Lessons Learned Developing Performance-Portable QMCPACK

The IDEAS Productivity project, in partnership with the DOE Computing Facilities of the ALCF, OLCF, and NERSC, and the DOE Exascale Computing Project (ECP), organizes the webinar series on Best Practices for HPC Software Developers.

As part of this series, we offer one-hour webinars on topics in scientific software development and high-performance computing, approximately once a month. The May webinar is titled Lessons Learned Developing Performance Portable QMCPACK; and will be presented by Paul Kent (Oak Ridge National Laboratory). The webinar will take place on Wednesday, May 10, 2023, at 1:00 pm ET.


During DOE’s Exascale Computing Project the open source QMCPACK code has been redesigned and reimplemented to run portably and performantly on multiple vendors GPUs as well as CPUs. The QMCPACK code implements Quantum Monte Carlo algorithms to predict the properties of materials with benchmark accuracy. The new implementation has now fully replaced the prior non-portable GPU solution. This webinar will outline some of the design considerations and new algorithms implemented both to run efficiently and to reduce burdens on the developers and maintainers. A key factor has been the adoption of modern development practices, including an extensive test suite. This has accelerated development, improved code quality, and also enabled isolation of problems in the wider HPC software stack, including in compilers and numerical libraries. The webinar will summarize these strategies and other recommendations for HPC application developers and facilities.