DescriptionSimulating systems with evolving relational structures on massively parallel computers require the computational work to be evenly distributed across the processing resources throughout the simulation. Adaptive, unstructured, mesh-based finite element and finite volume tools best exemplify this need. We present EnGPar and its diffusive partition improvement method that accounts for multiple application specified criteria. EnGPar's performance is compared against its predecessor, ParMA. Specifically, partition improvement results are provided on up to 512K processes of the Argonne Leadership Computing Facility's Mira BlueGene/Q system.