Vector performance

[Iain Buclaw]

On 12 January 2012 08:29, Manu <turkeyman at gmail.com> wrote:
> On 12 January 2012 02:46, F i L <witte2008 at gmail.com> wrote:
>>
>> Well the idea is you can have both. You could even have a:
>>
>>   Vector2!(Transition!(Vector4!(Transition!float))) // headache
>>   or something more practical...
>>
>>   Vector4!(Vector4!float) // Matrix4f
>>   Vector4!(Transition!(Vector4!float)) // Smooth Matrix4f
>>
>> Or anything like that. I should point out that my example didn't make it
>> clear that a Matrix4!(Transition!float) would be pointless compared to
>> Transition!(Matrix4!float) unless each Transition held it's own iteration
>> value. Example:
>>
>>   struct Transition(T, bool isTimer = false) {
>>
>>       T value, start, target;
>>       alias value this;
>>
>>       static if (isTimer) {
>>           float time, speed;
>>
>>           void update() {
>>               time += speed;
>>               value = start + ((target - start) * time);
>>           }
>>       }
>>   }
>>
>> That way each channel could update on it's own time frame. There may even
>> be a way to have each channel be it's own separate Transition type. Which
>> could be interesting. I'm still playing with possibilities.
>
>
> The vector's aren't quite like that.. you can't make a hardware vector out
> of anything, only things the hardware supports: __vector(float[4]) for
> instance.
> You can make your own vector template that wraps those I guess if you want
> to make a matrix that way, but it sounds inefficient. When it comes to
> writing the vector/matrix operations, if you're assuming generic code, you
> won't be able to make it anywhere near as good as if you write a Matrix4x4
> class.
>
>
>>> I think that is also possible if that's what you want to do, and I see no
>>> reason why any of these constructs wouldn't be efficient (or supported).
>>> You can probably even try it out now with what Walter has already done...
>>
>>
>> Cool, I was unaware Walter had begun implementing SIMD operations. I'll
>> have to build DMD and test them out. What's the syntax like right now?
>
>
> The syntax for the types (supporting basic arithmetic) look like
> __vector(float[4]) float4vector.. Try it on the latest GDC.
>

This will change.  I'm uploading core.simd later which has a Vector!()
template, and aliases for vfloat4, vdouble2, vint4, etc...

I don't plan on implementing vector instrinsics in the same way Walter
is doing it.

a)  GCC already prodives it's own intrinsics
b) The intrinsics I see Walter has already implemented in core.simd is
restricted to x86 line of architectures.


Regards
-- 
Iain Buclaw

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