1
http://web.mit.edu/lpsolve/doc/mps-format.htm
2
http://web.mit.edu/lpsolve/doc/CPLEX-format.htm
3
Adapted from
https://www.gnu.org/software/gsl/doc/html/siman.html\#trivial-example
4
Adapted from
https://www.gnu.org/software/gsl/doc/html/siman.html\#traveling-salesman-problem