保存/加载 M5 RWeka 插入符号模型失败 [英] Save/load a M5 RWeka caret model fails

问题描述

我在通过 Caret 加载 RWeka 包的已保存 M5 实现后出现错误.

I'm coming up with an error after loading a saved M5 implementation of the RWeka package via Caret.

.jcall(o, "Ljava/lang/Class;", "getClass") 中的错误:

Error in .jcall(o, "Ljava/lang/Class;", "getClass") :

RcallMethod:尝试调用一个 NULL 对象的方法.

RcallMethod: attempt to call a method of a NULL object.

重现错误:

library(caret); library(RWeka)
data(GermanCredit)

myModel <- train(Duration~Amount, data=GermanCredit, method="M5")
predict(myModel, GermanCredit[1,]) # Works.

save(myModel, file="myModel.rda")
load("myModel.rda")
predict(myModel, GermanCredit[1,]) # Produces the RcallMethod error.

这篇文章 表示 RWeka 对象是对 Java 对象的引用，该对象必须被序列化才能正确保存/加载.

This post indicates that RWeka objects are references to a Java object, and that object must be serialized in order to save/load properly.

但是，我找不到将其扩展到 Caret 包实现的正确命令.

However, I cannot find the right commands to extend this to the Caret package implementation.

推荐答案

http://one-line-it.blogspot.tw/2013/03/r-store-rweka-model-to-file.html

library(RWeka)
j48.model <- J48(formula=class ~ ., data=data)
library(rJava)
.jcache(j48.model$classifier)
save(j48.model, file="j48.model.rda")

这可能对您有所帮助.

顺便说一句有没有可以将 J48 Rweka 分类器变成规则的方法?

btw Are there methods that can make a J48 Rweka classifier into rules?

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