评估stm模型

Question

我正在做一个STM模型(主题建模)，我想评估和验证这个模型，但我不确定怎么做。我的代码是：

Corpus.STM <- readCorpus(dtm, type = "slam")

型号选择：

BestM1. <- searchK(Corpus.STM$documents, Corpus.STM$vocab, K=c(10,20, 30, 40, 50, 60), proportion = .4, heldout.seed = 1, prevalence=~ cvJahr+ cvDienstgrad+ cvLand, data=Jahr.Land )
BestM2. <- searchK(Corpus.STM$documents, Corpus.STM$vocab, K=c(85,110), proportion = .4, heldout.seed = 1, prevalence=~ cvJahr+ cvDienstgrad+ cvLand, data=Jahr.Land )
BestM3. <- searchK(Corpus.STM$documents, Corpus.STM$vocab, K=c(20,21,22,23,24,25,26,27,28,29,30), proportion = .4, heldout.seed = 1, prevalence=~ cvJahr+ cvDienstgrad+ cvLand, data=Jahr.Land )

str(BestM1.)
plot.searchK(BestM1.)
plot.STM(BestM2)
plot.searchK(BestM3.)
#27 seems to be a good choice
#Heldout
set.seed(1)
heldout<- make.heldout(Corpus.STM$documents, Corpus.STM$vocab, proportion = .5,seed = 1)
stm.mod1 <- stm(heldout$documents, heldout$vocab, K =27, seed = 1, init.type = "Spectral", max.em.its = 100 )
heldout.evaluation <- eval.heldout(stm.mod1, heldout$missing)
heldout.evaluation
#evaluation heldout
labelTopics(stm.mod1) 
plot.STM(stm.mod1, type="labels", n=5, frexweight = 0.25)
cloud(stm.mod1, topic=5)
plot.STM(stm.mod1, type="summary", labeltype="frex", topics=c(1:5), n=8)

我不确定如何解释"eval.heldout“的输出。另外，我想确保模型不会过大，但我不确定它是如何工作的。