Good software for linear/integer programming I never did any linear/integer programming so I am wondering the following two things


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*What are some efficient free linear programming solvers? 

*What are some efficient commercial linear programming solvers? 


It would be nice to supply a dummy usage example with each proposed answer.
Also what if wish to solve a integer programming problem? What are the answers to the above two questions in this case?
I know that integer LP is a hard problem but there are some relaxing methods that are sometimes employed in order to obtain a solution to an integer programming problem. Are there any software packages implementing this kind of stuff?

I would recommend Sage.
It' an excellent Python-based free alternative to Magma, Maple, Mathematica or Matlab!
Formulating LP problems using it it's also quite simple compared to other tools!
