Runtime and growth-behavior comparison of vEcoli — the established vivarium-based E. coli whole-cell model — and v2ecoli, the current process-bigraph baseline. Each engine runs from its own ParCa-generated sim_data (vEcoli's regenerated from current master; v2ecoli's from its own cache) over the same simulated duration, so the comparison reflects engine and runtime differences rather than a re-parameterization of the biology.
