I have developed the GOTPM code in the collaboration with Professors
John Dubinski and Changbom Park
while I was visiting the CITA in the early 2000's.
This originial version was published in the New Astronomy and had been open
to the public (but now closed).
In the early 2007, Prof. Changbom Park and I decided to build a new version of the GOTPM by adopting the dynamic domain decomposition (DD) in the PM part and a faster and more efficient walking on the oct-sibling tree. As a result, this newer version is faster than the original version by about 2-3 factors. The speed of the GOTPM-II is about 20,000 particles/CPU/second with the AMD Opteron (2.6 GHz) and 40,000 particles/CPU/second with the Power5 chip. Many techiniques are applied to reduce the memory usage; the pm mesh in the PM part are recycled to make local trees in the Tree part. This is accomplished by the structure exchange between PM particle and Tree particle.
Several characteristics of the codes are summarized here ;
You can download source codes here ;
You can get a concise README file here ;
Any more information on the code can be also provided if requested.