copula.py 文件源码

def _logpdf(self, samples):
        if self.theta == 0:
            vals = np.zeros(samples.shape[0])
        else:
            vals = np.log(-self.theta * np.expm1(-self.theta)
                          * np.exp(-self.theta
                                   * (samples[:, 0] + samples[:, 1]))
                          / (np.expm1(-self.theta)
                             + np.expm1(-self.theta * samples[:, 0])
                             * np.expm1(-self.theta * samples[:, 1])) ** 2)
        return vals