JCPE Journal
Online ISSN : 1883-8367
Print ISSN : 1344-9826
ISSN-L : 1344-9826
Computing Methods for the Auxiliary s-type Integrals [0](m) by a Molecular Orbital Special-Purpose Machine MOEngine
Hajime TakashimaTakashi AmisakiSo YamadaShinjiro InabataNobuaki MiyakawaShigeru ObaraKazuaki MurakamiKunihiro KitamuraKazutoshi TanabeUmpei Nagashima
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2001 Volume 13 Issue 4 Pages 241-250


In ab initio molecular orbital calculations, two-electron integral computing timesaccount for more than 99 % of the total computing times. We are now developing a special-purpose machine MOEngine, which accelerates the calculations of two-electron integrals with high-performance and cost-effectiveness. Methods for two-electron integral calculations consist of mainly two steps, 1) computing auxiliary s-type integrals [0](m), 2) computing two-electron integrals by using [O] (m). MOEngine accelerates the step 2) by the Obara's recurrence formula. This is very effective when we compute the integrals in which each orbital has high total angular momentum, like [dd|dd]. However, these recurrence calculation steps 2) is quite less when we compute the integrals in which each orbital has low total angular momentum, like [ss|ss] and [ps|ss]. Here we discuss the efficient and high-performance computing methods for the auxiliary s-type integrals [O](m) by MOEngine.

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