What is WESTPA?

WESTPA (The Weighted Ensemble Simulation Toolkit with Parallelization and Analysis) is a high-performance framework for carrying out extended-timescale simulations of rare events with rigorous kinetics using the weighted ensemble algorithm of Huber and Kim (1996) (an overview is provided here). The software also includes (1) options for further enhancing the sampling efficiency through reassignment of weights according to either equilibrium or nonequilibrium steady state , and (2) a plugin for using a weighted ensemble-based string method.

Key features of the software:

  • Highly scalable. Nearly perfect scaling up to thousands of cores.
  • Interoperable. Designed to conveniently interface with any stochastic sampling engine (e.g., molecular dynamics, Brownian dynamics, and Monte Carlo engines).
  • Portable. The software can be used with any Unix operating system (e.g. Linux or OS X), including typical clusters and supercomputers.
  • Free and open source. All source code is available under the GNU GPL license.

Please cite the following for use of WESTPA:

MC Zwier, JL Adelman, JW Kaus, AJ Pratt, KF Wong, NB Rego, E Suárez, S Lettieri, DW Wang, M Grabe, DM Zuckerman, and LT Chong. “WESTPA: An interoperable, highly scalable software package for weighted ensemble simulation and analysis”. J. Chem. Theory Comput., 11: 800-809 (2015).

Getting Help

Documentation and tutorials for WESTPA can be found here. For additional support, you can search the archives of the WESTPA users mailing list.

We strongly suggest that you subscribe to the low-volume email list and use the most recent version of WESTPA before posting issues to this list.

Finally, while WESTPA is a powerful tool that enables expert simulators to access much longer timescales than is practical with standard simulations, there can be a steep learning curve to figuring out how to effectively run the simulations on your computing resource of choice. For serious users who have completed the online tutorials and are ready for production simulations of their system, we invite you to contact Lillian Chong (ltchong AT pitt DOT edu) about spending a few days with her lab and/or setting up video conferencing sessions to help you get your simulations off the ground.

To help us improve WESTPA please fill out a one-minute survey and consider contributing documentation or code to the WESTPA community.


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