compile:

make -j2

run:

./two_opt tsp_file

(-j2 option speeds up compilation on multicore machines)

Chances are you will have to change the NVCC option in the makefile to match
the location of your nvcc binary. You will also probably have to change the
NVCCARCH option to match your version of NVCC. This code will probably not
work on versions prior to 3.0.

The tsp format must be in DIMACs format. You can download instances here:
http://dimacs.rutgers.edu/Challenges/TSP/download.html