6 /* This example sends a vector and receives individual elements */
8 int main( int argc, char **argv )
11 double *vecin, *vecout, ivalue;
12 int root, i, n, stride, err = 0;
15 MPI_Init( &argc, &argv );
17 MPI_Comm_size( MPI_COMM_WORLD, &size );
18 MPI_Comm_rank( MPI_COMM_WORLD, &rank );
22 vecin = (double *)malloc( n * stride * size * sizeof(double) );
23 vecout = (double *)malloc( n * sizeof(double) );
25 MPI_Type_vector( n, 1, stride, MPI_DOUBLE, &vec );
26 MPI_Type_commit( &vec );
28 for (i=0; i<n*stride*size; i++) vecin[i] = (double)i;
29 for (root=0; root<size; root++) {
30 for (i=0; i<n; i++) vecout[i] = -1.0;
31 MPI_Scatter( vecin, 1, vec, vecout, n, MPI_DOUBLE, root,
33 ivalue = rank * ((n-1) * stride + 1);
35 if (vecout[i] != ivalue) {
36 printf( "Expected %f but found %f\n",
44 MPI_Allreduce( &i, &err, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD );
46 if (err > 0) printf( "Found %d errors!\n", err );
47 else printf( " No Errors\n" );
49 MPI_Type_free( &vec );