2: static char help[] = "Tests MatMult() on MatLoad() matrix \n\n";

  4:  #include <petscmat.h>

  6: int main(int argc,char **args)
  7: {
  8:   Mat            A;
  9:   Vec            x,b;
 11:   PetscViewer    fd;              /* viewer */
 12:   char           file[PETSC_MAX_PATH_LEN]; /* input file name */
 13:   PetscBool      flg;

 15:   PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
 16:   /* Determine file from which we read the matrix A */
 17:   PetscOptionsGetString(NULL,NULL,"-f",file,PETSC_MAX_PATH_LEN,&flg);
 18:   if (!flg) SETERRQ(PETSC_COMM_WORLD,1,"Must indicate binary file with the -f option");

 20:   /* Load matrix A */
 21:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,file,FILE_MODE_READ,&fd);
 22:   MatCreate(PETSC_COMM_WORLD,&A);
 23:   MatLoad(A,fd);
 24:   flg  = PETSC_FALSE;
 25:   VecCreate(PETSC_COMM_WORLD,&x);
 26:   PetscOptionsGetString(NULL,NULL,"-vec",file,PETSC_MAX_PATH_LEN,&flg);
 27:   if (flg) {
 28:     if (file[0] == '0') {
 29:       PetscInt    m;
 30:       PetscScalar one = 1.0;
 31:       PetscInfo(0,"Using vector of ones for RHS\n");
 32:       MatGetLocalSize(A,&m,NULL);
 33:       VecSetSizes(x,m,PETSC_DECIDE);
 34:       VecSetFromOptions(x);
 35:       VecSet(x,one);
 36:     }
 37:   } else {
 38:     VecLoad(x,fd);
 39:     PetscViewerDestroy(&fd);
 40:   }
 41:   VecDuplicate(x,&b);
 42:   MatMult(A,x,b);

 44:   /* Print (for testing only) */
 45:   MatView(A,0);
 46:   VecView(b,0);
 47:   /* Free data structures */
 48:   MatDestroy(&A);
 49:   VecDestroy(&x);
 50:   VecDestroy(&b);
 51:   PetscFinalize();
 52:   return ierr;
 53: }