1 static char help[] = "Tests MatNorm(), MatLUFactor(), MatSolve() and MatSolveAdd().\n\n";
2
3 #include <petscmat.h>
4
main(int argc,char ** args)5 int main(int argc, char **args)
6 {
7 Mat C;
8 PetscInt i, j, m = 3, n = 3, Ii, J;
9 PetscBool flg;
10 PetscScalar v;
11 IS perm, iperm;
12 Vec x, u, b, y;
13 PetscReal norm, tol = PETSC_SMALL;
14 MatFactorInfo info;
15 PetscMPIInt size;
16
17 PetscFunctionBeginUser;
18 PetscCall(PetscInitialize(&argc, &args, NULL, help));
19 PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
20 PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "This is a uniprocessor example only!");
21 PetscCall(MatCreate(PETSC_COMM_WORLD, &C));
22 PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n));
23 PetscCall(MatSetFromOptions(C));
24 PetscCall(MatSetUp(C));
25 PetscCall(PetscOptionsHasName(NULL, NULL, "-symmetric", &flg));
26 if (flg) { /* Treat matrix as symmetric only if we set this flag */
27 PetscCall(MatSetOption(C, MAT_SYMMETRIC, PETSC_TRUE));
28 PetscCall(MatSetOption(C, MAT_SYMMETRY_ETERNAL, PETSC_TRUE));
29 }
30
31 /* Create the matrix for the five point stencil, YET AGAIN */
32 for (i = 0; i < m; i++) {
33 for (j = 0; j < n; j++) {
34 v = -1.0;
35 Ii = j + n * i;
36 if (i > 0) {
37 J = Ii - n;
38 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
39 }
40 if (i < m - 1) {
41 J = Ii + n;
42 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
43 }
44 if (j > 0) {
45 J = Ii - 1;
46 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
47 }
48 if (j < n - 1) {
49 J = Ii + 1;
50 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
51 }
52 v = 4.0;
53 PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
54 }
55 }
56 PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
57 PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
58 PetscCall(MatGetOrdering(C, MATORDERINGRCM, &perm, &iperm));
59 PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD));
60 PetscCall(ISView(perm, PETSC_VIEWER_STDOUT_SELF));
61 PetscCall(VecCreateSeq(PETSC_COMM_SELF, m * n, &u));
62 PetscCall(VecSet(u, 1.0));
63 PetscCall(VecDuplicate(u, &x));
64 PetscCall(VecDuplicate(u, &b));
65 PetscCall(VecDuplicate(u, &y));
66 PetscCall(MatMult(C, u, b));
67 PetscCall(VecCopy(b, y));
68 PetscCall(VecScale(y, 2.0));
69
70 PetscCall(MatNorm(C, NORM_FROBENIUS, &norm));
71 PetscCall(PetscPrintf(PETSC_COMM_SELF, "Frobenius norm of matrix %g\n", (double)norm));
72 PetscCall(MatNorm(C, NORM_1, &norm));
73 PetscCall(PetscPrintf(PETSC_COMM_SELF, "One norm of matrix %g\n", (double)norm));
74 PetscCall(MatNorm(C, NORM_INFINITY, &norm));
75 PetscCall(PetscPrintf(PETSC_COMM_SELF, "Infinity norm of matrix %g\n", (double)norm));
76
77 PetscCall(MatFactorInfoInitialize(&info));
78 info.fill = 2.0;
79 info.dtcol = 0.0;
80 info.zeropivot = 1.e-14;
81 info.pivotinblocks = 1.0;
82
83 PetscCall(MatLUFactor(C, perm, iperm, &info));
84
85 /* Test MatSolve */
86 PetscCall(MatSolve(C, b, x));
87 PetscCall(VecView(b, PETSC_VIEWER_STDOUT_SELF));
88 PetscCall(VecView(x, PETSC_VIEWER_STDOUT_SELF));
89 PetscCall(VecAXPY(x, -1.0, u));
90 PetscCall(VecNorm(x, NORM_2, &norm));
91 if (norm > tol) PetscCall(PetscPrintf(PETSC_COMM_SELF, "MatSolve: Norm of error %g\n", (double)norm));
92
93 /* Test MatSolveAdd */
94 PetscCall(MatSolveAdd(C, b, y, x));
95 PetscCall(VecAXPY(x, -1.0, y));
96 PetscCall(VecAXPY(x, -1.0, u));
97 PetscCall(VecNorm(x, NORM_2, &norm));
98 if (norm > tol) PetscCall(PetscPrintf(PETSC_COMM_SELF, "MatSolveAdd(): Norm of error %g\n", (double)norm));
99
100 PetscCall(ISDestroy(&perm));
101 PetscCall(ISDestroy(&iperm));
102 PetscCall(VecDestroy(&u));
103 PetscCall(VecDestroy(&y));
104 PetscCall(VecDestroy(&b));
105 PetscCall(VecDestroy(&x));
106 PetscCall(MatDestroy(&C));
107 PetscCall(PetscFinalize());
108 return 0;
109 }
110
111 /*TEST
112
113 test:
114
115 TEST*/
116