CP2K is an open-source program written in Fortran 95 for atomistic and molecular simulation. The code is most well-known for it's implementation of the Quickstep linear scaling DFT algorithm, but has been designed in an extensible and efficient manner thus allowing users a wide choice of simulation methods from classical, semi-empirical and DFT to Hartree-Fock and the recently added Møller-Plesset second order perturbation theory (MP2). CP2K consists of over 800,000 lines of code and is developed by a distributed team of researchers, mostly based in Switzerland, but also including the UK.
CP2K is the third most heavily-used code on HECToR (data from 21 Dec 2010 - 3 October 2011), consuming 8.48% (731193 AUs) of system usage, behind only CASTEP (9.21%) and VASP (12.11%). Therefore we believe the work done under dCSE funding greatly impacts the scientific output of HECToR as a whole. Section 3.3 of this report advises HECToR users how they can achieve the best possible performance from CP2K.