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arXiv 1708.07913physics.comp-phcond-mat.mtrl-sci
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SQDFT:高温下大规模并行$\mathcal{O}(N)$ Kohn-Sham计算的谱求积方法

SQDFT: Spectral Quadrature method for large-scale parallel $\mathcal{O}(N)$ Kohn-Sham calculations at high temperature

Phanish Suryanarayana, Phanisri P. Pratapa, Abhiraj Sharma, John E. Pask

摘要:

我们介绍SQDFT:一个大规模并行实现的光谱求积(SQ)方法的$\mathcal{O}(N)$科恩-沙姆密度泛函理论(DFT)计算在高温下。具体来说,我们开发了一个有效的和可扩展的有限差分实现的无限细胞Clenshaw-Curtis SQ的方法,其中的无限晶体的结果是通过表达感兴趣的数量作为双线性形式或双线性形式的总和,然后近似的空间本地化的Clenshaw-Curtis求积规则。我们证明了SQDFT的准确性,显示系统收敛的能量和原子力相对于SQ参数参考对角化结果,和收敛与离散化建立平面波的结果,金属和绝缘系统。我们进一步证明,SQDFT实现了优秀的强和弱的并行缩放的计算机系统,由成千上万的处理器,接近完美的$\mathcal{O}(N)$缩放系统的大小和墙时间低至几秒钟,每个自洽场迭代。最后,我们验证了SQDFT在高温铝的大尺度量子分子动力学模拟中的准确性。

英文摘要:

We present SQDFT: a large-scale parallel implementation of the Spectral Quadrature (SQ) method for $\mathcal{O}(N)$ Kohn-Sham Density Functional Theory (DFT) calculations at high temperature. Specifically, we develop an efficient and scalable finite-difference implementation of the infinite-cell Clenshaw-Curtis SQ approach, in which results for the infinite crystal are obtained by expressing quantities of interest as bilinear forms or sums of bilinear forms, that are then approximated by spatially localized Clenshaw-Curtis quadrature rules. We demonstrate the accuracy of SQDFT by showing systematic convergence of energies and atomic forces with respect to SQ parameters to reference diagonalization results, and convergence with discretization to established planewave results, for both metallic and insulating systems. We further demonstrate that SQDFT achieves excellent strong and weak parallel scaling on computer systems consisting of tens of thousands of processors, with near perfect $\mathcal{O}(N)$ scaling with system size and wall times as low as a few seconds per self-consistent field iteration. Finally, we verify the accuracy of SQDFT in large-scale quantum molecular dynamics simulations of aluminum at high temperature.

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