Off by one?

I'm wondering why this code has (feature_id - 1):

https://github.com/atomashpolskiy/rustface/blob/807ae56ff6e818d90908835d45db15cc12f12d8d/src/classifier/surf_mlp_classifier.rs#L212-L216

shouldn't it advance the pointer by the size of the same feature vector that has been copied, not the next one?

Start at src/classifier/surf_mlp_classifier.rs lines 212-216 and trace how feature_id and the feature-vector pointer are calculated. Compare the pointer advance with the size of the copied vector and inspect nearby classifier code for the intended indexing. Done means resolving whether the -1 is erroneous and correcting it if confirmed.

Written by the indexing model from the issue text.