EFD如何判别计算收敛？

从EFD的帮助文档中找到如下语句。依然无法明白其计算收敛的判别方法。
When EFD.Lab analyzes the goal's convergence, it
calculates the goal's dispersion defined as the difference between the goal's
maximum and minimum values over the analysis interval reckoned from the last
iteration and compares this dispersion with the goal's convergence criterion
dispersion, either specified by you or automatically determined by EFD.Lab as a
fraction of the goal's physical parameter dispersion over the analysis interval
reckoned from the fourth iteration until one travel is completed.

这个还真看不懂！！！！！