sigma_adaptation.py 文件源码

def _update_ps(self, es):
        if not self.is_initialized:
            self.initialize(es)
        if self._ps_updated_iteration == es.countiter:
            return
        z = es.sm.transform_inverse((es.mean - es.mean_old) / es.sigma_vec.scaling)
        # works unless a re-parametrisation has been done
        # assert Mh.vequals_approximately(z, np.dot(es.B, (1. / es.D) *
        #         np.dot(es.B.T, (es.mean - es.mean_old) / es.sigma_vec)))
        z *= es.sp.weights.mueff**0.5 / es.sigma / es.sp.cmean
        # zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
        if es.opts['CSA_clip_length_value'] is not None:
            vals = es.opts['CSA_clip_length_value']
            min_len = es.N**0.5 + vals[0] * es.N / (es.N + 2)
            max_len = es.N**0.5 + vals[1] * es.N / (es.N + 2)
            act_len = sum(z**2)**0.5
            new_len = Mh.minmax(act_len, min_len, max_len)
            if new_len != act_len:
                z *= new_len / act_len
                # z *= (es.N / sum(z**2))**0.5  # ==> sum(z**2) == es.N
                # z *= es.const.chiN / sum(z**2)**0.5
        self.ps = (1 - self.cs) * self.ps + np.sqrt(self.cs * (2 - self.cs)) * z
        self._ps_updated_iteration = es.countiter