chx_speckle.py 文件源码

def gammaDist(x,params):
    '''Gamma distribution function
    M,K = params, where K is  average photon counts <x>,
    M is the number of coherent modes,
    In case of high intensity, the beam behavors like wave and
    the probability density of photon, P(x), satify this gamma function.
    '''

    K,M = params
    K = float(K)
    M = float(M)
    coeff = np.exp(M*np.log(M) + (M-1)*np.log(x) - gammaln(M) - M*np.log(K))
    Gd = coeff*np.exp(-M*x/K)
    return Gd