xref: /petsc/src/snes/mf/snesmfj.c (revision 174415d91b2a567e2f20ff6ea384fdd4e208fd3e)
1 #define PETSCSNES_DLL
2 
3 #include "include/private/snesimpl.h"  /*I  "petscsnes.h" I*/
4 #include "include/private/matimpl.h"
5 #include "src/mat/impls/mffd/mffdimpl.h"
6 
7 #undef __FUNCT__
8 #define __FUNCT__ "MatMFFDComputeJacobian"
9 /*@
10    MatMFFDComputeJacobian - Tells the matrix-free Jacobian object the new location at which
11        Jacobian matrix vector products will be computed at, i.e. J(x) * a. The x is obtained
12        from the SNES object (using SNESGetSolution()).
13 
14    Collective on SNES
15 
16    Input Parameters:
17 +   snes - the nonlinear solver context
18 .   x - the point at which the Jacobian vector products will be performed
19 .   jac - the matrix-free Jacobian object
20 .   B - either the same as jac or another matrix type (ignored)
21 .   flag - not relevent for matrix-free form
22 -   dummy - the user context (ignored)
23 
24    Level: developer
25 
26    Warning:
27       If MatMFFDSetBase() is ever called on jac then this routine will NO longer get
28     the x from the SNES object and MatMFFDSetBase() must from that point on be used to
29     change the base vector x.
30 
31    Notes:
32      This can be passed into SNESSetJacobian() when using a completely matrix-free solver,
33      that is the B matrix is also the same matrix operator. This is used when you select
34      -snes_mf but rarely used directly by users.
35 
36 .seealso: MatMFFDGetH(), MatCreateSNESMF(), MatCreateMFFD(), MATMFFD,
37           MatMFFDSetHHistory(),
38           MatMFFDKSPMonitor(), MatMFFDSetFunctionError(), MatMFFDCreate(), SNESSetJacobian()
39 
40 @*/
41 PetscErrorCode PETSCSNES_DLLEXPORT MatMFFDComputeJacobian(SNES snes,Vec x,Mat *jac,Mat *B,MatStructure *flag,void *dummy)
42 {
43   PetscErrorCode ierr;
44   PetscFunctionBegin;
45   ierr = MatAssemblyBegin(*jac,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
46   ierr = MatAssemblyEnd(*jac,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
47   PetscFunctionReturn(0);
48 }
49 
50 PetscErrorCode MatAssemblyEnd_MFFD(Mat,MatAssemblyType);
51 #undef __FUNCT__
52 #define __FUNCT__ "MatAssemblyEnd_SNESMF"
53 /*
54    MatAssemblyEnd_SNESMF - Calls MatAssemblyEnd_MFFD() and then sets the
55     base from the SNES context
56 
57 */
58 PetscErrorCode MatAssemblyEnd_SNESMF(Mat J,MatAssemblyType mt)
59 {
60   PetscErrorCode ierr;
61   MatMFFD        j = (MatMFFD)J->data;
62   SNES           snes = (SNES)j->funcctx;
63 
64   PetscFunctionBegin;
65   ierr = MatAssemblyEnd_MFFD(J,mt);CHKERRQ(ierr);
66 
67   ierr = SNESGetSolution(snes,&j->current_u);CHKERRQ(ierr);
68   ierr = SNESGetFunction(snes,&j->current_f,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);
69   if (!j->w) {
70     ierr = VecDuplicate(j->current_u, &j->w);CHKERRQ(ierr);
71   }
72   printf("snesmf assembly end");
73   VecView(j->current_u,0);
74   PetscFunctionReturn(0);
75 }
76 
77 EXTERN_C_BEGIN
78 extern PetscErrorCode PETSCMAT_DLLEXPORT MatMFFDSetBase_FD(Mat,Vec,Vec);
79 /*
80     This routine resets the MatAssemblyEnd() for the MatMFFD created from MatCreateSNESMF() so that it NO longer
81   uses the solution in the SNES object to update the base. See the warning in MatCreateSNESMF().
82 */
83 #undef __FUNCT__
84 #define __FUNCT__ "MatMFFDSetBase_SNESMF"
85 PetscErrorCode PETSCMAT_DLLEXPORT MatMFFDSetBase_SNESMF(Mat J,Vec U,Vec F)
86 {
87   PetscErrorCode ierr;
88 
89   PetscFunctionBegin;
90   ierr = MatMFFDSetBase_FD(J,U,F);CHKERRQ(ierr);
91   J->ops->assemblyend = MatAssemblyEnd_MFFD;
92   PetscFunctionReturn(0);
93 }
94 EXTERN_C_END
95 
96 #undef __FUNCT__
97 #define __FUNCT__ "MatCreateSNESMF"
98 /*@
99    MatCreateSNESMF - Creates a matrix-free matrix context for use with
100    a SNES solver.  This matrix can be used as the Jacobian argument for
101    the routine SNESSetJacobian(). See MatCreateMFFD() for details on how
102    the finite difference computation is done.
103 
104    Collective on SNES and Vec
105 
106    Input Parameters:
107 +  snes - the SNES context
108 -  x - vector where SNES solution is to be stored.
109 
110    Output Parameter:
111 .  J - the matrix-free matrix
112 
113    Level: advanced
114 
115    Warning:
116       If MatMFFDSetBase() is ever called on jac then this routine will NO longer get
117     the x from the SNES object and MatMFFDSetBase() must from that point on be used to
118     change the base vector x.
119 
120    Notes: The difference between this routine and MatCreateMFFD() is that this matrix
121      automatically gets the current base vector from the SNES object and not from an
122      explicit call to MatMFFDSetBase().
123 
124 .seealso: MatDestroy(), MatMFFDSetFunctionError(), MatMFFDDefaultSetUmin()
125           MatMFFDSetHHistory(), MatMFFDResetHHistory(), MatCreateMFFD(),
126           MatMFFDGetH(),MatMFFDKSPMonitor(), MatMFFDRegisterDynamic), MatMFFDComputeJacobian()
127 
128 @*/
129 PetscErrorCode PETSCSNES_DLLEXPORT MatCreateSNESMF(SNES snes,Vec x,Mat *J)
130 {
131   PetscErrorCode ierr;
132 
133   PetscFunctionBegin;
134   ierr = MatCreateMFFD(x,J);CHKERRQ(ierr);
135   ierr = MatMFFDSetFunction(*J,(PetscErrorCode (*)(void*, _p_Vec*, _p_Vec*))SNESComputeFunction,snes);CHKERRQ(ierr);
136   (*J)->ops->assemblyend = MatAssemblyEnd_SNESMF;
137   ierr = PetscObjectComposeFunctionDynamic((PetscObject)*J,"MatMFFDSetBase_C","MatMFFDSetBase_SNESMF",MatMFFDSetBase_SNESMF);CHKERRQ(ierr);
138   PetscFunctionReturn(0);
139 }
140 
141 
142 
143 
144 
145 
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