将指标添加到 caret 包的默认 train() 输出

Question

我想将除 RMSE 和 Rsquared 之外的其他指标添加到我使用 caret 包创建的线性模型的输出中。据我了解，下面的代码将输出重复交叉验证的 RMSE 和 Rsquared：

library(caret)
lm_reg1 <- train(log1p(mpg) ~ log1p(hp) + log1p(disp),
                 data = mtcars,
                 trControl = trainControl(method = "repeatedcv",
                                          number = 10,
                                          repeats = 10),
                 method = 'lm')
lm_reg

输出：

Linear Regression 

32 samples
10 predictors

No pre-processing
Resampling: Cross-Validated (10 fold, repeated 10 times) 
Summary of sample sizes: 30, 29, 28, 29, 29, 28, ... 
Resampling results:

  RMSE       Rsquared 
  0.1134972  0.8808378

我知道我可以通过修改 trainControl 中的 summaryFunction 并在 metric 参数中引用它的名称来将输出修改为自定义指标。这是我创建的一个计算对数模型 MAPE 的示例：

mape <- function(actual, predicted){
  mean(abs((actual - predicted)/actual))
}
mapeexpSummary <- function (data,
                            lev = NULL,
                            model = NULL) {
  out <- mape(expm1(data$obs), expm1(data$pred))  
  names(out) <- "MAPEEXP"
  out
}
lm_reg2 <- train(log1p(mpg) ~ log1p(hp) + log1p(disp),
                data = mtcars,
                trControl = trainControl(method = "repeatedcv",
                                         number = 10,
                                         summaryFunction = mapeexpSummary,
                                         repeats = 10),
                metric = 'MAPEEXP',
                method = 'lm')
lm_reg2

输出：

Linear Regression 

32 samples
10 predictors

No pre-processing
Resampling: Cross-Validated (10 fold, repeated 10 times) 
Summary of sample sizes: 28, 29, 29, 28, 28, 30, ... 
Resampling results:

  MAPEEXP  
  0.1022028

有没有办法将它们添加到单个输出中？我希望保存所有这些值，但希望避免为此创建两个相同的模型。

Answer 1

在mapeexpSummary 中添加 RMSE 和 Rsquared？

mapeexpSummary <- function (data,
    lev = NULL,
    model = NULL) {
    c(MAPEEXP=mape(expm1(data$obs), expm1(data$pred)),
        RMSE=sqrt(mean((data$obs-data$pred)^2)),
        Rsquared=summary(lm(pred ~ obs, data))$r.squared)
}