I have a few categorical variables which are set as factors in R, so they are internally represented as distinct integers.
Say in the case of a categorical variable with 3 levels, can I just leave it alone and SVM handles this automatically: levels 1, 2, 3. Or do I have to dummy code them to two columns like so:
x0 x1 0 0 = level 1 0 1 = level 2 1 0 = level 3
I looked in the documentation where it sounds like if you use the formula interface (which I do), then this is handled automatically:
"If the predictor variables include factors, the formula interface must be used to get a correct model matrix."
Does this mean so long as I use the formula interface "dummy coding" is happening for me behind the scenes?