I'm using gbm package to create a gradient boosting model with multinomial family. I have problems in plotting and interpreting partial dependence plots with this type of models.
an example:
library(gbm)
data(iris)
GBM.model = gbm(Species ~ Sepal.Length + Sepal.Width + Petal.Length + Petal.Width, data = iris,distribution = "multinomial")
plot.gbm(GBM.model, "Petal.Length")
Could you help me to improve the plot and interpret it? I think it should have a line for each category of the response variable but I'm not sure. Is there another way of getting partial dependence plots for multinomial gbm models? I would appreciate any help with this