xref: /petsc/src/mat/tests/ex168.c (revision d5b43468fb8780a8feea140ccd6fa3e6a50411cc)
1 
2 static char help[] = "Tests external Clique direct solvers. Simplified from ex130.c\n\
3 Example: mpiexec -n <np> ./ex168 -f <matrix binary file> \n\n";
4 
5 #include <petscmat.h>
6 
7 int main(int argc, char **args)
8 {
9   Mat           A, F;
10   Vec           u, x, b;
11   PetscMPIInt   rank, size;
12   PetscInt      m, n, nfact;
13   PetscReal     norm, tol = 1.e-12, Anorm;
14   IS            perm, iperm;
15   MatFactorInfo info;
16   PetscBool     flg, testMatSolve = PETSC_TRUE;
17   PetscViewer   fd;                       /* viewer */
18   char          file[PETSC_MAX_PATH_LEN]; /* input file name */
19 
20   PetscFunctionBeginUser;
21   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
22   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
23   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
24 
25   /* Determine file from which we read the matrix A */
26   PetscCall(PetscOptionsGetString(NULL, NULL, "-f", file, sizeof(file), &flg));
27   PetscCheck(flg, PETSC_COMM_WORLD, PETSC_ERR_USER, "Must indicate binary file with the -f option");
28 
29   /* Load matrix A */
30   PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, file, FILE_MODE_READ, &fd));
31   PetscCall(MatCreate(PETSC_COMM_WORLD, &A));
32   PetscCall(MatLoad(A, fd));
33   PetscCall(VecCreate(PETSC_COMM_WORLD, &b));
34   PetscCall(VecLoad(b, fd));
35   PetscCall(PetscViewerDestroy(&fd));
36   PetscCall(MatGetLocalSize(A, &m, &n));
37   PetscCheck(m == n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "This example is not intended for rectangular matrices (%d, %d)", m, n);
38   PetscCall(MatNorm(A, NORM_INFINITY, &Anorm));
39 
40   /* Create vectors */
41   PetscCall(VecDuplicate(b, &x));
42   PetscCall(VecDuplicate(x, &u)); /* save the true solution */
43 
44   /* Test Cholesky Factorization */
45   PetscCall(MatGetOrdering(A, MATORDERINGNATURAL, &perm, &iperm));
46 
47   if (rank == 0) printf(" Clique Cholesky:\n");
48   PetscCall(MatGetFactor(A, MATSOLVERCLIQUE, MAT_FACTOR_CHOLESKY, &F));
49 
50   info.fill = 5.0;
51   PetscCall(MatCholeskyFactorSymbolic(F, A, perm, &info));
52 
53   for (nfact = 0; nfact < 1; nfact++) {
54     if (rank == 0) printf(" %d-the Cholesky numfactorization \n", nfact);
55     PetscCall(MatCholeskyFactorNumeric(F, A, &info));
56 
57     /* Test MatSolve() */
58     if (testMatSolve && nfact == 2) {
59       PetscCall(MatSolve(F, b, x));
60 
61       /* Check the residual */
62       PetscCall(MatMult(A, x, u));
63       PetscCall(VecAXPY(u, -1.0, b));
64       PetscCall(VecNorm(u, NORM_INFINITY, &norm));
65       /* if (norm > tol) { */
66       if (rank == 0) PetscCall(PetscPrintf(PETSC_COMM_SELF, "MatSolve: rel residual %g/%g = %g, LU numfact %d\n", norm, Anorm, norm / Anorm, nfact));
67       /*} */
68     }
69   }
70 
71   /* Free data structures */
72   PetscCall(MatDestroy(&A));
73   PetscCall(MatDestroy(&F));
74   PetscCall(ISDestroy(&perm));
75   PetscCall(ISDestroy(&iperm));
76   PetscCall(VecDestroy(&x));
77   PetscCall(VecDestroy(&b));
78   PetscCall(VecDestroy(&u));
79   PetscCall(PetscFinalize());
80   return 0;
81 }
82