Understanding and improving the efficiency of full configuration interaction quantum Monte Carlo

Journal Article · Mon Mar 07 04:00:00 EST 2016 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4943113· OSTI ID:22660879

Vigor, W. A.; Bearpark, M. J. ^[1]; Spencer, J. S. ^[2]; Thom, A. J. W. ^[1]

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1. Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)
2. Department of Physics, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)

Within full configuration interaction quantum Monte Carlo, we investigate how the statistical error behaves as a function of the parameters which control the stochastic sampling. We define the inefficiency as a measure of the statistical error per particle sampling the space and per time step and show there is a sizeable parameter regime where this is minimised. We find that this inefficiency increases sublinearly with Hilbert space size and can be reduced by localising the canonical Hartree–Fock molecular orbitals, suggesting that the choice of basis impacts the method beyond that of the sign problem.

• OSTI ID: 22660879
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 9 Vol. 144; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
COMPUTERIZED SIMULATION
CONFIGURATION INTERACTION
HARTREE-FOCK METHOD
HILBERT SPACE
MONTE CARLO METHOD