kroupa.py 文件源码

def prior_cdf(self, u):
        """Inverse cumulative density function from Kroupa 2001b.

        output mass scaled to 0-1 interval
        min mass before scaling = 0.01
        """
        self._norm = 1. / self.kroupa_cdf(self._max_value, 1)
        if u < self.kroupa_cdf(0.08, self._norm):
            value = (u * (0.7) / self._norm * 0.08**(-0.3) +
                     0.01**0.7)**(1 / 0.7)
        elif u < self.kroupa_cdf(0.5, self._norm):
            value = (((u - (self._norm / 0.7 * 0.08**0.3 *
                            (0.08**0.7 - 0.01**0.7))) * (-0.3) / self._norm *
                      0.08**(-1.3) + 0.08**(-0.3))**(1 / -0.3))
        else:
            value = (((u - (self._norm / -0.3) * 0.08**1.3 *
                       (0.5**(-0.3) - 0.08**(-0.3)) -
                       (self._norm / 0.7 * 0.08**0.3 *
                        (0.08**0.7 - 0.01**0.7))) * -1.3 / self._norm *
                      0.5**(-2.3) * (6.25)**1.3 + 0.5**(-1.3))**(1 / -1.3))

        value = (value - self._min_value) / (self._max_value - self._min_value)
        # np.clip in case of python errors in line above
        return np.clip(value, 0.0, 1.0)