import math


def getCSLi(ic_1,ic_2,ic_lca):
    """
    CS calculation based on Li et al. https://doi.org/10.1109/TKDE.2003.1209005
    """
    return math.exp(0.2*(ic_1 + ic_2 - 2*ic_lca))*(math.exp(0.6*ic_lca)-math.exp(-0.6*ic_lca))/(math.exp(0.6*ic_lca)+math.exp(-0.6*ic_lca))