ARL Topologies vs OpenMDAO

ARL Topologies is free, open-source software for topology optimization, published by USArmyResearchLab as a United States government project. It is intended for research and general use, and runs self-hosted from the command line with an XML input file. The program separates design representation, optimization method, and objective function. Representations include two- and three-dimensional element-based density discretization with SIMP interpolation, plus nodal-based density discretization with Heaviside projection and filtering. Inputs can be ASCII ExodusII or GMSH meshes, or rectangular pixel and voxel regions. Available optimizers include optimality criterion, method of moving asymptotes, BFGS through NLopt, and a genetic algorithm. Its implemented objective performs static structural finite element analysis. Density results can be post-processed to STL, while VTK, GMSH, and Matlab are output formats. A shared-library objective function allows extension to other problems. Building requires a C++11 compiler and listed libraries.

OpenMDAO is a free, open-source Python framework for systems analysis and multidisciplinary optimization, available for Linux and self-hosted use. It focuses on gradient-based optimization with analytic derivatives, including design spaces with hundreds or thousands of variables. Models combine components and groups, while drivers run optimization algorithms or design of experiments. Nonlinear and linear solvers can be positioned at different levels of the model hierarchy. Derivative tools include analytic partial derivatives, finite-difference and complex-step approximations, derivative checking, and forward or reverse total derivative calculations. MPI features support parallel subsystems and distributed variables across processes. Parallel computing can also support gradient-free optimization, mixed-integer nonlinear programming and design space exploration. Users can visualize models and optimization progress, and record or read model and solver cases. Dymos for transient modeling and optimal control, and pyCycle for turbine engine cycle analysis, are identified as related libraries. Installation is documented through PyPI or a cloned GitHub repository. The supported OpenMDAO 3.x line requires Python 3.10 or later; its API may change periodically during active development.