Parametric analysis is often needed for exploring design options, especially when a global optimization method is not available, or the optimization result is in doubt. Parametric analysis can also be applied to all design variables simultaneously, which forms an exhaustive search that, providing that the search grid is fine enough, will guarantee a global optimum solution. In order to perform complex parametric analyses on multiple parameters with more than a handful of alternative values each, a tool to generate commands for the simulation model to run, and to collect results afterwards will be needed. jEPlus has been developed as such a parametric tool for EnergyPlus.
To see jEPlus in action, check out this video: http://youtu.be/jBA7Q7npNK4