I'm not an expert on LP-packages, but in my small experience most LP packages are not that great in areas such as API design, modularity, and other similar non-

I'm not an expert on LP-packages, but in my small experience most LP packages are not that great in areas such as API design, modularity, and other similar non-mathematical areas that are important to programmers. My guess is that they wanted something small, simple, and easy to build into other products. I've heard from some of the or_tools developers that the internal usages are most often for rather simple problems. In such cases, ease of use is quite important. That being said, or_tools is a very competent optimization package. For example see the results in the latest MiniZinc Challenge: http://www.minizinc.org/challenge2014/results2014.html http://www.minizinc.org/challenge2014/results2014.html.