求助gmx select中olt选项和residential autocorrelation functions类似吗？

MGRACE

请教下各位老师，想要计算原子附近水分子的residential autocorrelation functions，概念如图（https://doi.org/10.1016/j.memsci.2022.120498）。查阅gmx手册发现gmx_select中的olt选项输出的lifetime.xvg有如此说明：With -olt, a histogram is produced that shows the number ofselected positions as a function of the time the position wascontinuously selected.
现在有两个疑问，olt选项的原理公式是什么？二者的计算结果是否类似呢？