ML Communities

Cross Validated

Useful tools

dLib: A great C++ library with Python API.
Gurobi: A good solver for optimization problems, compatible with cvx and has free academic license.
VLFeat: A library that implements popular computer vision algorithms specializing in image understanding, feature extraction and matching.
libSVM: A library that implements Support Vector Machines.

Datasets

SNAP: A collection of large network/graph datasets.

Group resources

ML sessions