Here are some sets of optimization benchmarks in six formats: opb, smt2, wcnf, mod (cplex), mzn (minizinc), and cnf (the cnf benchmarks are satisfiability problems set to a specific value of the objective function):
July_2016 (304 Mb)
Dec_2016 (436 Mb)
Sep_2017 (324 kb) [As of this set, the .mod and .mzn formats are included].
Sep_2017 (34 kb) (much smaller benchmarks; best for initial testing)
March_2018 12 Benchmarks, mixed hardness (889 MB)
Please see the readme file for more details.
Near-Optimal Course Scheduling at the Technion. Interfaces, Volume 47 Issue 6, November-December 2017, pp. 537-554.
Contact: Ofer Strichman (ofers AT ie.technion.ac.il)