Times are all in μs/atom. System size is 4000 atoms. Hardware is Xeon E5-2630 v3 @ 2.4 Ghz, OS is Ubuntu 12.04. The 'Initial Time' column results from the minimal amount of code changes to get the compiler working. The 'Final Time' is the time after the tuning in this post. Julia The cell version contains the same issue with array operations as the nsquared version - the computation of dd allocate