Toward linear scaling with fitted exchange–correlation terms in the LCGTO-DF method via a divide-and-conquer approach
✍ Scribed by Sor Koon Goh; Roger T. Gallant; Alain St-Amant
- Book ID
- 101252071
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 254 KB
- Volume
- 69
- Category
- Article
- ISSN
- 0020-7608
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✦ Synopsis
The conventional linear combination of Gaussian-type orbitals LCGTO Ž .
Ž . density functional DF method fits the exchange᎐correlation XC potentials and energy density within an auxiliary basis. The benefits of this approach versus straightforward numerical quadrature of the XC terms will be discussed. However, the conventional fitting procedure scales cubically with system size and is therefore ill-suited for Ž . applications on very large systems. A divide-and-conquer DAC approach to the fits of the XC terms has been developed and implemented within the DeFT DF software package. This DAC procedure will be outlined, and the results and timings of benchmark 6-31G** calculations on extended glycine polypeptides will be presented. Other changes made to DeFT's XC subroutines, necessary to achieve near-linear scaling, will also be discussed. DeFT's grids have also been refined to achieve greater precision, and a scheme using fewer points for fitting procedures and more points for numerical integrations is presented. Through our preliminary efforts, we have achieved scalings in the XC 1.4 Ž . modules no worse than N N is the number of atoms for peptides that range in size up to 83 atoms.