ADMM and Bethe-ADMM

Major change:
We implemented ADMM and Bethe-ADMM for MAP inference in MRFs. Code available in graphical_models toolkit.

Relevant papers:
Alternating Directions Dual Decomposition.
André F. T. Martins, Mário A. T. Figueiredo, Pedro M. Q. Aguiar, Noah A. Smith, Eric P. Xing.
arXiv:1212.6550.
http://arxiv.org/abs/1212.6550

Bethe-ADMM for Tree Decomposition based Parallel MAP inference
Q. Fu, H. Wang, and A. Banerjee
Conference on Uncertainty in Artificial Intelligence (UAI), 2013.
http://www-users.cs.umn.edu/~banerjee/papers/13/Bethe_ADMM.pdf

There was a minor unintended change of permissions of all files, which we fixed.