Actual source code: ex4.c


  2: static char help[] = "Demonstrates using ISLocalToGlobalMappings.\n\n";

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

  7: int main(int argc,char **argv)
  8: {
  9:   PetscInt               i,n = 4,indices[] = {0,3,9,12},m = 2,input[] = {0,2};
 10:   PetscInt               output[2],inglobals[13],outlocals[13];
 11:   ISLocalToGlobalMapping mapping;

 13:   PetscInitialize(&argc,&argv,(char*)0,help);

 15:   /*
 16:       Create a local to global mapping. Each processor independently
 17:      creates a mapping
 18:   */
 19:   ISLocalToGlobalMappingCreate(PETSC_COMM_WORLD,1,n,indices,PETSC_COPY_VALUES,&mapping);
 20:   ISLocalToGlobalMappingSetFromOptions(mapping);

 22:   /*
 23:      Map a set of local indices to their global values
 24:   */
 25:   ISLocalToGlobalMappingApply(mapping,m,input,output);
 26:   PetscIntView(m,output,PETSC_VIEWER_STDOUT_WORLD);

 28:   /*
 29:      Map some global indices to local, retaining the ones without a local index by -1
 30:   */
 31:   for (i=0; i<13; i++) inglobals[i] = i;
 32:   ISGlobalToLocalMappingApply(mapping,IS_GTOLM_MASK,13,inglobals,NULL,outlocals);
 33:   PetscIntView(13,outlocals,PETSC_VIEWER_STDOUT_WORLD);

 35:   /*
 36:      Map some global indices to local, dropping the ones without a local index.
 37:   */
 38:   ISGlobalToLocalMappingApply(mapping,IS_GTOLM_DROP,13,inglobals,&m,outlocals);
 39:   PetscIntView(m,outlocals,PETSC_VIEWER_STDOUT_WORLD);

 41:   ISLocalToGlobalMappingView(mapping,PETSC_VIEWER_STDOUT_WORLD);
 42:   /*
 43:      Free the space used by the local to global mapping
 44:   */
 45:   ISLocalToGlobalMappingDestroy(&mapping);

 47:   PetscFinalize();
 48:   return 0;
 49: }

 51: /*TEST

 53:    test:

 55:    test:
 56:       suffix: 2
 57:       args: -islocaltoglobalmapping_type hash

 59: TEST*/