoLineSearchView_Unit;
44 PetscFunctionReturn(PETSC_SUCCESS);
45 }
46