Actual source code: ex9.c
petsc-3.3-p6 2013-02-11
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);
28: MatSetUp(C);
30: /* Create the matrix for the five point stencil, YET AGAIN */
31: for (i=0; i<m; i++) {
32: for (j=2*rank; j<2*rank+2; j++) {
33: v = -1.0; Ii = j + n*i;
34: if (i>0) {J = Ii - n; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
35: if (i<m-1) {J = Ii + n; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
36: if (j>0) {J = Ii - 1; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
37: if (j<n-1) {J = Ii + 1; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
38: v = 4.0; MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES);
39: }
40: }
42: /* Add extra elements (to illustrate variants of MatGetInfo) */
43: Ii = n; J = n-2; v = 100.0;
44: MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);
45: Ii = n-2; J = n; v = 100.0;
46: MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);
48: MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
49: MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
51: /* Form vectors */
52: VecCreate(PETSC_COMM_WORLD,&u);
53: VecSetSizes(u,PETSC_DECIDE,m*n);
54: VecSetFromOptions(u);
55: VecDuplicate(u,&b);
56: VecGetLocalSize(u,&ldim);
57: VecGetOwnershipRange(u,&low,&high);
58: for (i=0; i<ldim; i++) {
59: iglobal = i + low;
60: v = one*((PetscReal)i) + 100.0*rank;
61: VecSetValues(u,1,&iglobal,&v,INSERT_VALUES);
62: }
63: VecAssemblyBegin(u);
64: VecAssemblyEnd(u);
66: MatMult(C,u,b);
68: VecView(u,PETSC_VIEWER_STDOUT_WORLD);
69: VecView(b,PETSC_VIEWER_STDOUT_WORLD);
71: VecDestroy(&u);
72: VecDestroy(&b);
74: PetscOptionsHasName(PETSC_NULL,"-view_info",&flg);
75: if (flg) {PetscViewerSetFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO);}
76: MatView(C,PETSC_VIEWER_STDOUT_WORLD);
78: MatGetInfo(C,MAT_GLOBAL_SUM,&info);
79: PetscPrintf(PETSC_COMM_WORLD,"matrix information (global sums):\n\
80: nonzeros = %D, allocated nonzeros = %D\n",(PetscInt)info.nz_used,(PetscInt)info.nz_allocated);
81: MatGetInfo (C,MAT_GLOBAL_MAX,&info);
82: PetscPrintf(PETSC_COMM_WORLD,"matrix information (global max):\n\
83: nonzeros = %D, allocated nonzeros = %D\n",(PetscInt)info.nz_used,(PetscInt)info.nz_allocated);
85: MatDestroy(&C);
86: PetscFinalize();
87: return 0;
88: }