PHoToNs--A Parallel Heterogeneous & Threads oriented code for
  cosmological N-body simulation
  We introduce a new code for cosmological simulations, PHoToNs, which has
features on performing massive cosmological simulations on heterogeneous high
performance Computer (HPC) and threads oriented programming. PHoToNs adopts a
hybrid scheme to compute gravity force, with the conventional PM to compute the
long-range force, the Tree algorithm to compute the short range force, and the
direct summation PP to compute the gravity from very close particles. A
self-similar space filling Peano-Hilbert curve is used to decompose computing
domain. Threads programming is highly used to more flexibly manage the domain
communication, PM calculation and synchronization, as well as Dual Tree
Traversal on the CPU+MIC platform. The scalability of the PHoToNs performs well
and the efficiency of PP kernel achieves 68.6% of peak performance on MIC and
74.4% on CPU platforms. We also test the accuracy of the code against the much
used Gadget-2 in the community and found excellent agreement.
