Actual source code: ex33.c

  1: /*$Id: ex33.c,v 1.23 2001/09/11 16:32:50 bsmith Exp $*/

  3: static char help[] = "Writes a matrix using the PETSc sparse format. Input arguments are:\n\
  4:    -fout <file> : output file name\n\n";

 6:  #include petscmat.h

 10: int main(int argc,char **args)
 11: {
 12:   Mat         A;
 13:   Vec         b;
 14:   char        fileout[128];
 15:   int         i,j,m = 6,n = 6,N = 36,ierr,I,J;
 16:   PetscScalar val,v;
 17:   PetscViewer view;

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

 21:   MatCreate(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,N,N,&A);
 22:   MatSetFromOptions(A);
 23:   for (i=0; i<m; i++) {
 24:     for (j=0; j<n; j++) {
 25:       v = -1.0;  I = j + n*i;
 26:       if (i>0)   {J = I - n; MatSetValues(A,1,&I,1,&J,&v,INSERT_VALUES);}
 27:       if (i<m-1) {J = I + n; MatSetValues(A,1,&I,1,&J,&v,INSERT_VALUES);}
 28:       if (j>0)   {J = I - 1; MatSetValues(A,1,&I,1,&J,&v,INSERT_VALUES);}
 29:       if (j<n-1) {J = I + 1; MatSetValues(A,1,&I,1,&J,&v,INSERT_VALUES);}
 30:       v = 4.0; MatSetValues(A,1,&I,1,&I,&v,INSERT_VALUES);
 31:     }
 32:   }
 33:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
 34:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

 36:   VecCreate(PETSC_COMM_WORLD,&b);
 37:   VecSetSizes(b,PETSC_DECIDE,N);
 38:   VecSetFromOptions(b);
 39:   for (i=0; i<N; i++) {
 40:     val = i + 1;
 41:     VecSetValues(b,1,&i,&val,INSERT_VALUES);
 42:   }
 43:   VecAssemblyBegin(b);
 44:   VecAssemblyEnd(b);

 46:   PetscOptionsGetString(PETSC_NULL,"-fout",fileout,127,PETSC_NULL);
 47:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,fileout,PETSC_BINARY_CREATE,&view);
 48:   MatView(A,view);
 49:   VecView(b,view);
 50:   PetscViewerDestroy(view);

 52:   VecDestroy(b);
 53:   MatDestroy(A);

 55:   PetscFinalize();
 56:   return 0;
 57: }