The SAT 2005 Solver Competition on Random Instances

An analysis of the SAT 2005 sub-competition on random instances is given. This year this (sub-)competition set-up was geared to establish a basic setting, focusing on the instances near the (infamous) “50% densities”, so first we have to establish a more quantitative understanding of phase transitions here. We present extended empirical results, clearly showing that the models used before, which are motivated by large-scale considerations, are inadequate at the relatively small scale considered here. Then the series’ and all individual instances used in the competition are described. We give a formal definition of the competition evaluation, and analyse the results of the competition, looking into the details of the scoring mechanism as well as into alternative evaluation methods.