xref: /petsc/src/mat/tutorials/ex8.c (revision c4762a1b19cd2af06abeed90e8f9d34fb975dd94)
1*c4762a1bSJed Brown 
2*c4762a1bSJed Brown static char help[] = "Shows how to add a new MatOperation to AIJ MatType\n\n";
3*c4762a1bSJed Brown 
4*c4762a1bSJed Brown #include <petscmat.h>
5*c4762a1bSJed Brown #include <petscblaslapack.h>
6*c4762a1bSJed Brown 
7*c4762a1bSJed Brown static PetscErrorCode MatScaleUserImpl_SeqAIJ(Mat inA,PetscScalar alpha)
8*c4762a1bSJed Brown {
9*c4762a1bSJed Brown   PetscErrorCode ierr;
10*c4762a1bSJed Brown 
11*c4762a1bSJed Brown   PetscFunctionBegin;
12*c4762a1bSJed Brown   ierr = MatScale(inA,alpha);CHKERRQ(ierr);
13*c4762a1bSJed Brown   PetscFunctionReturn(0);
14*c4762a1bSJed Brown }
15*c4762a1bSJed Brown 
16*c4762a1bSJed Brown extern PetscErrorCode MatScaleUserImpl(Mat,PetscScalar);
17*c4762a1bSJed Brown 
18*c4762a1bSJed Brown static PetscErrorCode MatScaleUserImpl_MPIAIJ(Mat A,PetscScalar aa)
19*c4762a1bSJed Brown {
20*c4762a1bSJed Brown   PetscErrorCode ierr;
21*c4762a1bSJed Brown   Mat            AA,AB;
22*c4762a1bSJed Brown 
23*c4762a1bSJed Brown   PetscFunctionBegin;
24*c4762a1bSJed Brown   ierr = MatMPIAIJGetSeqAIJ(A,&AA,&AB,NULL);CHKERRQ(ierr);
25*c4762a1bSJed Brown   ierr = MatScaleUserImpl(AA,aa);CHKERRQ(ierr);
26*c4762a1bSJed Brown   ierr = MatScaleUserImpl(AB,aa);CHKERRQ(ierr);
27*c4762a1bSJed Brown   PetscFunctionReturn(0);
28*c4762a1bSJed Brown }
29*c4762a1bSJed Brown 
30*c4762a1bSJed Brown /* This routine registers MatScaleUserImpl_SeqAIJ() and
31*c4762a1bSJed Brown    MatScaleUserImpl_MPIAIJ() as methods providing MatScaleUserImpl()
32*c4762a1bSJed Brown    functionality for SeqAIJ and MPIAIJ matrix-types */
33*c4762a1bSJed Brown PetscErrorCode RegisterMatScaleUserImpl(Mat mat)
34*c4762a1bSJed Brown {
35*c4762a1bSJed Brown   PetscErrorCode ierr;
36*c4762a1bSJed Brown   PetscMPIInt    size;
37*c4762a1bSJed Brown 
38*c4762a1bSJed Brown   ierr = MPI_Comm_size(PetscObjectComm((PetscObject)mat), &size);CHKERRQ(ierr);
39*c4762a1bSJed Brown 
40*c4762a1bSJed Brown   if (size == 1) { /* SeqAIJ Matrix */
41*c4762a1bSJed Brown     ierr = PetscObjectComposeFunction((PetscObject)mat,"MatScaleUserImpl_C",MatScaleUserImpl_SeqAIJ);CHKERRQ(ierr);
42*c4762a1bSJed Brown 
43*c4762a1bSJed Brown   } else { /* MPIAIJ Matrix */
44*c4762a1bSJed Brown     Mat AA,AB;
45*c4762a1bSJed Brown     ierr = MatMPIAIJGetSeqAIJ(mat,&AA,&AB,NULL);CHKERRQ(ierr);
46*c4762a1bSJed Brown     ierr = PetscObjectComposeFunction((PetscObject)mat,"MatScaleUserImpl_C",MatScaleUserImpl_MPIAIJ);CHKERRQ(ierr);
47*c4762a1bSJed Brown     ierr = PetscObjectComposeFunction((PetscObject)AA,"MatScaleUserImpl_C",MatScaleUserImpl_SeqAIJ);CHKERRQ(ierr);
48*c4762a1bSJed Brown     ierr = PetscObjectComposeFunction((PetscObject)AB,"MatScaleUserImpl_C",MatScaleUserImpl_SeqAIJ);CHKERRQ(ierr);
49*c4762a1bSJed Brown   }
50*c4762a1bSJed Brown   PetscFunctionReturn(0);
51*c4762a1bSJed Brown }
52*c4762a1bSJed Brown 
53*c4762a1bSJed Brown /* this routines queries the already registered MatScaleUserImp_XXX
54*c4762a1bSJed Brown    implementations for the given matrix, and calls the correct
55*c4762a1bSJed Brown    routine. i.e if MatType is SeqAIJ, MatScaleUserImpl_SeqAIJ() gets
56*c4762a1bSJed Brown    called, and if MatType is MPIAIJ, MatScaleUserImpl_MPIAIJ() gets
57*c4762a1bSJed Brown    called */
58*c4762a1bSJed Brown PetscErrorCode MatScaleUserImpl(Mat mat,PetscScalar a)
59*c4762a1bSJed Brown {
60*c4762a1bSJed Brown   PetscErrorCode ierr,(*f)(Mat,PetscScalar);
61*c4762a1bSJed Brown 
62*c4762a1bSJed Brown   PetscFunctionBegin;
63*c4762a1bSJed Brown   ierr = PetscObjectQueryFunction((PetscObject)mat,"MatScaleUserImpl_C",&f);CHKERRQ(ierr);
64*c4762a1bSJed Brown   if (f) {
65*c4762a1bSJed Brown     ierr = (*f)(mat,a);CHKERRQ(ierr);
