1. An information processing system comprising: a processor configured for: defining a simulation space comprising a plurality of fragments and a plurality of processor nodes; determining a weight corresponding to the computational cost for a given pairwise fragment interaction; assigning the weight to the simulation space at a point between the two interacting fragments; performing a spatial partitioning of a volume of the simulation space such that all partitions have substantially the same weight; and assigning a computation of the pairwise fragment interaction to any node that has the positions of both groups of fragments.