"""Inverted Halo Mass Function (HMF) from the literature
"""
#-----------------------------------------------------------------------------
# Kenza Arraki, 2014
#-----------------------------------------------------------------------------

from __future__ import division

def brook(x):
    """Brook 2014 CLUES inverted subhalo mass function.

    Keyword arguments:
    x -- array of peak halo masses
    """
    tr = 38.1*1.e10/(x**(1./0.89))
    return tr
