SATFC (SAT-based Feasibility Checker) solves radio-spectrum repacking feasibility problems arising in the reverse auction of the FCC's upcoming broadcast incentive auction. It combines a formulation of feasibility checking based on propositional satisfiability with a heuristic pre-solver and a SAT solver tuned for the types of instances observed in auction simulations.

Questions, bug reports and feature suggestions should be directed to Neil Newman - newmanne at cs dot ubc dot ca

SATFC is the product of the ideas and hard work of Auctionomics, notably Alexandre Fréchette, Neil Newman, Paul Cernek, Emily Chenn, Guillaume Saulnier-Comte, Nick Arnosti, and Kevin Leyton-Brown.

Stand-alone, ready-to-go releases of SATFC and SATFCServer can be found on the SATFC GitHub page.

Please consult the manual SATFC-manual. The manual is also packaged with any stand-alone SATFC release.

Rough information about the evolution of SATFC through major releases.

• Switch the default portfolio to a newly configured eight core portfolio

• Improve the memory usage of SATFCServer
• Various bugfixes

• Introduce SATenstein, a local search based solver

• ADJ+2 and ADJ-2 constraints
• Enforce arc consistency as a form of preprocessing
• Expanding neighbourhood UNSAT presolver
• Identify conditionally underconstrained stations
• Improve underconstrained station finding heuristic
• Upgrade to clasp 3.1.3
• Multi-permutation server cache to guard against cache query slowdowns

• New required command line parameter for the server, constraint.folder, that tells the server where all of the data folders are so that it can properly size cache entries
• Upgrade to clasp 3.1.2

• New feature, parallel portfolios, allow SATFC to execute multiple solvers in parallel, returning a result as soon as any solver succeeds. Previous versions of SATFC applied each solver sequentially.
• Enhanced the presolver technique to look beyond a station's immediate neighbours

• Upgrade from clasp version from 2 to 3, along with new better performing configurations.
• The SATFCserver now has a clever clean up procedures to prune away unnecessary entries if the cache becomes too big.
• The cache is now updated on the fly. This means instances solved are immediately accessible to future cache queries (improving performance), and the cache server does not need to be restarted to have access to new data (improving usability).

• New feature, containment cache, that uses previously solved problems to solve new, related problems. Our experiments with this feature show that it provides significant performance increase, not only by taking care of problems that are seen often (e.g. from very similar auction runs), but also improving solving time of new, unseen problems. This cache is implemented as a standalone server, the SATFCserver, to allow multiple SATFC solvers to use the same cache and reduce memory overhead. This server in turn uses redis as its backbone cache data structure.

• First official release of SATFC by the FCC.