有限差分法求解拉普拉斯方程,超松弛迭代，光波波长计算模拟-Finite difference method for solving the Laplace equation, SOR, the wavelength computational simulation

位场向下延拓的泰勒级数方法，利用拉普拉斯方程的特点，计算空间域水平二阶差分来替代垂直方向上的二阶差分-Potential field downward continuation of Taylor series method, the advantage of the characteristics of Laplace equation, a second order differential spatial domain levels instead of second order diff