At my current job we use Optaplanner in a project, to move around seat reservations (in blocks of several hundred) whilst keeping the new seats as similar as possible to the old ones (each seat having 'attributes' with various weights). I mostly chose it due to being JVM (although it needed a little Java shim to make it usable from Scala)
In grad school I used MiniZinc to find exact optimal subsets for a certain problem, which took AGES and was only practical up to sets of size 11, but I could use its output as a benchmark for my own approximate solver.
In grad school I used MiniZinc to find exact optimal subsets for a certain problem, which took AGES and was only practical up to sets of size 11, but I could use its output as a benchmark for my own approximate solver.