An Efficient Implementation of Semi-numerical Computation of the Hartree-Fock Exchange Matrix on the Intel Phi Processor

In this work we present an efficient semi-numerical integral implementation specially designed for the Intel Phi processor to calculate the Hartree-Fock exchange matrix and the energy. Compared with the implementation for the CPU platform, to achieve a productive implementation one needs to focus on the efficient utilization of the SIMD(Single instruction, multiple data) processing unit and maximum cache usage in the Phi processor. For evaluating the efficiency of the implementation, we performed benchmark calculations on the buckyball molecules C60, C100, C180 and C240. For the calculations with basis set 6-311G(2df) and cc-pvtz the benchmark test shows 7-12 times of speedup on the Knight Landing Phi processor 7250 in comparison with traditional four-center electron repulsion integral calculation performed on a six-core Xeon E5-1650 CPU.