def lognormcdf ( x , mu , tau ) : x = np . atleast_1d ( x ) return np . array ( [ 0.5 * ( 1 - flib . derf ( - ( np . sqrt ( tau / 2 ) ) * ( np . log ( y ) - mu ) ) ) for y in x ] )
numpy python normal cdf
Log - normal cumulative density function
def lognormcdf(x, mu, tau):
    """Log-normal cumulative density function"""
    x = np.atleast_1d(x)
    return np.array(
        [0.5 * (1 - flib.derf(-(np.sqrt(tau / 2)) * (np.log(y) - mu))) for y in x])