用偏微分方程法实现 x-y 平面上的给定的椭圆区域的结构化网格划分.同时在控制函数中设置某些参数，还可以实现网格的整体的移动或局部的吸引。-With partial differential equations method to achieve a given xy plane elliptical region structured mesh. While in the control function to set some parameters, but also allows the movement of the grid as a whole or partial attraction.