Re: [boost] Boost SIMD beta release

Subject: Re: [boost] Boost SIMD beta release
From: Peter Dimov (lists_at_[hidden])
Date: 2012-12-20 18:36:23

Mathias Gaunard wrote:
> I had forgotten there was a variant of std::transform with two inputs too.
>
> But then there is not one for three inputs or more. The only way you have 
> to use an arbitrary amount of inputs is to use a zip_iterator

You can build three inputs over two (but not over one):

    d = s + s2 + s3;

becomes

    d = s + s2;
    d = d + s3;

It's not exactly the same, performance-wise, but the point is that two 
inputs are a necessary primitive, and three inputs are an optimization.