def points_in_ring(distance_vector, inner_radius, outer_radius):
    """
    Returns the indices of all points within a given distance from
    a distance vector. The vector is assumed to be 1d.

    Parameters
    ----------
    distance_vector : ndarray
                      (n,1) array of distances between a point and a set of points
    inner_radius : float
                   The lower threshold for the ring
    outer_radius : float
                   The outer threshold for the ring

    Returns
    -------
     : ndarray
       (n,1) array of booleans where all correspondences inside of the array are True
    """
    return (distance_vector >= inner_radius) * (distance_vector <= outer_radius)