Modularity models for P-matrices without allometry

Description of modularity models used to test P-matrices without allometric size variation. May be used as argument 'mod' in 'EMMLi' R function.用于在无异速生长尺寸变异（allometric size variation）条件下检验P矩阵（P-matrices）的模块化模型（modularity models）的说明文档。此类模型可作为参数'mod'在'EMMLi' R函数中使用。