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我正在疏浚一个未标记的入住模型,并遇到了一些障碍:

1)在首先疏通模型的检测组件之后,我试图用之前为检测组件选择的固定预测因子子集来疏通模型的占用组件,如下所示:

global_occ <-occu( ~ Freq + I(Freq^2) + n  +mean_tree_d9 + mean_tree_kurt  ~ C1 + C2 + C3 + C4 + S1 + S2 + S3 + S4 + Hour + I(Hour^2) + Deg_class + Freq_fire + age + Freq + mean_tree_d9 + mean_tree_d4 + mean_tree_d2 + mean_shrub_stdev + mean_tree_kurt + mean_tree_mad, umf_all)

system.time(dredge_occ<-pdredge(global_occ, rank=AIC, m.max=5, cluster=clust, fixed=`p(Freq)`&`p(I(Freq^2))`&`p(n)`&`p(mean_tree_d9)`&`p(mean_tree_kurt)`))


> dredge_occ

Global model call: occu(formula = ~Freq + I(Freq^2) + n + mean_tree_d9 + mean_tree_kurt ~ 
    C1 + C2 + C3 + C4 + S1 + S2 + S3 + S4 + Hour + I(Hour^2) + 
        Deg_class + Freq_fire + age + Freq + mean_tree_d9 + mean_tree_d4 + 
        mean_tree_d2 + mean_shrub_stdev + mean_tree_kurt + mean_tree_mad, data = umf_all)
---
Model selection table 
   p(Int) psi(Int) p(Frq) p(I(Frq^2)) p(men_tre_d9) p(men_tre_krt)    p(n) df    logLik     AIC delta weight
31  -8.68    -1.93 -8.518      -2.439       -0.2369        -0.2295 0.07039  7 -9664.791 19343.6     0      1
Models ranked by AIC(x) 

更新:我尝试在下面使用 Kamil 的解决方案,但它不起作用,因为“m.max”参数对任何单个模型的最大变量数施加了通用约束(跨 p 和 psi 分量),因此不允许要拟合的任何 psi 协变量...

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1 回答 1

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?dredge说:fixed是“单面formula或给出术语名称的字符向量”。在您的情况下,它是一个表达式(适合作为subset参数)。因此,您的代码应为: pdredge(global_occ, rank=AIC, m.max=5, cluster=clust, fixed=c("p(Freq)", "p(I(Freq^2))", "p(n)", "p(mean_tree_d9)", "p(mean_tree_kurt)"))

于 2018-07-19T14:02:55.253 回答