Basic HTML version of Foils prepared April 22 2000

Foil 27 Performance of Simplest Parallel DIT FFT III

From Parallel FFT and use in PDE Solvers Computational Science Class CPS615 -- Winter Semester 2000. by Geoffrey C. Fox
Tparallel (phases d-P? p< d) = N(Tcalc+Tcomm)/(Nproc) and again this is perfectly parallel (load balanced)
Tcomm is time to swap one complex word between 2 processors (to reduce latency this would be done as a block transfer of N/Nproc words)
Tcalc = T+ + T* as each processor must multiply and add/subtract. Note this implies that one loses parallelism in multiplication as both processors must do it.
Communication overhead fcomm = Tparallel *Nproc/Tsequential -1

© 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 Mon Apr 24 2000