66*c4762a1bSJed Brown   }
67*c4762a1bSJed Brown   PetscFunctionReturn(0);
68*c4762a1bSJed Brown }
69*c4762a1bSJed Brown 
70*c4762a1bSJed Brown /* Main user code that uses MatScaleUserImpl() */
71*c4762a1bSJed Brown 
72*c4762a1bSJed Brown int main(int argc,char **args)
73*c4762a1bSJed Brown {
74*c4762a1bSJed Brown   Mat            mat;
75*c4762a1bSJed Brown   PetscInt       i,j,m = 2,n,Ii,J;
76*c4762a1bSJed Brown   PetscErrorCode ierr;
77*c4762a1bSJed Brown   PetscScalar    v,none = -1.0;
78*c4762a1bSJed Brown   PetscMPIInt    rank,size;
79*c4762a1bSJed Brown 
80*c4762a1bSJed Brown 
81*c4762a1bSJed Brown   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
82*c4762a1bSJed Brown   ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRQ(ierr);
83*c4762a1bSJed Brown   ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRQ(ierr);
84*c4762a1bSJed Brown   n    = 2*size;
85*c4762a1bSJed Brown 
86*c4762a1bSJed Brown   /* create the matrix */
87*c4762a1bSJed Brown   ierr = MatCreate(PETSC_COMM_WORLD,&mat);CHKERRQ(ierr);
88*c4762a1bSJed Brown   ierr = MatSetSizes(mat,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n);CHKERRQ(ierr);
89*c4762a1bSJed Brown   ierr = MatSetType(mat,MATAIJ);CHKERRQ(ierr);
90*c4762a1bSJed Brown   ierr = MatSetUp(mat);CHKERRQ(ierr);
91*c4762a1bSJed Brown 
92*c4762a1bSJed Brown   /* register user defined MatScaleUser() operation for both SeqAIJ
93*c4762a1bSJed Brown      and MPIAIJ types */
94*c4762a1bSJed Brown   ierr = RegisterMatScaleUserImpl(mat);CHKERRQ(ierr);
95*c4762a1bSJed Brown 
96*c4762a1bSJed Brown   /* assemble the matrix */
97*c4762a1bSJed Brown   for (i=0; i<m; i++) {
98*c4762a1bSJed Brown     for (j=2*rank; j<2*rank+2; j++) {
99*c4762a1bSJed Brown       v = -1.0;  Ii = j + n*i;
100*c4762a1bSJed Brown       if (i>0)   {J = Ii - n; ierr = MatSetValues(mat,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
101*c4762a1bSJed Brown       if (i<m-1) {J = Ii + n; ierr = MatSetValues(mat,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
102*c4762a1bSJed Brown       if (j>0)   {J = Ii - 1; ierr = MatSetValues(mat,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
103*c4762a1bSJed Brown       if (j<n-1) {J = Ii + 1; ierr = MatSetValues(mat,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
104*c4762a1bSJed Brown       v = 4.0; ierr = MatSetValues(mat,1,&Ii,1,&Ii,&v,INSERT_VALUES);CHKERRQ(ierr);
105*c4762a1bSJed Brown     }
106*c4762a1bSJed Brown   }
107*c4762a1bSJed Brown   ierr = MatAssemblyBegin(mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
108*c4762a1bSJed Brown   ierr = MatAssemblyEnd(mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
109*c4762a1bSJed Brown 
110*c4762a1bSJed Brown   /* check the matrix before and after scaling by -1.0 */
111*c4762a1bSJed Brown   ierr = PetscPrintf(PETSC_COMM_WORLD,"Matrix _before_ MatScaleUserImpl() operation\n");CHKERRQ(ierr);
112*c4762a1bSJed Brown   ierr = MatView(mat,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
113*c4762a1bSJed Brown   ierr = MatScaleUserImpl(mat,none);CHKERRQ(ierr);
114*c4762a1bSJed Brown   ierr = PetscPrintf(PETSC_COMM_WORLD,"Matrix _after_ MatScaleUserImpl() operation\n");CHKERRQ(ierr);
115*c4762a1bSJed Brown   ierr = MatView(mat,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
116*c4762a1bSJed Brown 
117*c4762a1bSJed Brown   ierr = MatDestroy(&mat);CHKERRQ(ierr);
118*c4762a1bSJed Brown   ierr = PetscFinalize();
119*c4762a1bSJed Brown   return ierr;
120*c4762a1bSJed Brown }
121*c4762a1bSJed Brown 
122*c4762a1bSJed Brown 
123*c4762a1bSJed Brown /*TEST
124*c4762a1bSJed Brown 
125*c4762a1bSJed Brown    test:
126*c4762a1bSJed Brown 
127*c4762a1bSJed Brown    test:
128*c4762a1bSJed Brown       suffix: 2
129*c4762a1bSJed Brown       nsize: 2
130*c4762a1bSJed Brown 
131*c4762a1bSJed Brown TEST*/
132