By a News Reporter-Staff News Editor at Physics Week -- Researchers detail new data in Computational Physics. According to news originating from Berkeley, California, by VerticalNews correspondents, research stated, "We present a new divide-and-conquer algorithm to efficiently evaluate the Coulomb interaction in a large system, which is an essential part of self-consistent first-principle calculations. The total Coulomb potential phi(r) = 1/vertical bar r vertical bar is divided into a short range part phi(S)(r) and a smooth long range part phi(L)(r)."
Our news journalists obtained a quote from the research from the University of California, "The system is divided into many cuboids, with a small box defined for each cuboid plus a buffer region. For the short range part, the interaction convolution integral is calculated directly using a Fast Fourier Transformation (FFT) in the small box. For the smooth long range part, the convolution integral is evaluated by a global FFT but on a coarse grid. The conversion between the dense grid and coarse grid values is done using small box FFTs with proper mask functions. Using this small box FFT method, the total Coulomb potentials of test quantum dot systems on 480(3) grid and 2400(3) grid are calculated. For the 2400(3) grid case, the calculation is carried out by tens of thousands of processors with a computational speed up close to 10 times when compared with direct global FFT calculations using the FFTW package with the maximumly allowed number of processors."
According to the news editors, the research concluded: "The maximum relative error is 4 x 10(-5) while the absolute error is less than 0.1 meV."
For more information on this research see: A small box Fast Fourier Transformation method for fast Poisson solutions in large systems. Computer Physics Communications, 2013;184(12):2693-2702. Computer Physics Communications can be contacted at: Elsevier Science Bv, PO Box 211, 1000 Ae Amsterdam, Netherlands. (Elsevier - www.elsevier.com; Computer Physics Communications - www.elsevier.com/wps/product/cws_home/706710)
The news correspondents report that additional information may be obtained from X.W. Jiang, University of California, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720, United States. Additional authors for this research include S.S. Li and L.W. Wang.
Keywords for this news article include: Berkeley, California, United States, Computational Physics, North and Central America
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