5个f语言有限差分正演程序，应用有限差分法在CPML边界条件下进行2D正演，前四个程序分别对应各向异性介质、各项同性2阶精度、各项同性4阶精度、双相介质4阶精度四种不同情况。最后一个是3D粘弹性介质的程序。-5 f language finite difference modeling, application of finite difference method under CPML boundary conditions 2D forward, the first four programs corresponding to anisotropic media, the isotropic second order accuracy, isotropic 4th order accuracy, double phases 4 order accuracy in four different situations. The last one is the program 3D viscoelastic medium.