Basic HTML version of Foils prepared February 25 2000

Foil 15 Status of Parallelism in Various N Body Cases

From Parallel Programming for Particle Dynamics Extra Foils Computational Science CPS615 -- Spring 2000 Semester. by Geoffrey C. Fox


1 Data Parallel approach is really only useful for the simple O(N2) case and even here it is quite tricky to express algorithm so that it is
  • both Space Efficient and
  • Captures factor of 2 savings from Newton's law of action and reaction Fij = - Fji
  • We have discussed these issues in a different foilset
2 The shared memory approach is effective for a modest number of processors in both algorithms.
  • It is only likely to scale properly for O(N2) case as the compiler will find it hard to capture clever ideas needed to make fast multipole efficient
3 Message Parallel approach gives you very efficient algorithms in both O(N2) and O(NlogN)
  • O(N2) case has very low communication
  • O(NlogN) has quite low communication

in Table To:


© Northeast Parallel Architectures Center, Syracuse University, npac@npac.syr.edu

If you have any comments about this server, send e-mail to webmaster@npac.syr.edu.

Page produced by wwwfoil on Wed Mar 1 2000