Also , general relativity defines non - inertia space - time as a space of riemann . for riemann space has positive curvature , we have to doubt about where the minus curvature space is 广义相对论把非惯性时空定义为黎曼空间,但由于黎曼几何是正曲率空间,既然广义时空是对称的,我们必然要问,负曲率空间到哪去了?
Firstly the stochastic gradient algorithm based on minimum mutual information ( mmi ) is researched , and this algorithm is simple and stable , but its convergence speed is slow . secondly the natural gradient algorithm based on riemann space is researched . finally easi algorithm , iterative inversion algorithm and some 首先研究了基于最小化互信息的随机梯度算法,该算法简单稳定但收敛较慢,然后研究了基于黎曼空间的自然梯度算法,最后介绍了easi算法、迭代求逆算法以及其余一些算法。