中文说明：该函数用来计算任意函数的一阶偏导数(数值方法),采用的是通用的平面波展开法,这个有中文注释，看得明白，能量熵的计算，包括面积、周长、矩形度、伸长度，具有丰富的参数选项。
English Description：
This function is used to calculate the first order partial derivatives of a function (method), using the plane wave expansion method is common, the Chinese comments, understand it, energy calculation of entropy, including area, perimeter, rectangular, elongation, has a wealth of options.