utils.py 文件源码

def hp_kd_tree(nside=set_default_nside(), leafsize=100):
    """
    Generate a KD-tree of healpixel locations

    Parameters
    ----------
    nside : int
        A valid healpix nside
    leafsize : int (100)
        Leafsize of the kdtree

    Returns
    -------
    tree : scipy kdtree
    """
    hpid = np.arange(hp.nside2npix(nside))
    ra, dec = _hpid2RaDec(nside, hpid)
    x, y, z = treexyz(ra, dec)
    tree = kdtree(list(zip(x, y, z)), leafsize=leafsize, balanced_tree=False, compact_nodes=False)
    return tree