Re: [eigen] about changeset 6eb14e380

[joel falcou <joel.falcou@xxxxxx>]

On 19/08/10 13:03, Gael Guennebaud wrote:
> To make things more complicated we could also think about how to
> support packet of different sizes for the same scalar type. Indeed,
> both the NEON (for ARM) and the future AVX engines support packet of
> different sizes. 2 or 4 floats for NEON, and 4 or 8 floats for AVX.
> For dynamic sized objects it is pretty clear that supporting largest
> packets is enough. However, for small fixed sized objects it be very
> welcome to be able to instantiate packet types according to the
> context. For instance, if AVX is enabled, we still want to able to use
> packets of 4 floats to vectorize Vector4 and Matrix4. This is very
> important for what you know...
>    
It is not. In nt2, the simd packet class is native<T,X> where T is the 
scalar
type and X the extension tag. Then functions knwo which packet they are 
allowed
to mix and the configuration include w/e tag needed.