High Performance MP2 for Condensed Phase Simualations

This report describes the results of a PRACE Preparatory Access Type C project to optimise the implementation of Møller-Plesset second order perturbation theory (MP2) in CP2K, to allow it to be used efficiently on the PRACE Research Infrastructure. The work consisted of three stages: firstly serial optimisation of several key computational kernels; secondly, OpenMP implementation of parallel 3D Fourier Transform to support mixedmode MPI/OpenMP use of CP2K; and thirdly - benchmarking the performance gains achieved by new code on HERMIT for a test case representative of proposed production simulations. Consistent speedups of 8% were achieved in the integration kernel routines as a result of the serial optimisation. When using 8 OpenMP threads per MPI process, speedups of up to 10x for the 3D FFT were achieved, and for some combinations of MPI processes and OpenMP threads, overall speedups of 66% for the whole code were measured. As a result of this work, a proposal for full PRACE Project Access has been submitted