Parallel density functional theory energies using the Fourier transform Coulomb method
by Baker, J.; Fusti-Molnar, L.; Pulay, P.
The recently described Fourier transform Coulomb (FTC) algorithm for fast and accurate calculation of density functional theory (DFT) energies (Fusti-Molnar, L; Pulay, P. J. Chem. Phys. 2002, 117, 7827) has been parallelized. We present several calculations showing the speed and accuracy of our new parallel FTC energy code, comparing its performance with our standard all-integral DFT code. Although it still contains significant serial code, the parallel FTC algorithm is up to 6 times faster overall than our parallel all-integral algorithm, and well over an order of magnitude faster for computation of the Coulomb terms, with essentially no loss in accuracy. Proposed improvements should significantly increase these factors. The Coulomb energy in DFT energy calculations can now be computed accurately for large molecules and/or basis sets faster than the exchange-correlation energy.