You just beat me to it! Thanks!
On Monday, April 28, 2014 3:41:36 PM UTC+2, Ivar Nesje wrote: > > Reported issue: https://github.com/JuliaLang/julia/issues/6681 > > kl. 13:56:29 UTC+2 mandag 28. april 2014 skrev Ivar Nesje følgende: >> >> It seems like Jeff was wrong in his statement in >> 32384010f<https://github.com/JuliaLang/julia/commit/32384010fd689e0b6a77ee93b24613fb0bdb008f> >> . >> >> This discussion belongs in an issue on github. Do you want to post it >> there? >> >> You can also fix the problem a little prettier by adding a () around 3 of >> the numbers. >> >> Ivar >> >> kl. 13:38:30 UTC+2 mandag 28. april 2014 skrev John Travers følgende: >>> >>> Hi all, >>> >>> I have found some odd performance scaling when summing and scaling more >>> than three complex numbers, see the difference between sum5 and sum5b in >>> this gist: https://gist.github.com/jtravs/11368929 >>> >>> Compare: >>> >>> julia> using testsums >>> julia> dosums(Complex{Float64}) >>> elapsed time: 0.022001424 seconds (28800096 bytes allocated) >>> elapsed time: 0.00194736 seconds (96 bytes allocated) >>> >>> With: >>> >>> julia> dosums(Float64) >>> elapsed time: 0.000664517 seconds (96 bytes allocated) >>> elapsed time: 0.000782516 seconds (96 bytes allocated) >>> >>> It seems that splitting the sum into maximum of three operands greatly >>> speeds up performance for Complex{Float64} whereas it has no significant >>> effect for Float64. Does anyone know why? I often have to sum and scale 5 >>> or more arrays in my codes and it would be unfortunate to have to hand >>> block them into sets of three like in sum5b in the gist. >>> >>>
