Actual source code: ex11.c


  2: static char help[]= "Scatters between parallel vectors. \n\
  3: uses block index sets\n\n";

  5: #include <petscvec.h>

  7: int main(int argc,char **argv)
  8: {
 10:   PetscInt       bs=1,n=5,N,i,low;
 11:   PetscInt       ix0[3] = {5,7,9},iy0[3] = {1,2,4},ix1[3] = {2,3,1},iy1[3] = {0,3,9};
 12:   PetscMPIInt    size,rank;
 13:   PetscScalar    *array;
 14:   Vec            x,x1,y;
 15:   IS             isx,isy;
 16:   VecScatter     ctx;
 17:   VecScatterType type;
 18:   PetscBool      flg;

 20:   PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
 21:   MPI_Comm_size(PETSC_COMM_WORLD,&size);
 22:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);

 24:   if (size <2) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_WRONG_MPI_SIZE,"Must run more than one processor");

 26:   PetscOptionsGetInt(NULL,NULL,"-bs",&bs,NULL);
 27:   n    = bs*n;

 29:   /* Create vector x over shared memory */
 30:   VecCreate(PETSC_COMM_WORLD,&x);
 31:   VecSetSizes(x,n,PETSC_DECIDE);
 32:   VecSetFromOptions(x);

 34:   VecGetOwnershipRange(x,&low,NULL);
 35:   VecGetArray(x,&array);
 36:   for (i=0; i<n; i++) {
 37:     array[i] = (PetscScalar)(i + low);
 38:   }
 39:   VecRestoreArray(x,&array);
 40:   /* VecView(x,PETSC_VIEWER_STDOUT_WORLD); */

 42:   /* Test some vector functions */
 43:   VecAssemblyBegin(x);
 44:   VecAssemblyEnd(x);

 46:   VecGetSize(x,&N);
 47:   VecGetLocalSize(x,&n);

 49:   VecDuplicate(x,&x1);
 50:   VecCopy(x,x1);
 51:   VecEqual(x,x1,&flg);
 52:   if (!flg) SETERRQ(PetscObjectComm((PetscObject)x),PETSC_ERR_ARG_WRONG,"x1 != x");

 54:   VecScale(x1,2.0);
 55:   VecSet(x1,10.0);
 56:   /* VecView(x1,PETSC_VIEWER_STDOUT_WORLD); */

 58:   /* Create vector y over shared memory */
 59:   VecCreate(PETSC_COMM_WORLD,&y);
 60:   VecSetSizes(y,n,PETSC_DECIDE);
 61:   VecSetFromOptions(y);
 62:   VecGetArray(y,&array);
 63:   for (i=0; i<n; i++) {
 64:     array[i] = -(PetscScalar) (i + 100*rank);
 65:   }
 66:   VecRestoreArray(y,&array);
 67:   VecAssemblyBegin(y);
 68:   VecAssemblyEnd(y);
 69:   /* VecView(y,PETSC_VIEWER_STDOUT_WORLD); */

 71:   /* Create two index sets */
 72:   if (rank == 0) {
 73:     ISCreateBlock(PETSC_COMM_SELF,bs,3,ix0,PETSC_COPY_VALUES,&isx);
 74:     ISCreateBlock(PETSC_COMM_SELF,bs,3,iy0,PETSC_COPY_VALUES,&isy);
 75:   } else {
 76:     ISCreateBlock(PETSC_COMM_SELF,bs,3,ix1,PETSC_COPY_VALUES,&isx);
 77:     ISCreateBlock(PETSC_COMM_SELF,bs,3,iy1,PETSC_COPY_VALUES,&isy);
 78:   }

 80:   if (rank == 10) {
 81:     PetscPrintf(PETSC_COMM_SELF,"\n[%d] isx:\n",rank);
 82:     ISView(isx,PETSC_VIEWER_STDOUT_SELF);
 83:     PetscPrintf(PETSC_COMM_SELF,"\n[%d] isy:\n",rank);
 84:     ISView(isy,PETSC_VIEWER_STDOUT_SELF);
 85:   }

 87:   /* Create Vector scatter */
 88:   VecScatterCreate(x,isx,y,isy,&ctx);
 89:   VecScatterSetFromOptions(ctx);
 90:   VecScatterGetType(ctx,&type);
 91:   PetscPrintf(PETSC_COMM_WORLD,"scatter type %s\n",type);

 93:   /* Test forward vecscatter */
 94:   VecSet(y,0.0);
 95:   VecScatterBegin(ctx,x,y,ADD_VALUES,SCATTER_FORWARD);
 96:   VecScatterEnd(ctx,x,y,ADD_VALUES,SCATTER_FORWARD);
 97:   PetscPrintf(PETSC_COMM_WORLD,"\nSCATTER_FORWARD y:\n");
 98:   VecView(y,PETSC_VIEWER_STDOUT_WORLD);

100:   /* Test reverse vecscatter */
101:   VecSet(x,0.0);
102:   VecSet(y,0.0);
103:   VecGetOwnershipRange(y,&low,NULL);
104:   VecGetArray(y,&array);
105:   for (i=0; i<n; i++) {
106:     array[i] = (PetscScalar)(i+ low);
107:   }
108:   VecRestoreArray(y,&array);
109:   VecScatterBegin(ctx,y,x,ADD_VALUES,SCATTER_REVERSE);
110:   VecScatterEnd(ctx,y,x,ADD_VALUES,SCATTER_REVERSE);
111:   PetscPrintf(PETSC_COMM_WORLD,"\nSCATTER_REVERSE x:\n");
112:   VecView(x,PETSC_VIEWER_STDOUT_WORLD);

114:   /* Free objects */
115:   VecScatterDestroy(&ctx);
116:   ISDestroy(&isx);
117:   ISDestroy(&isy);
118:   VecDestroy(&x);
119:   VecDestroy(&x1);
120:   VecDestroy(&y);
121:   PetscFinalize();
122:   return ierr;
123: }

125: /*TEST

127:    test:
128:       nsize: 2

130: TEST*/