I wrote the solver code used here as an example for the JuMP modeling package for Julia, which is available at https://github.com/JuliaOpt/JuMP.jl. The specific TSP example code is available at https://github.com/JuliaOpt/JuMP.jl/blob/master/examples/tsp..., and more general information about optimization in Julia is available at http://juliaopt.org