void LAX_ddot_strided_blas(LA_Dvector_ddot_stride_binop *xy)
{
  int    start, stride;
  double local_sum = 0.0, sum;
  LA_Dvector *x, *y;
  
  /* Dereference the binary vector operands: */
  x = xy -> binop.x;  y = xy -> binop.y;

  /* Determine the stride based on type */
  start  = xy -> local_start; 
  stride = xy -> local_stride;
  
  /* Sum up my part */
  blas_ddot(&(x->v->m), &(x->v->data[start]), &stride,
	    &(y->v->data[start]), &stride);

  /* Get the sum of all parts, put result back in object */
  MPI_Allreduce(&local_sum, &(xy->result[0]), 1, MPI_DOUBLE, MPI_SUM,
                xy->binop.comm);
  /* Return result */
  xy -> binop.error = 0;
}