Slow performance compared to C++, ideas?

[finalpatch]

Hi,

I think you are using the version(D_SIMD) path, which is my (not 
very successful) attempt at vectorizing the thing.

change the version(D_SIMD) line to version(none) and it will use 
the scalar path, which has exactly the same dot() function as 
yours.

On Friday, 31 May 2013 at 04:29:19 UTC, Juan Manuel Cabo wrote:
> I just shaved 1.2 seconds trying with dmd by changing the dot 
> function from:
>
>     float dot(in Vec3 v1, in Vec3 v2)
>     {
>         auto t = v1.v * v2.v;
>         auto p = t.ptr;
>         return p[0] + p[1] + p[2];
>     }
>
> to:
>
>     float dot(in Vec3 v1, in Vec3 v2)
>     {
>         auto one = v1.v.ptr;
>         auto two = v2.v.ptr;
>         return one[0] * two[0]
>             + one[1] * two[1]
>             + one[2] * two[2];
>     }
>
> Before:
> 	2 secs, 895 ms, 891 μs, and 7 hnsecs
> After:
>         1 sec, 648 ms, 698 μs, and 1 hnsec
>