I am looking for a complete CSP solver, meaning it will always find a solution if it exists and will tell you if no solution exists. A solver that is optimized for graph coloring is preferred, but not necessary. There are many iterative algorithms/solvers out there but I require a completeness(?) for my work.
I have implemented my own solver using the Weak-Commitment Search algorithm but I'm sure there are many optimizations and thread-based features that could make for a much faster solver and allow me to increase the number of variables I can use in my simulation. I realize it's an exponentially difficult problem, but every little bit will help!