GBM multinomial distribution, how to use predict() to get predicted class?

Question

I am using the multinomial distribution from the gbm package in R. When I use the predict function, I get a series of values:

5.0         


        

Answer 1

predict.gbm(..., type='response') is not implemented for multinomial, or indeed any distribution other than bernoulli or poisson.

So you have to find the most likely class (apply(.., 1, which.max) on the vector output from prediction), as desertnaut wrote:

preds = predict(your_model, n.trees, newdata=...,type='response')

pred_class <- apply(preds, 1, which.max)

Just write a wrapper which accepts type='response' and returns this when it's a multinomial model.