OpenMM

OpenMM is an open-source molecular dynamics toolkit designed to enable fast, flexible simulations of biomolecular systems on CPUs and GPUs. It provides a high-performance C++ core with Python and C++ APIs, and is intended to be easily extensible for researchers who want to prototype new models or scale simulations.

The toolkit emphasizes portability and performance, supporting execution on CPUs, NVIDIA CUDA GPUs, and other accelerators through a platform abstraction. Users can create simulation systems by defining forces, integrators, and environments. OpenMM includes common integrators (for example, Langevin and Verlet-style schemes), thermostats and barostats, and support for constraints. It also provides support for standard force fields via a ForceField mechanism and enables user-defined potentials through "Custom Forces" and a "Custom Integrator" for bespoke simulation workflows. Long-range electrostatics and nonbonded interactions are supported with efficient algorithms.

OpenMM emphasizes interoperability and workflow integration. It can read and interpret common molecular structures and parameters, and it interoperates with other cheminformatics tools and data formats through wrappers and auxiliary libraries, enabling workflows that combine structure preparation, parameterization, and analysis.

The ecosystem includes OpenMMTools, a collection of advanced sampling methods and utilities built on top of OpenMM, and various community contributions that extend functionality. OpenMM is widely used in biomolecular simulation, free-energy calculations, and method development, benefiting from an active user and developer community.