Actual source code: ex64.c
petsc-3.4.2 2013-07-02

      2: static char help[] = "Saves 4by4 block matrix.\n\n";

      4: #include <petscmat.h>

      8: int main(int argc,char **args)
      9: {
     10:   Mat            A;
     11:   PetscInt       i,j;
     13:   PetscMPIInt    size;
     14:   PetscViewer    fd;
     15:   PetscScalar    values[16],one = 1.0;
     16:   Vec            x;

     18:   PetscInitialize(&argc,&args,(char*)0,help);
     19:   MPI_Comm_size(PETSC_COMM_WORLD,&size);
     20:   if (size > 1) SETERRQ(PETSC_COMM_WORLD,1,"Can only run on one processor");

     22:   /*
     23:      Open binary file.  Note that we use FILE_MODE_WRITE to indicate
     24:      writing to this file.
     25:   */
     26:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,"4by4",FILE_MODE_WRITE,&fd);

     28:   MatCreateSeqBAIJ(PETSC_COMM_WORLD,4,12,12,0,0,&A);

     30:   for (i=0; i<16; i++) values[i] = i;
     31:   for (i=0; i<4; i++) values[4*i+i] += 5;
     32:   i    = 0; j = 0;
     33:   MatSetValuesBlocked(A,1,&i,1,&j,values,INSERT_VALUES);

     35:   for (i=0; i<16; i++) values[i] = i;
     36:   i    = 0; j = 2;
     37:   MatSetValuesBlocked(A,1,&i,1,&j,values,INSERT_VALUES);

     39:   for (i=0; i<16; i++) values[i] = i;
     40:   i    = 1; j = 0;
     41:   MatSetValuesBlocked(A,1,&i,1,&j,values,INSERT_VALUES);

     43:   for (i=0; i<16; i++) values[i] = i;for (i=0; i<4; i++) values[4*i+i] += 6;
     44:   i    = 1; j = 1;
     45:   MatSetValuesBlocked(A,1,&i,1,&j,values,INSERT_VALUES);

     47:   for (i=0; i<16; i++) values[i] = i;
     48:   i    = 2; j = 0;
     49:   MatSetValuesBlocked(A,1,&i,1,&j,values,INSERT_VALUES);

     51:   for (i=0; i<16; i++) values[i] = i;for (i=0; i<4; i++) values[4*i+i] += 7;
     52:   i    = 2; j = 2;
     53:   MatSetValuesBlocked(A,1,&i,1,&j,values,INSERT_VALUES);

     55:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
     56:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
     57:   MatView(A,fd);
     58:   MatDestroy(&A);

     60:   VecCreateSeq(PETSC_COMM_WORLD,12,&x);
     61:   VecSet(x,one);
     62:   VecView(x,fd);
     63:   VecDestroy(&x);

     65:   PetscViewerDestroy(&fd);
     66:   PetscFinalize();
     67:   return 0;
     68: }