Overview

Phase diagram of the Cu-Zr system predicted by exa-PD using an EAM-FS potential

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Exa-PD is a highly parallelizable workflow for constructing multi-element phase diagrams (PDs). It uses standard sampling techniques—molecular dynamics (MD) and Monte Carlo (MC)—as implemented in the LAMMPS package, to simultaneously sample multiple phases on a fine temperature–composition mesh for free-energy calculations. The workflow uses Parsl as a global controller to manage the MD/MC jobs to achieve massive parallelization with almost ideal scalability. The resulting free energies of both liquid and solid phases (including solid solutions) are then fed to CALPHAD modeling using the PYCALPHAD package for the construction of a multi-element PD.

Contents:

• Quickstart
  • Prerequisites
  • Installation
  • Using a JSON Configuration File
• Tutorial
  • 1. Clone the Repository
  • 2. Install Dependencies
  • 3. Prepare the Data and LAMMPS Setup
  • 3. Prepare the Parsl Configuration
  • 5. Prepare the JSON Input File
  • 6. Run the Workflow
• API Reference for exaPD
  • Core LAMMPS Job Infrastructure
  • Thermodynamic Integration & Free Energy
  • Hybrid Monte Carlo and Molecular Dynamics
  • Solid Liquid Coexistence