Hmm reading code i verified that i can gain a 10% writing:
imd dSquared = sqrt(dx ^^ 2 + dy ^^ 2 + dz ^^ 2);
imd mag = dt / (dSquared * dSquared^^2);
Around line 115. Give it a try...
Il giorno gio, 24/11/2011 alle 22.37 -0500, bearophile ha scritto:
> This is the nbody benchmark of the Shootout site:
> http://shootout.alioth.debian.org/u32/performance.php?test=nbody
>
> The faster version is a Fortran one, probably thanks to vector operations
> that allow a better SIMD vectorization.
>
> This is the C++ version:
> http://shootout.alioth.debian.org/u32/program.php?test=nbody&lang=gpp&id=1
>
> C++ version compiled with:
> g++ -Ofast -fomit-frame-pointer -march=native -mfpmath=sse -msse3 --std=c++0x
> An input parameter is n= 3_000_000 (but use a larger number if therun time is
> too much small, like 10 millions or more).
>
> First D2 version (serial):
> http://codepad.org/AdRSm2wP
>
> Second D2 version, three times slower thanks to vector ops, more similar to
> the Fortran version:
> http://codepad.org/7O3mz9en
>
> Is someone willing to take two (or more) timings using LDC 2 compiler (I have
> LDC1 only, beside DMD)? I'd like to know how much time it takes to run the
> first D version *compared* to the C++ version :-) If you time the second D2
> version too, then it's better.
>
> Bye and thank you,
> bearophile
