中文说明：
在Juan Cardelino发布的FMM(fast marching methos)2维程序基础上改写的3维程序。并改写成适合复杂速度模型，可用于地震旅行时计算。大模型3d算法在matlab下计算速度较慢，根据源码中的注释很容易改写成c程序。
English Description：
Based on the FMM (fast marching methos) 2D program released by Juan cardelino, a 3D program is rewritten. It is adapted to complex velocity model and can be used to calculate seismic travel time. The calculation speed of large model 3D algorithm in MATLAB is slow, and it is easy to be rewritten into C program according to the comments in the source code.