Horizontal vectorization of electron repulsion integrals |
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| Authors: | Benjamin P. Pritchard Edmond Chow |
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| Affiliation: | School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia |
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| Abstract: | We present an efficient implementation of the Obara–Saika algorithm for the computation of electron repulsion integrals that utilizes vector intrinsics to calculate several primitive integrals concurrently in a SIMD vector. Initial benchmarks display a 2–4 times speedup with AVX instructions over comparable scalar code, depending on the basis set. Speedup over scalar code is found to be sensitive to the level of contraction of the basis set, and is best for  quartets when lD = 0 or  , which makes such a vectorization scheme particularly suitable for density fitting. The basic Obara–Saika algorithm, how it is vectorized, and the performance bottlenecks are analyzed and discussed. © 2016 Wiley Periodicals, Inc. |
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| Keywords: | electron repulsion integrals two‐electron integrals vectorization Obara– Saika horizontal vectorization SIMD |
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