Beyond Walkers in Stochastic Quantum Chemistry: Reducing Error using Fast Randomized Iteration
Abstract
We introduce a family of methods for the full configuration interaction problem in quantum chemistry, based on the fast randomized iteration (FRI) framework [L.-H. Lim and J. Weare, SIAM Rev. 59, 547 (2017)]. These methods, which we term "FCI-FRI," stochastically impose sparsity during iterations of the power method and can be viewed as a generalization of full configuration interaction quantum Monte Carlo (FCIQMC) without walkers. In addition to the multinomial scheme commonly used to sample excitations in FCIQMC, we present a systematic scheme where excitations are not sampled independently. Performing ground-state calculations on five small molecules at fixed cost, we find that the systematic FCI-FRI scheme is 11 to 45 times more statistically efficient than the multinomial FCI-FRI scheme, which is in turn 1.4 to 178 times more statistically efficient than the original FCIQMC algorithm.
Cite
@article{arxiv.1905.00995,
title = {Beyond Walkers in Stochastic Quantum Chemistry: Reducing Error using Fast Randomized Iteration},
author = {Samuel M. Greene and Robert J. Webber and Jonathan Weare and Timothy C. Berkelbach},
journal= {arXiv preprint arXiv:1905.00995},
year = {2023}
}
Comments
19 pages, 7 figures