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

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


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

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

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

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

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

 48:   VecDuplicate(x,&x1);
 49:   VecCopy(x,x1);
 50:   VecEqual(x,x1,&flg);

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

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

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

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

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

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

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

113:   /* Free objects */
114:   VecScatterDestroy(&ctx);
115:   ISDestroy(&isx);
116:   ISDestroy(&isy);
117:   VecDestroy(&x);
118:   VecDestroy(&x1);
119:   VecDestroy(&y);
120:   PetscFinalize();
121:   return 0;
122: }

124: /*TEST

126:    test:
127:       nsize: 2

129: TEST*/