Actual source code: ex9.c
2: static char help[] = "Tests MPI parallel matrix creation.\n\n";
4: #include <petscmat.h>
8: int main(int argc,char **args)
9: {
10: Mat C;
11: MatInfo info;
12: PetscMPIInt rank,size;
13: PetscInt i,j,m = 3,n = 2,low,high,iglobal;
14: PetscInt Ii,J,ldim;
16: PetscBool flg;
17: PetscScalar v,one = 1.0;
18: Vec u,b;
20: PetscInitialize(&argc,&args,(char *)0,help);
21: MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
22: MPI_Comm_size(PETSC_COMM_WORLD,&size);
23: n = 2*size;
25: MatCreate(PETSC_COMM_WORLD,&C);
26: MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n);
27: MatSetFromOptions(C);
29: /* Create the matrix for the five point stencil, YET AGAIN */
30: for (i=0; i<m; i++) {
31: for (j=2*rank; j<2*rank+2; j++) {
32: v = -1.0; Ii = j + n*i;
33: if (i>0) {J = Ii - n; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
34: if (i<m-1) {J = Ii + n; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
35: if (j>0) {J = Ii - 1; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
36: if (j<n-1) {J = Ii + 1; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
37: v = 4.0; MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES);
38: }
39: }
41: /* Add extra elements (to illustrate variants of MatGetInfo) */
42: Ii = n; J = n-2; v = 100.0;
43: MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);
44: Ii = n-2; J = n; v = 100.0;
45: MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);
47: MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
48: MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
50: /* Form vectors */
51: VecCreate(PETSC_COMM_WORLD,&u);
52: VecSetSizes(u,PETSC_DECIDE,m*n);
53: VecSetFromOptions(u);
54: VecDuplicate(u,&b);
55: VecGetLocalSize(u,&ldim);
56: VecGetOwnershipRange(u,&low,&high);
57: for (i=0; i<ldim; i++) {
58: iglobal = i + low;
59: v = one*((PetscReal)i) + 100.0*rank;
60: VecSetValues(u,1,&iglobal,&v,INSERT_VALUES);
61: }
62: VecAssemblyBegin(u);
63: VecAssemblyEnd(u);
65: MatMult(C,u,b);
67: VecView(u,PETSC_VIEWER_STDOUT_WORLD);
68: VecView(b,PETSC_VIEWER_STDOUT_WORLD);
70: VecDestroy(&u);
71: VecDestroy(&b);
73: PetscOptionsHasName(PETSC_NULL,"-view_info",&flg);
74: if (flg) {PetscViewerSetFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO);}
75: MatView(C,PETSC_VIEWER_STDOUT_WORLD);
77: MatGetInfo(C,MAT_GLOBAL_SUM,&info);
78: PetscPrintf(PETSC_COMM_WORLD,"matrix information (global sums):\n\
79: nonzeros = %D, allocated nonzeros = %D\n",(PetscInt)info.nz_used,(PetscInt)info.nz_allocated);
80: MatGetInfo (C,MAT_GLOBAL_MAX,&info);
81: PetscPrintf(PETSC_COMM_WORLD,"matrix information (global max):\n\
82: nonzeros = %D, allocated nonzeros = %D\n",(PetscInt)info.nz_used,(PetscInt)info.nz_allocated);
84: MatDestroy(&C);
85: PetscFinalize();
86: return 0;
87: }