February 2024 OLCF User Conference Call: Gordon Bell User Experience Talk
The OLCF hosts monthly User Conference Calls. These calls are your opportunity to speak with center personnel to get the latest updates, express any concerns you may have, etc. No registration is required for this event.
Monthly Topic: Large-scale DFT simulations commensurate with quantum accuracy: our experience on the exascale Frontier machine
Speaker: Sambit Das (U. Mich.); Bikash Kanungo (U. Mich.); David Rogers (ORNL)
Abstract: Ab initio electronic-structure has presented a dilemma between achievable accuracy and length-scale. Quantum many-body (QMB) methods realize quantum accuracy but fail to scale. Density functional theory (DFT) scales favorably but remains far from quantum accuracy. In this talk, we present a framework that addresses this dilemma by use of three interconnected modules: (i) invDFT: a methodological advance in inverse DFT linking QMB methods to DFT; (ii) MLXC: a machine-learned density functional trained with invDFT data; (iii) DFT-FE-MLXC: an adaptive higher-order spectral finite-element (FE) based DFT implementation that integrates MLXC with efficient solver strategies and HPC innovations in FE-specific dense linear algebra, mixed-precision algorithms, and asynchronous compute-communication. We demonstrate that our MLXC functionals provide an accuracy commensurate with QMB methods in ground-state energies, and the DFT-FE-MLXC framework attains an unprecedented performance of 659.7 PFLOPS (43.1% peak FP64 performance) on 619,124 electrons using 8,000 GPU nodes of the OLCF Frontier supercomputer (2023 ACM Gordon Bell Award). We will also discuss our experience and challenges in performing the above HPC optimizations targeting exascale architectures and in conducting large-scale simulations on Frontier. Finally, we will provide an outlook on the broad impact of this work on computational materials science, and discuss our ongoing and future work in further pushing the accuracy frontier of ML-XC.
This is joint work with Vishal Subramanian (U. Mich.); Vikram Gavini (U. Mich.) Gourab Panigrahi (IISc); Phani Motamarri (IISc); Paul M. Zimmerman (U. Mich)
Joining Information: A Zoom link and calendar invite will be sent to OLCF users approximately one week before the event.