Actual source code: ex12.c
2: static char help[] = "Tests the use of MatZeroRows() for parallel matrices.\n\
3: This example also tests the use of MatDuplicate() for both MPIAIJ and MPIBAIJ matrices";
5: #include petscmat.h
7: EXTERN PetscErrorCode TestMatZeroRows_Basic(Mat,IS,const PetscScalar[] );
8: EXTERN PetscErrorCode TestMatZeroRows_with_no_allocation(Mat,IS,const PetscScalar[]);
12: int main(int argc,char **args)
13: {
14: Mat A;
15: PetscInt i,j,m = 3,n,I,J,Imax;
16: PetscMPIInt rank,size;
18: PetscScalar v,diag=-4.0;
19: IS is;
21: PetscInitialize(&argc,&args,(char *)0,help);
22: MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
23: MPI_Comm_size(PETSC_COMM_WORLD,&size);
24: n = 2*size;
26: /* create A Square matrix for the five point stencil,YET AGAIN*/
27: MatCreate(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n,&A);
28: MatSetFromOptions(A);
29: for (i=0; i<m; i++) {
30: for (j=2*rank; j<2*rank+2; j++) {
31: v = -1.0; I = j + n*i;
32: if (i>0) {J = I - n; MatSetValues(A,1,&I,1,&J,&v,INSERT_VALUES);}
33: if (i<m-1) {J = I + n; MatSetValues(A,1,&I,1,&J,&v,INSERT_VALUES);}
34: if (j>0) {J = I - 1; MatSetValues(A,1,&I,1,&J,&v,INSERT_VALUES);}
35: if (j<n-1) {J = I + 1; MatSetValues(A,1,&I,1,&J,&v,INSERT_VALUES);}
36: v = 4.0; MatSetValues(A,1,&I,1,&I,&v,INSERT_VALUES);
37: }
38: }
39: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
40: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
42: /* Create AN IS required by MatZeroRows() */
43: Imax = n*rank; if (Imax>= n*m -m - 1) Imax = m*n - m - 1;
44: ISCreateStride(PETSC_COMM_SELF,m,Imax,1,&is);
46: TestMatZeroRows_Basic(A,is,PETSC_NULL);
47: TestMatZeroRows_Basic(A,is,&diag);
49: TestMatZeroRows_with_no_allocation(A,is,PETSC_NULL);
50: TestMatZeroRows_with_no_allocation(A,is,&diag);
52: MatDestroy(A);
54: /* Now Create a rectangular matrix with five point stencil (app)
55: n+size is used so that this dimension is always divisible by size.
56: This way, we can always use bs = size for any number of procs */
57: MatCreate(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,m*n,m*(n+size),&A);
58: MatSetFromOptions(A);
59: for (i=0; i<m; i++) {
60: for (j=2*rank; j<2*rank+2; j++) {
61: v = -1.0; I = j + n*i;
62: if (i>0) {J = I - n; MatSetValues(A,1,&I,1,&J,&v,INSERT_VALUES);}
63: if (i<m-1) {J = I + n; MatSetValues(A,1,&I,1,&J,&v,INSERT_VALUES);}
64: if (j>0) {J = I - 1; MatSetValues(A,1,&I,1,&J,&v,INSERT_VALUES);}
65: if (j<n+size-1) {J = I + 1; MatSetValues(A,1,&I,1,&J,&v,INSERT_VALUES);}
66: v = 4.0; MatSetValues(A,1,&I,1,&I,&v,INSERT_VALUES);
67: }
68: }
69: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
70: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
72: TestMatZeroRows_Basic(A,is,PETSC_NULL);
73: TestMatZeroRows_Basic(A,is,&diag);
75: MatDestroy(A);
76: ISDestroy(is);
77: PetscFinalize();
78: return 0;
79: }
83: PetscErrorCode TestMatZeroRows_Basic(Mat A,IS is,const PetscScalar diag[])
84: {
85: Mat B;
87: PetscTruth keepzeroedrows;
89: /* Now copy A into B, and test it with MatZeroRows() */
90: MatDuplicate(A,MAT_COPY_VALUES,&B);
92: PetscOptionsHasName(PETSC_NULL,"-keep_zeroed_rows",&keepzeroedrows);
93: if (keepzeroedrows) {
94: MatSetOption(B,MAT_KEEP_ZEROED_ROWS);
95: }
97: MatZeroRows(B,is,diag);
98: MatView(B,PETSC_VIEWER_STDOUT_WORLD);
99: MatDestroy(B);
100: return 0;
101: }
105: PetscErrorCode TestMatZeroRows_with_no_allocation(Mat A,IS is,const PetscScalar diag[])
106: {
107: Mat B;
110: /* Now copy A into B, and test it with MatZeroRows() */
111: MatDuplicate(A,MAT_COPY_VALUES,&B);
112: /* Set this flag after assembly. This way, it affects only MatZeroRows() */
113: MatSetOption(B,MAT_NEW_NONZERO_ALLOCATION_ERR);
115: MatZeroRows(B,is,diag);
116: MatView(B,PETSC_VIEWER_STDOUT_WORLD);
117: MatDestroy(B);
118: return 0;
119: }