Functions to perform posterior predictive model fitting

A series of functions written in the R language for performing posterior predictive simulation under Brownian motion and Early burst models of trait evolution.一系列基于R语言编写的函数，可用于在性状进化的布朗运动（Brownian motion）模型与早爆发模型（Early burst models）下执行后验预测模拟（posterior predictive simulation）。