绘制庞加莱截面图的程序。先通过solveLor.m来求出一系列点，然后代入Poincare_section 程序绘制庞加莱截面。

通过观察Poincare截面上截点的情况可以判断

是否发生混沌：当Poincare截面上有且只有一个不动点或少数离散点时，运动是周期的；当Poincare截面上是一封闭曲线时，运动是准周期的 当Poincare截面上是一些成片的具有分形结构的密集点时，运动便是混沌。 -Poincare section drawing program. First obtained by solveLor.m to a series of points, and then drawn into the program Poincare Poincare section. By observing the situation on the Poincare section cut points can determine whether chaos occurs: When there is only one fixed point or a few discrete points on the Poincare section, the motion is periodic　When is a closed curve on the Poincare section, the motion is quasi- When is the point of having a dense fractal structure on some stretches of the Poincare section, the motion is chaotic　period.