遗传算法迭代速度时快时慢

遗传算法运行同一个程序运行速度有时特别快，一两分钟就可以迭代1500次，有时候需要十几分钟甚至20多分钟，我没有设置任何加速，无法复现速度特别快的时候，只能靠运气。应该不是电脑的原因，cpu的使用率一直在20%。

The issue names no file, test, or reproducible program. Start by comparing repeated runs of the same genetic-algorithm program while recording iteration timing and CPU usage; done means identifying a reproducible cause for the runtime variation or documenting why it varies.

Written by the indexing model from the issue text.