Actual source code: ex2.c

  1: /*$Id: ex2.c,v 1.54 2001/08/07 03:02:26 balay Exp $*/

  3: static char help[] = "Tests vector scatter-gather operations.  Input arguments aren
  4:   -n <length> : vector lengthnn";

 6:  #include petscvec.h
 7:  #include petscsys.h

  9: int main(int argc,char **argv)
 10: {
 11:   int           n = 5,ierr,idx1[2] = {0,3},idx2[2] = {1,4};
 12:   PetscScalar   one = 1.0,two = 2.0;
 13:   Vec           x,y;
 14:   IS            is1,is2;
 15:   VecScatter    ctx = 0;

 17:   PetscInitialize(&argc,&argv,(char*)0,help);
 18:   PetscOptionsGetInt(PETSC_NULL,"-n",&n,PETSC_NULL);

 20:   /* create two vector */
 21:   VecCreateSeq(PETSC_COMM_SELF,n,&x);
 22:   VecDuplicate(x,&y);

 24:   /* create two index sets */
 25:   ISCreateGeneral(PETSC_COMM_SELF,2,idx1,&is1);
 26:   ISCreateGeneral(PETSC_COMM_SELF,2,idx2,&is2);

 28:   VecSet(&one,x);
 29:   VecSet(&two,y);
 30:   VecScatterCreate(x,is1,y,is2,&ctx);
 31:   VecScatterBegin(x,y,INSERT_VALUES,SCATTER_FORWARD,ctx);
 32:   VecScatterEnd(x,y,INSERT_VALUES,SCATTER_FORWARD,ctx);
 33: 
 34:   VecView(y,PETSC_VIEWER_STDOUT_SELF);

 36:   VecScatterBegin(y,x,INSERT_VALUES,SCATTER_FORWARD,ctx);
 37:   VecScatterEnd(y,x,INSERT_VALUES,SCATTER_FORWARD,ctx);
 38:   VecScatterDestroy(ctx);

 40:   PetscPrintf(PETSC_COMM_SELF,"-------n");
 41:   VecView(x,PETSC_VIEWER_STDOUT_SELF);

 43:   ISDestroy(is1);
 44:   ISDestroy(is2);

 46:   VecDestroy(x);
 47:   VecDestroy(y);

 49:   PetscFinalize();
 50:   return 0;
 51: }
 52: