  Here we propose a new nonparametric framework for two-sample testing, named
as the OVL-$q$ ($q = 1, 2, \ldots$). This can be regarded as a natural
extension of the Smirnov test, which is equivalent to the OVL-1. We
specifically focus on the OVL-2, implement its fast algorithm, and show its
superiority over other statistical tests in some experiments.
