Explaining the poor performance of the KASS algorithm implementation

Abstract

By investigating the code for the KASS algorithm implementation used in the paper "Exploring the quantum speed limit with computer games" [1, arXiv:1506.09091] by Sørensen et al. (provided by the authors), we describe how the poor performance of the KASS algorithm reported in [1] is entirely caused by a simple sign error in a derivative calculation. Changing only this one sign in the KASS implementation, we show that the algorithm provides results comparable to all other algorithms considered for the problem [2,7], and performs better than all player solutions of [1]. Furthermore, we show that the player solutions were optimized with a different algorithm before being compared to the results from the KASS algorithm. The authors of [1] have acknowledged both findings. Finally, we show that in contrast to the claims in [1], the players did not explore two different strategies. In fact, all the players followed the same strategy.