A MATLAB program to simulate the geodesic of a surface by a start point and a start direction.
Put two .m files under the same directory, and run 'run_free.m' with MATLAB.
The function file 'geodesic_free.m' are self-explained, please read through it before running.
'run_free.m' script uses GPU by default, the way to use CPU instead is stated in 'geodesic_free.m'.