2: static char help[] = "Reads a matrix and vector from a file and writes to another. Input options:\n\
  3:   -fin <input_file> : file to load.  For an example of a 5X5 5-pt. stencil,\n\
  4:                       use the file matbinary.ex.\n\
  5:   -fout <output_file> : file for saving output matrix and vector\n\n";

 7:  #include petscmat.h

 11: int main(int argc,char **args)
 12: {
 14:   PetscTruth  flg;
 15:   Vec         x;
 16:   Mat         A;
 17:   char        file[256];
 18:   PetscViewer fd;

 20:   PetscInitialize(&argc,&args,(char *)0,help);

 22:   /* Read matrix and RHS */
 23:   PetscOptionsGetString(PETSC_NULL,"-fin",file,255,&flg);
 24:   if (!flg) SETERRQ(1,help);
 25:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,file,FILE_MODE_READ,&fd);
 26:   MatLoad(fd,MATSEQAIJ,&A);
 27:   VecLoad(fd,PETSC_NULL,&x);
 28:   PetscViewerDestroy(fd);

 30:   /* Write matrix and vector */
 31:   PetscOptionsGetString(PETSC_NULL,"-fout",file,255,&flg);
 32:   if (!flg) SETERRQ(1,help);
 33:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,file,FILE_MODE_WRITE,&fd);
 34:   MatView(A,fd);
 35:   VecView(x,fd);

 37:   /* Free data structures */
 38:   MatDestroy(A);
 39:   VecDestroy(x);
 40:   PetscViewerDestroy(fd);

 42:   PetscFinalize();
 43:   return 0;
 44: }