Actual source code: ex71.c
petsc-3.4.2 2013-07-02

      2: static char help[] = "Passes a sparse matrix to MATLAB.\n\n";

      4: #include <petscmat.h>

      8: int main(int argc,char **args)
      9: {
     11:   PetscInt       m   = 4,n = 5,i,j,II,J;
     12:   PetscScalar    one = 1.0,v;
     13:   Vec            x;
     14:   Mat            A;

     16:   PetscInitialize(&argc,&args,(char*)0,help);
     17:   PetscOptionsGetInt(NULL,"-m",&m,NULL);
     18:   PetscOptionsGetInt(NULL,"-n",&n,NULL);

     20:   MatCreate(PETSC_COMM_WORLD,&A);
     21:   MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n);
     22:   MatSetFromOptions(A);

     24:   for (i=0; i<m; i++) {
     25:     for (j=0; j<n; j++) {
     26:       v = -1.0;  II = j + n*i;
     27:       if (i>0)   {J = II - n; MatSetValues(A,1,&II,1,&J,&v,INSERT_VALUES);}
     28:       if (i<m-1) {J = II + n; MatSetValues(A,1,&II,1,&J,&v,INSERT_VALUES);}
     29:       if (j>0)   {J = II - 1; MatSetValues(A,1,&II,1,&J,&v,INSERT_VALUES);}
     30:       if (j<n-1) {J = II + 1; MatSetValues(A,1,&II,1,&J,&v,INSERT_VALUES);}
     31:       v = 4.0; MatSetValues(A,1,&II,1,&II,&v,INSERT_VALUES);
     32:     }
     33:   }
     34:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
     35:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
     36: #if defined(PETSC_USE_SOCKET_VIEWER)
     37:   MatView(A,PETSC_VIEWER_SOCKET_WORLD);
     38: #endif
     39:   VecCreateSeq(PETSC_COMM_SELF,m,&x);
     40:   VecSet(x,one);
     41: #if defined(PETSC_USE_SOCKET_VIEWER)
     42:   VecView(x,PETSC_VIEWER_SOCKET_WORLD);
     43: #endif

     45:   PetscSleep(30);

     47:   VecDestroy(&x);
     48:   MatDestroy(&A);
     49:   PetscFinalize();
     50:   return 0;
     51: }