中文说明： 此函数求解特征值问题的瑞利波在弹性、 垂向非均匀半空间中并返回模态相速度。用户也可以选择计算： -位移应力矢量 -偏导数的模态瑞利相速度与尊重 每一层的压缩波速与剪切 -有效的瑞雷波相速度造成的叠加 模态相速度和它们的偏导数，和 -使用这一概念的瑞利波位移场的格林函数 振型叠加。
English Description：
This function solves the eigenvalue problem for Rayleigh waves in an elastic, vertically heterogeneous halfspace and returns the modal phase velocities. The user may also choose to calculate: - displacment-stress vectors, - partial derivatives of the modal Rayleigh phase velocities with respect to the shear and compression wave velocities of each layer, - the effective Rayleigh phase velocities resulting from the superposition of the modal phase velocities and their partial derivatives, and