Actual source code: ex168.c


  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";

  5: #include <petscmat.h>

  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 */

 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));

 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");

 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));

 40:   /* Create vectors */
 41:   PetscCall(VecDuplicate(b, &x));
 42:   PetscCall(VecDuplicate(x, &u)); /* save the true solution */

 44:   /* Test Cholesky Factorization */
 45:   PetscCall(MatGetOrdering(A, MATORDERINGNATURAL, &perm, &iperm));

 47:   if (rank == 0) printf(" Clique Cholesky:\n");
 48:   PetscCall(MatGetFactor(A, MATSOLVERCLIQUE, MAT_FACTOR_CHOLESKY, &F));

 50:   info.fill = 5.0;
 51:   PetscCall(MatCholeskyFactorSymbolic(F, A, perm, &info));

 53:   for (nfact = 0; nfact < 1; nfact++) {
 54:     if (rank == 0) printf(" %d-the Cholesky numfactorization \n", nfact);
 55:     PetscCall(MatCholeskyFactorNumeric(F, A, &info));

 57:     /* Test MatSolve() */
 58:     if (testMatSolve && nfact == 2) {
 59:       PetscCall(MatSolve(F, b, x));

 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:   }

 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: }