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arXiv · 1601.00865

Understanding and Improving the Efficiency of Full Configuration Interaction Quantum Monte Carlo

W. A. Vigor·J. S. Spencer·M. J. Bearpark·A. J. W. Thom
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Abstract

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 timestep 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.

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W. A. Vigor, J. S. Spencer, M. J. Bearpark, A. J. W. Thom. 2016-03-14. Understanding and Improving the Efficiency of Full Configuration Interaction Quantum Monte Carlo. https://doi.org/10.1063/1.4943113

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