The zipfile contains an extended version of the Fast Downward planning system (http://fast-downward.org). The code for CEGAR can be found in the "src/search/cegar" directory. Please see http://www.fast-downward.org for instructions on how to compile the planner. The following configuration computes a single Cartesian abstraction in at most 1000 seconds and uses incremental search to find abstract solutions in the refinement loop: --search "astar(cegar([original()], max_states=infinity, max_transitions=infinity, max_time=1000, memory_padding=100, h_update=dijkstra_from_unconnected_orphans))" We actively maintain the code at https://github.com/jendrikseipp/scorpion.