I have a random forest being trained with n vectors each with m variables. Each variable has a cost based on how much time it takes to compute it (m1 might take 1 unit while m2 might take 100, making it more "expensive").
As far as I understand, random forests can give you the contribution each variable make to the whole forest.
My variables are not independent, so there is some correlation between some of them.
What is the correct way to determine the variable importance of the variables making consideration of their cost?