QMC Meeting

Wednesday Feb 17, 2021, 10:30 AM → 11:30 AM America/New_York

Speaker: Jack Weber, Graduate Student, Friesner and Reichman groups at Columbia University

Title: Practical GPU implementation of a low-rank energy evaluation for multi-determinant trials in AFQMC

Abstract: We present an implementation of a low rank algorithm based on localized orbitals that reduces the scaling of key steps in the local energy evaluation for multi-determinant trials. Tests of accuracy vs full AFQMC show a systematically controllable error to within the statistical error of the method, with >90% reduction in the memory requirements for the “half rotated” integral tensor in typical transition metal complexes. We hope to use these developments to enable treatment of ever larger molecular transition metal complexes. I will additionally provide context for the presented algorithm within alternate localized methods, in particular the pair natural orbitals (PNOs) which have recently gained attention in the coupled cluster literature.