tree 0f14c0b9f529afb1dc0fbbf5a5abdd6024c9e097
parent a0c282adbd268c2ad82551fab31fe1cf8d0c4282
author Sameer Agarwal <sameeragarwal@google.com> 1408306490 -0700
committer Sameer Agarwal <sameeragarwal@google.com> 1408985495 -0700

Add an unweighted graph.

Rename Graph -> WeightedGraph.
Add a new Graph class, which is cheaper to construct and
work with if the weights are not needed.

This cuts down the cost of building the Hessian graph
significantly.

Change-Id: Id0cfc81dd2c0bb5ff8f63a1b55aa133c53c0c869