2: static char help[] = "Tests MatDenseGetArray() and MatView_SeqDense_Binary(), MatView_MPIDense_Binary().\n\n";

  4:  #include <petscmat.h>
  5:  #include <petscviewer.h>

  7: int main(int argc,char **args)
  8: {
  9:   Mat            A;
 10:   PetscInt       i,j,m = 3,n = 2,rstart,rend;
 12:   PetscScalar    v,*array;
 13:   PetscViewer    view;

 15:   PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
 16:   /*
 17:       Create a parallel dense matrix shared by all processors
 18:   */
 19:   MatCreateDense(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,m,n,NULL,&A);

 21:   /*
 22:      Set values into the matrix
 23:   */
 24:   for (i=0; i<m; i++) {
 25:     for (j=0; j<n; j++) {
 26:       v = 9.0/(i+j+1); MatSetValues(A,1,&i,1,&j,&v,INSERT_VALUES);
 27:     }
 28:   }
 29:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
 30:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

 32:   /*
 33:        Print the matrix to the screen
 34:   */
 35:   MatView(A,PETSC_VIEWER_STDOUT_WORLD);


 38:   /*
 39:       Print the local portion of the matrix to the screen
 40:   */
 41:   MatDenseGetArray(A,&array);
 42:   MatGetOwnershipRange(A,&rstart,&rend);
 43:   for (i=rstart; i<rend; i++) {
 44:     for (j=0; j<n; j++) {
 45:       PetscSynchronizedPrintf(PETSC_COMM_WORLD,"%6.4e ",(double)PetscRealPart(array[j*(rend-rstart)+i-rstart]));
 46:     }
 47:     PetscSynchronizedPrintf(PETSC_COMM_WORLD,"\n");
 48:   }
 49:   PetscSynchronizedFlush(PETSC_COMM_WORLD,PETSC_STDOUT);
 50:   MatDenseRestoreArray(A,&array);

 52:   /*
 53:       Store the binary matrix to a file
 54:   */
 55:   PetscViewerBinaryOpen(PETSC_COMM_WORLD, "matrix.dat", FILE_MODE_WRITE, &view);
 56:   PetscViewerPushFormat(view,PETSC_VIEWER_NATIVE);
 57:   MatView(A,view);
 58:   PetscViewerPopFormat(view);
 59:   PetscViewerDestroy(&view);
 60:   MatDestroy(&A);

 62:   /*
 63:      Now reload the matrix and view it
 64:   */
 65:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,"matrix.dat",FILE_MODE_READ,&view);
 66:   MatCreate(PETSC_COMM_WORLD,&A);
 67:   MatSetType(A,MATMPIDENSE);
 68:   MatLoad(A,view);
 69:   PetscViewerDestroy(&view);
 70:   MatView(A,PETSC_VIEWER_STDOUT_WORLD);


 73:   PetscMalloc1((rend-rstart)*n,&array);
 74:   for (i=0; i<(rend-rstart)*n; i++) array[i] = 1.;
 75:   MatDensePlaceArray(A,array);
 76:   MatView(A,PETSC_VIEWER_STDOUT_WORLD);
 77:   MatDenseResetArray(A);
 78:   PetscFree(array);
 79:   MatView(A,PETSC_VIEWER_STDOUT_WORLD);
 80:   MatDestroy(&A);

 82:   PetscFinalize();
 83:   return ierr;
 84: }