1 static char help[] = "Test PCFailedReason.\n\n";
2
3 #include <petscksp.h>
4
main(int argc,char ** args)5 int main(int argc, char **args)
6 {
7 Mat A; /* linear system matrix */
8 KSP ksp; /* linear solver context */
9 PC pc; /* preconditioner context */
10 PetscInt i, n = 10, col[3];
11 PetscMPIInt size;
12 PetscScalar value[3], alpha, beta, sx;
13 PetscBool reverse = PETSC_FALSE;
14 KSPConvergedReason reason;
15 PCFailedReason pcreason;
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(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL));
22 PetscCall(PetscOptionsGetBool(NULL, NULL, "-reverse", &reverse, NULL));
23
24 sx = PetscSinReal(n * PETSC_PI / 2 / (n + 1));
25 alpha = 4.0 * sx * sx; /* alpha is the largest eigenvalue of the matrix */
26 beta = 4.0;
27
28 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
29 Create the matrix
30 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
31 PetscCall(MatCreate(PETSC_COMM_WORLD, &A));
32 PetscCall(MatSetSizes(A, PETSC_DECIDE, PETSC_DECIDE, n, n));
33 PetscCall(MatSetFromOptions(A));
34 PetscCall(MatSetUp(A));
35
36 value[0] = -1.0;
37 value[1] = 2.0;
38 value[2] = -1.0;
39 for (i = 1; i < n - 1; i++) {
40 col[0] = i - 1;
41 col[1] = i;
42 col[2] = i + 1;
43 PetscCall(MatSetValues(A, 1, &i, 3, col, value, INSERT_VALUES));
44 }
45 i = n - 1;
46 col[0] = n - 2;
47 col[1] = n - 1;
48 PetscCall(MatSetValues(A, 1, &i, 2, col, value, INSERT_VALUES));
49 i = 0;
50 col[0] = 0;
51 col[1] = 1;
52 value[0] = 2.0;
53 value[1] = -1.0;
54 PetscCall(MatSetValues(A, 1, &i, 2, col, value, INSERT_VALUES));
55 PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
56 PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
57
58 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
59 Create the linear solver and set various options
60 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
61 PetscCall(KSPCreate(PETSC_COMM_WORLD, &ksp));
62 PetscCall(KSPSetOperators(ksp, A, A));
63 PetscCall(MatShift(A, reverse ? -alpha : -beta));
64 PetscCall(KSPGetPC(ksp, &pc));
65 PetscCall(PCSetType(pc, PCLU));
66 PetscCall(KSPSetFromOptions(ksp));
67
68 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
69 Factorize first matrix
70 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
71 PetscCall(PetscPrintf(PETSC_COMM_WORLD, "First matrix\n"));
72 PetscCall(KSPSetUp(ksp));
73 PetscCall(KSPGetConvergedReason(ksp, &reason));
74 if (reason < 0) {
75 PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)ksp)), PETSC_VIEWER_DEFAULT));
76 PetscCall(KSPConvergedReasonView(ksp, PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)ksp))));
77 PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)ksp))));
78 } else {
79 PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Success!\n"));
80 }
81
82 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
83 Factorize second matrix
84 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
85 PetscCall(MatShift(A, reverse ? alpha - beta : beta - alpha));
86 PetscCall(KSPSetOperators(ksp, A, A));
87
88 PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Second matrix\n"));
89 PetscCall(KSPSetUp(ksp));
90 PetscCall(KSPGetConvergedReason(ksp, &reason));
91 if (reason < 0) {
92 PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)ksp)), PETSC_VIEWER_DEFAULT));
93 PetscCall(KSPConvergedReasonView(ksp, PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)ksp))));
94 PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)ksp))));
95 } else {
96 PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Success!\n"));
97 PetscCall(PCGetFailedReason(pc, &pcreason));
98 PetscCall(PetscPrintf(PETSC_COMM_WORLD, "PC failed reason is %s\n", PCFailedReasons[pcreason]));
99 }
100
101 /*
102 Free work space.
103 */
104 PetscCall(MatDestroy(&A));
105 PetscCall(KSPDestroy(&ksp));
106
107 PetscCall(PetscFinalize());
108 return 0;
109 }
110
111 /*TEST
112
113 test:
114 args: -reverse
115
116 test:
117 suffix: 2
118 args: -reverse -pc_type cholesky
119
120 TEST*/
121