Error predict with mlr:

Question

I tried to train a h2o model using the following code and make a prediction for new data, but it leads to an error. How can I avoid this error?

library(mlr)
a <- data.frame(y=factor(c(1,1,1,1,1,1,1,1,0,0,1,0)), 
                x1=rep(c("a","b","c"), times=c(6,3,3)))
aTask <- makeClassifTask(data = a, target = "y", positive = "1")
h2oLearner <- makeLearner("classif.h2o.deeplearning", 
                          predict.type = "prob")
model <- train(h2oLearner, aTask)

b <- data.frame(x1=rep(c("a","b", "c"), times=c(3,5,4)))
pred <- predict(model, newdata=b)

leads to the following error:

Error in checkPredictLearnerOutput(.learner, .model, p) :
predictLearner for classif.h2o.deeplearning has returned not the class levels as column names: p0,p1

If I change predict.type to "response" it works. So how to predict probabilities?

Answer 1

This bug was fixed in this commit and will be in the next release. Until then, you can install the Github version:

devtools::install_github("mlr-org/mlr")