MPTRAC vs SimEvents

MPTRAC is a Lagrangian particle dispersion model for studying atmospheric transport in the free troposphere and stratosphere. It calculates forward and backward air-parcel trajectories from meteorological wind fields, with stochastic diffusion, subgrid wind variation and mixing between parcels. Optional process parameterizations cover convection, sedimentation, decay, gas-phase and aqueous-phase chemistry, and wet and dry deposition. Listed research applications include long-range pollutant transport, volcanic ash dispersion, tracer experiments and atmospheric chemistry.

The browser-based Web Runner can configure, run and visualize simulations, then download results without local installation. It is limited to 10,000 air parcels, 30 days and 10 minutes of model runtime. The model needs meteorological input, normally netCDF files on a regular pressure, longitude and latitude grid. MPTRAC supports hybrid MPI, OpenMP and OpenACC parallelization, and offers visualization interfaces for Gnuplot and ParaView. It is GPL-3.0 software for Linux, self-hosted and web use; listed pricing includes free.

SimEvents is desktop software for modeling message-based communication and other event-driven processes. It uses a discrete-event simulation engine and component library, and can combine event-based models with Simulink time-based models for large hybrid systems. Blocks represent entity creation and destruction, queues, service times, routing, attributes, and event responses. Resource Pool, Resource Acquirer, and Resource Releaser blocks model resource allocation, while repeated simulations can support optimization. Analysis includes latency, throughput, packet loss, queue lengths, delays, and average service times. Users can simulate and debug models, inspect queue contents, visualize entity activity, and build custom visualization tools. Output statistics aggregate measures, and Sequence Viewer displays messages, events, and entities. MATLAB Discrete Event System and Discrete Event Chart blocks allow custom behavior. Listed applications include communication networks, software and hardware architectures, forecasting, capacity planning, and supply chain management. SimEvents requires MATLAB and Simulink, runs on Windows, Mac, and Linux, and has a 30-day trial with paid licensing.