hi steven, thanks for that. I actually tried a version of this after googling around and remembering that someone had suggested the faster log() function on a previous performance question for a different project: https://groups.google.com/d/msg/julia-users/dl_ysr1TdXE/bxY3VXisZugJ
I currently use mylog(x::Float64) = ccall((:log, "libm"), Float64, (Float64,), x) myexp(x::Float64) = ccall((:exp, "libm"), Float64, (Float64,), x) and I do myexp(parameter * mylog(x) ) and it does make a sizeable difference. I'll try your version right now. do you think this log issue may be worth a mention in the performance tips section of the manual? I would have never guessed that there could be a fast/slow issue with such basic functions. Little do I know! Best Florian On Wednesday, 16 July 2014 20:10:46 UTC+1, Steven G. Johnson wrote: > > If you know that x is never negative, the fastest method on my machine is > currently > > ccall(:exp, Cdouble, (Cdouble,), 1.4 * ccall(:log, Cdouble, (Cdouble,), > y)) >
