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Fast semistochastic heat-bath configuration interaction

Cornell Affiliated Author(s)

Author

Junhao Li
Matthew Otten
Adam Holmes
Sandeep Sharma
C. Umrigar

Abstract

This paper presents in detail our fast semistochastic heat-bath configuration interaction (SHCI) method for solving the many-body Schrödinger equation. We identify and eliminate computational bottlenecks in both the variational and perturbative steps of the SHCI algorithm. We also describe the parallelization and the key data structures in our implementation, such as the distributed hash table. The improved SHCI algorithm enables us to include in our variational wavefunction two orders of magnitude more determinants than has been reported previously with other selected configuration interaction methods. We use our algorithm to calculate an accurate benchmark energy for the chromium dimer with the X2C relativistic Hamiltonian in the cc-pVDZ-DK basis, correlating 28 electrons in 76 spatial orbitals. Our largest calculation uses two billion Slater determinants in the variational space and semistochastically includes perturbative contributions from at least trillions of additional determinants with better than 10-5 Ha statistical uncertainty. © 2018 Author(s).

Date Published

Journal

Journal of Chemical Physics

Volume

149

Issue

21

URL

https://www.scopus.com/inward/record.uri?eid=2-s2.0-85058138369&doi=10.1063%2f1.5055390&partnerID=40&md5=2c065beea0bad9055f66890daadc695b

DOI

10.1063/1.5055390

Group (Lab)

Cyrus Umrigar Group

Funding Source

1445606
1534965
1800584
ACI-1445606

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