xref: /petsc/src/mat/impls/shell/shell.c (revision a62d957ae685a2070aaf3345f4f6f1b8f7cef2e2)
1 #ifndef lint
2 static char vcid[] = "$Id: shell.c,v 1.28 1996/03/28 22:00:13 curfman Exp curfman $";
3 #endif
4 
5 /*
6    This provides a simple shell for Fortran (and C programmers) to
7   create a very simple matrix class for use with KSP without coding
8   much of anything.
9 */
10 
11 #include "petsc.h"
12 #include "matimpl.h"        /*I "mat.h" I*/
13 #include "vec/vecimpl.h"
14 
15 typedef struct {
16   int  m, n;                       /* rows, columns */
17   int  (*destroy)(void*);
18   void *ctx;
19 } Mat_Shell;
20 
21 /*@
22     MatShellGetContext - Returns the user-provided context associated with a shell matrix.
23 
24     Input Parameter:
25 .   mat - the matrix, should have been created with MatCreateShell()
26 
27     Output Parameter:
28 .   ctx - the user provided context
29 
30     Notes:
31     This routine is intended for use within various shell matrix routines,
32     as set with MatShellSetOperation().
33 
34 .keywords: matrix, shell, get, context
35 
36 .seealso: MatCreateShell(), MatShellSetOperation()
37 @*/
38 int MatShellGetContext(Mat mat,void **ctx)
39 {
40   PetscValidHeaderSpecific(mat,MAT_COOKIE);
41   if (mat->type != MATSHELL) *ctx = 0;
42   else                       *ctx = ((Mat_Shell *) (mat->data))->ctx;
43   return 0;
44 }
45 
46 static int MatGetSize_Shell(Mat mat,int *m,int *n)
47 {
48   Mat_Shell *shell = (Mat_Shell *) mat->data;
49   *m = shell->m; *n = shell->n;
50   return 0;
51 }
52 
53 static int MatDestroy_Shell(PetscObject obj)
54 {
55   int       ierr;
56   Mat       mat = (Mat) obj;
57   Mat_Shell *shell;
58 
59   shell = (Mat_Shell *) mat->data;
60   if (shell->destroy) {ierr = (*shell->destroy)(obj);CHKERRQ(ierr);}
61   PetscFree(shell);
62   return 0;
63 }
64 
65 static struct _MatOps MatOps = {0,0,
66        0,
67        0,0,0,0,
68        0,0,0,0,
69        0,0,
70        0,
71        0,
72        0,0,0,
73        0,
74        0,0,0,
75        0,0,
76        0,
77        0,0,0,0,
78        0,0,MatGetSize_Shell,
79        0,0,0,0,
80        0,0,0,0 };
81 
82 /*@C
83    MatCreateShell - Creates a new matrix class for use with a user-defined
84    private data storage format.
85 
86    Input Parameters:
87 .  comm - MPI communicator
88 .  m - number of rows
89 .  n - number of columns
90 .  ctx - pointer to data needed by the matrix routines
91 
92    Output Parameter:
93 .  mat - the matrix
94 
95    Notes:
96    The shell matrix type is intended to provide a simple class to use
97    with KSP (such as, for use with matrix-free methods). You should not
98    use the shell type if you plan to define a complete matrix class.
99 
100    Usage:
101 $   MatCreateShell(m,n,ctx,&mat);
102 $   MatShellSetOperation(mat,MAT_MULT,mult);
103 $   [ Use matrix for operations that have been set ]
104 $   MatDestroy(mat);
105 
106 .keywords: matrix, shell, create
107 
108 .seealso: MatSetOperation(), MatHasOperation(), MatShellGetContext()
109 @*/
110 int MatCreateShell(MPI_Comm comm,int m,int n,void *ctx,Mat *mat)
111 {
112   Mat       newmat;
113   Mat_Shell *shell;
114 
115   PetscHeaderCreate(newmat,_Mat,MAT_COOKIE,MATSHELL,comm);
116   PLogObjectCreate(newmat);
117   *mat              = newmat;
118   newmat->factor    = 0;
119   newmat->destroy   = MatDestroy_Shell;
120   newmat->assembled = PETSC_TRUE;
121   PetscMemcpy(&newmat->ops,&MatOps,sizeof(struct _MatOps));
122 
123   shell          = PetscNew(Mat_Shell); CHKPTRQ(shell);
124   PetscMemzero(shell,sizeof(Mat_Shell));
125   newmat->data   = (void *) shell;
126   shell->m       = m;
127   shell->n       = n;
128   shell->ctx     = ctx;
129   return 0;
130 }
131 
132 /*@
133     MatShellSetOperation - Allows user to set a matrix operation for a shell matrix.
134 
135     Input Parameters:
136 .   mat - the shell matrix
137 .   op - the name of the operation
138 .   f - the function that provides the operation.
139 
140     Usage:
141 $      extern int usermult(Mat,Vec,Vec);
142 $      ierr = MatCreateShell(comm,m,m,ctx,&A);
143 $      ierr = MatShellSetOperation(A,MAT_MULT,usermult);
144 
145     Notes:
146     See the file petsc/include/mat.h for a complete list of matrix
147     operations, which all have the form MAT_<OPERATION>, where
148     <OPERATION> is the name (in all capital letters) of the
149     user interface routine (e.g., MatMult() -> MAT_MULT).
150 
151     All user-provided functions should have the same calling
152     sequence as the usual matrix interface routines, e.g.,
153 $       MatMult(Mat,Vec,Vec) -> usermult(Mat,Vec,Vec)
154     since they are intended to be accessed via the usual
155     matrix interface routines.
156 
157     Within each user-defined routine, the user should call
158     MatShellGetContext() to obtain the user-defined context that was
159     set by MatCreateShell().
160 
161 .keywords: matrix, shell, set, operation
162 
163 .seealso: MatCreateShell(), MatShellGetContext()
164 @*/
165 int MatShellSetOperation(Mat mat,MatOperation op, void *f)
166 {
167   PetscValidHeaderSpecific(mat,MAT_COOKIE);
168 
169   if (op == MAT_DESTROY) {
170     if (mat->type == MATSHELL) {
171        Mat_Shell *shell = (Mat_Shell *) mat->data;
172        shell->destroy                                 = (int (*)(void*)) f;
173     }
174     else mat->destroy                                 = (int (*)(PetscObject)) f;
175   }
176   else if (op == MAT_VIEW) mat->view                  = (int (*)(PetscObject,Viewer)) f;
177   else                     (((void **)&mat->ops)[op]) = f;
178 
179   return 0;
180 }
181 
182