WESTPA 2.0: High-Performance Upgrades for Weighted Ensemble Simulations and Analysis of Longer-Timescale Applications

John D. Russo, She Zhang, Jeremy M.G. Leung, Anthony T. Bogetti, Jeff P. Thompson, Alex J. Degrave, Paul A. Torrillo, A. J. Pratt, Kim F. Wong, Junchao Xia, Jeremy Copperman, Joshua L. Adelman, Matthew C. Zwier, David N. Lebard, Daniel M. Zuckerman, Lillian T. Chong

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


The weighted ensemble (WE) family of methods is one of several statistical mechanics-based path sampling strategies that can provide estimates of key observables (rate constants and pathways) using a fraction of the time required by direct simulation methods such as molecular dynamics or discrete-state stochastic algorithms. WE methods oversee numerous parallel trajectories using intermittent overhead operations at fixed time intervals, enabling facile interoperability with any dynamics engine. Here, we report on the major upgrades to the WESTPA software package, an open-source, high-performance framework that implements both basic and recently developed WE methods. These upgrades offer substantial improvements over traditional WE methods. The key features of the new WESTPA 2.0 software enhance the efficiency and ease of use: an adaptive binning scheme for more efficient surmounting of large free energy barriers, streamlined handling of large simulation data sets, exponentially improved analysis of kinetics, and developer-friendly tools for creating new WE methods, including a Python API and resampler module for implementing both binned and "binless"WE strategies.

Original languageEnglish (US)
Pages (from-to)638-649
Number of pages12
JournalJournal of Chemical Theory and Computation
Issue number2
StatePublished - Feb 8 2022

ASJC Scopus subject areas

  • Computer Science Applications
  • Physical and Theoretical Chemistry


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