Actual source code: linesearchshell.c
petsc-3.6.1 2015-08-06
1: #include <petsc/private/linesearchimpl.h>
2: #include <petsc/private/snesimpl.h>
5: typedef struct {
6: SNESLineSearchUserFunc func;
7: void *ctx;
8: } SNESLineSearch_Shell;
12: /*@C
13: SNESLineSearchShellSetUserFunc - Sets the user function for the SNESLineSearch Shell implementation.
15: Not Collective
17: Input Parameters:
18: + linesearch - SNESLineSearch context
19: . func - function implementing the linesearch shell.
20: - ctx - context for func
22: Calling sequence of func:
23: + linesearch - the linesearch instance
24: - ctx - the above mentioned context
26: Usage:
28: $ PetscErrorCode shellfunc(SNESLineSearch linesearch,void * ctx)
29: $ {
30: $ Vec X,Y,F,W,G;
31: $ SNES snes;
33: $ SNESLineSearchGetSNES(linesearch,&snes);
34: $ SNESLineSearchSetReason(linesearch,SNES_LINESEARCH_SUCCEEDED);
35: $ SNESLineSearchGetVecs(linesearch,&X,&F,&Y,&W,&G);
36: $ .. determine lambda using W and G as work vecs..
37: $ VecAXPY(X,-lambda,Y);
38: $ SNESComputeFunction(snes,X,F);
39: $ SNESLineSearchComputeNorms(linesearch);
40: $ return(0);
41: $ }
42: $
43: $ ...
44: $
45: $ SNESGetLineSearch(snes, &linesearch);
46: $ SNESLineSearchSetType(linesearch, SNESLINESEARCHSHELL);
47: $ SNESLineSearchShellSetUserFunc(linesearch, shellfunc, NULL);
49: Level: advanced
51: .keywords: SNESLineSearch, Shell, user, function, set
53: .seealso: SNESLineSearchShellGetUserFunc(), SNESLINESEARCHSHELL
54: @*/
55: PetscErrorCode SNESLineSearchShellSetUserFunc(SNESLineSearch linesearch, SNESLineSearchUserFunc func, void *ctx)
56: {
57: PetscErrorCode ierr;
58: PetscBool flg;
59: SNESLineSearch_Shell *shell = (SNESLineSearch_Shell*)linesearch->data;
63: PetscObjectTypeCompare((PetscObject)linesearch,SNESLINESEARCHSHELL,&flg);
64: if (flg) {
65: shell->ctx = ctx;
66: shell->func = func;
67: }
68: return(0);
69: }
74: /*@C
75: SNESLineSearchShellGetUserFunc - Gets the user function and context for the shell implementation.
77: Not Collective
79: Level: advanced
81: .keywords: SNESLineSearch, get, Shell, user, function
83: .seealso: SNESLineSearchShellSetUserFunc()
84: @*/
85: PetscErrorCode SNESLineSearchShellGetUserFunc(SNESLineSearch linesearch, SNESLineSearchUserFunc *func, void **ctx)
86: {
87: PetscErrorCode ierr;
88: PetscBool flg;
89: SNESLineSearch_Shell *shell = (SNESLineSearch_Shell*)linesearch->data;
95: PetscObjectTypeCompare((PetscObject)linesearch,SNESLINESEARCHSHELL,&flg);
96: if (flg) {
97: *ctx = shell->ctx;
98: *func = shell->func;
99: }
100: return(0);
101: }
106: static PetscErrorCode SNESLineSearchApply_Shell(SNESLineSearch linesearch)
107: {
108: SNESLineSearch_Shell *shell = (SNESLineSearch_Shell*)linesearch->data;
109: PetscErrorCode ierr;
112: /* apply the user function */
113: if (shell->func) {
114: (*shell->func)(linesearch, shell->ctx);
115: } else SETERRQ(PetscObjectComm((PetscObject)linesearch), PETSC_ERR_USER, "SNESLineSearchShell needs to have a shell function set with SNESLineSearchShellSetUserFunc");
116: return(0);
117: }
121: static PetscErrorCode SNESLineSearchDestroy_Shell(SNESLineSearch linesearch)
122: {
123: SNESLineSearch_Shell *shell = (SNESLineSearch_Shell*)linesearch->data;
124: PetscErrorCode ierr;
127: PetscFree(shell);
128: return(0);
129: }
133: /*MC
135: SNESLINESEARCHSHELL - Provides context for a user-provided line search routine.
137: The user routine has one argument, the SNESLineSearch context. The user uses the interface to
138: extract line search parameters and set them accordingly when the computation is finished.
140: Any of the other line searches may serve as a guide to how this is to be done. There is also a basic
141: template in the documentation for SNESLineSearchShellSetUserFunc().
143: Level: advanced
145: M*/
146: PETSC_EXTERN PetscErrorCode SNESLineSearchCreate_Shell(SNESLineSearch linesearch)
147: {
149: SNESLineSearch_Shell *shell;
150: PetscErrorCode ierr;
153: linesearch->ops->apply = SNESLineSearchApply_Shell;
154: linesearch->ops->destroy = SNESLineSearchDestroy_Shell;
155: linesearch->ops->setfromoptions = NULL;
156: linesearch->ops->reset = NULL;
157: linesearch->ops->view = NULL;
158: linesearch->ops->setup = NULL;
160: PetscNewLog(linesearch,&shell);
162: linesearch->data = (void*) shell;
163: return(0);
164: }