3D diffusion model code for Fe-Mg in olivine

This is a simple matlab script to model diffusion of Fe-Mg within a 3D numerical olivine. It uses explicit finite differences methods and the Fe-Mg diffusivity expression of Dohmen and Chakraborty (2007).本脚本为一款简易Matlab脚本，用于模拟三维数值橄榄石内部的铁-镁（Fe-Mg）扩散过程。该脚本采用显式有限差分法，并基于Dohmen与Chakraborty于2007年提出的铁-镁扩散系数表达式开展计算。