1 static char help[] = "Tests the use of MatSolveTranspose().\n\n";
2
3 #include <petscmat.h>
4
main(int argc,char ** args)5 int main(int argc, char **args)
6 {
7 Mat C, A;
8 PetscInt i, j, m = 5, n = 5, Ii, J;
9 PetscScalar v, five = 5.0, one = 1.0;
10 IS isrow, row, col;
11 Vec x, u, b;
12 PetscReal norm;
13 MatFactorInfo info;
14
15 PetscFunctionBeginUser;
16 PetscCall(PetscInitialize(&argc, &args, NULL, help));
17 PetscCall(PetscOptionsGetInt(NULL, NULL, "-m", &m, NULL));
18 PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL));
19
20 PetscCall(MatCreateSeqAIJ(PETSC_COMM_SELF, m * n, m * n, 5, NULL, &C));
21 PetscCall(MatSetUp(C));
22
23 /* create the matrix for the five point stencil, YET AGAIN*/
24 for (i = 0; i < m; i++) {
25 for (j = 0; j < n; j++) {
26 v = -1.0;
27 Ii = j + n * i;
28 if (i > 0) {
29 J = Ii - n;
30 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
31 }
32 if (i < m - 1) {
33 J = Ii + n;
34 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
35 }
36 if (j > 0) {
37 J = Ii - 1;
38 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
39 }
40 if (j < n - 1) {
41 J = Ii + 1;
42 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
43 }
44 v = 4.0;
45 PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
46 }
47 }
48 PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
49 PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
50
51 PetscCall(ISCreateStride(PETSC_COMM_SELF, (m * n) / 2, 0, 2, &isrow));
52 PetscCall(MatZeroRowsIS(C, isrow, five, 0, 0));
53
54 PetscCall(VecCreateSeq(PETSC_COMM_SELF, m * n, &u));
55 PetscCall(VecDuplicate(u, &x));
56 PetscCall(VecDuplicate(u, &b));
57 PetscCall(VecSet(u, one));
58
59 PetscCall(MatMultTranspose(C, u, b));
60
61 /* Set default ordering to be Quotient Minimum Degree; also read
62 orderings from the options database */
63 PetscCall(MatGetOrdering(C, MATORDERINGQMD, &row, &col));
64
65 PetscCall(MatFactorInfoInitialize(&info));
66 PetscCall(MatGetFactor(C, MATSOLVERPETSC, MAT_FACTOR_LU, &A));
67 PetscCall(MatLUFactorSymbolic(A, C, row, col, &info));
68 PetscCall(MatLUFactorNumeric(A, C, &info));
69 PetscCall(MatSolveTranspose(A, b, x));
70
71 PetscCall(ISView(row, PETSC_VIEWER_STDOUT_SELF));
72 PetscCall(VecAXPY(x, -1.0, u));
73 PetscCall(VecNorm(x, NORM_2, &norm));
74 PetscCall(PetscPrintf(PETSC_COMM_SELF, "Norm of error %g\n", (double)norm));
75
76 PetscCall(ISDestroy(&row));
77 PetscCall(ISDestroy(&col));
78 PetscCall(ISDestroy(&isrow));
79 PetscCall(VecDestroy(&u));
80 PetscCall(VecDestroy(&x));
81 PetscCall(VecDestroy(&b));
82 PetscCall(MatDestroy(&C));
83 PetscCall(MatDestroy(&A));
84 PetscCall(PetscFinalize());
85 return 0;
86 }
87
88 /*TEST
89
90 test:
91
92 TEST*/
93