xref: /petsc/src/mat/tests/ex168.c (revision 8fb5bd83c3955fefcf33a54e3bb66920a9fa884b)
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   PetscCall(PetscInitialize(&argc,&args,(char*)0,help));
21   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
22   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
23 
24   /* Determine file from which we read the matrix A */
25   PetscCall(PetscOptionsGetString(NULL,NULL,"-f",file,sizeof(file),&flg));
26   PetscCheck(flg,PETSC_COMM_WORLD,PETSC_ERR_USER,"Must indicate binary file with the -f option");
27 
28   /* Load matrix A */
29   PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD,file,FILE_MODE_READ,&fd));
30   PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
31   PetscCall(MatLoad(A,fd));
32   PetscCall(VecCreate(PETSC_COMM_WORLD,&b));
33   PetscCall(VecLoad(b,fd));
34   PetscCall(PetscViewerDestroy(&fd));
35   PetscCall(MatGetLocalSize(A,&m,&n));
36   PetscCheck(m == n,PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ, "This example is not intended for rectangular matrices (%d, %d)", m, n);
37   PetscCall(MatNorm(A,NORM_INFINITY,&Anorm));
38 
39   /* Create vectors */
40   PetscCall(VecDuplicate(b,&x));
41   PetscCall(VecDuplicate(x,&u)); /* save the true solution */
42 
43   /* Test Cholesky Factorization */
44   PetscCall(MatGetOrdering(A,MATORDERINGNATURAL,&perm,&iperm));
45 
46   if (rank == 0) printf(" Clique Cholesky:\n");
47   PetscCall(MatGetFactor(A,MATSOLVERCLIQUE,MAT_FACTOR_CHOLESKY,&F));
48 
49   info.fill = 5.0;
50   PetscCall(MatCholeskyFactorSymbolic(F,A,perm,&info));
51 
52   for (nfact = 0; nfact < 1; nfact++) {
53     if (rank == 0) printf(" %d-the Cholesky numfactorization \n",nfact);
54     PetscCall(MatCholeskyFactorNumeric(F,A,&info));
55 
56     /* Test MatSolve() */
57     if (testMatSolve && nfact == 2) {
58       PetscCall(MatSolve(F,b,x));
59 
60       /* Check the residual */
61       PetscCall(MatMult(A,x,u));
62       PetscCall(VecAXPY(u,-1.0,b));
63       PetscCall(VecNorm(u,NORM_INFINITY,&norm));
64       /* if (norm > tol) { */
65       if (rank == 0) {
66         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 
72   /* Free data structures */
73   PetscCall(MatDestroy(&A));
74   PetscCall(MatDestroy(&F));
75   PetscCall(ISDestroy(&perm));
76   PetscCall(ISDestroy(&iperm));
77   PetscCall(VecDestroy(&x));
78   PetscCall(VecDestroy(&b));
79   PetscCall(VecDestroy(&u));
80   PetscCall(PetscFinalize());
81   return 0;
82 }
83