Currently new features can't be used with Feature Extractor and probably some steps additional to 'How to : add feature' needs to be taken. Extractor gives feature is not registered error when .Add() called with feature extractor engine. I think solution to this is using RegisterClass in feature/feature_extractor.cc. After registering the feature, .Add() works and .GetList() includes the new feature, but it gives segmentation fault during .Extract().

I have added a copy of degrees feature with different name and feature extractor does not work with it as well.

Another possibly necessary change probably is adding GetFeatureX(), GetFeatureXCached() in bases/graph_feature_base.h. Extractor still gives segmentation fault after this change.

Additional changes needed to be determined, then should be applied on new features, and finally added to the documentation under "How to: add a new feature". Also it might be a good idea to add seperate tests for each feature that uses feature extractor engine, testing engine.Add() and Extract() with that feature.