Re: [boost] GSoC SIMD project

Subject: Re: [boost] GSoC SIMD project
From: Joel Falcou (joel.falcou_at_[hidden])
Date: 2011-03-02 01:24:26

On 01/03/11 23:05, Antoine de Maricourt wrote:
>
>>> I have been working for two or three months now on a low level core
>>> library, but with possibly different goals. I was not that much
>>> interested into developping a comprehensive math library, but mostly
>>> into being able to target GPUs.
>>
>> We've decided that math functions (trigonometric, exponential, etc.)
>> wouldn't be in the SIMD library but only in NT2.
>>
>> While they use the SIMD library, those don't have any platform-specific
>> code anyway. (at least I believe so, haven't seen the code of all of 
>> them)
>
> Seems to be a reasonable choice.
Most trigonometric code is built on top of extension agnostic operators.
The question is really how much should we put inside Boost.Simd. We have
litterally hundreds of them and they have, for some, quite uncanny 
dependencies
to low level IEEE bit-fiddling function.

> Yes, that's what I will do. You write functions that look like 
> kernels. They are embedded inside C++ code, compiled by a regular C++ 
> compiler, and when you execute those functions, they issue dedicated 
> source code to be compile again and executed into the target runtime's 
> environment.
NT2 is more focus on compile-time code generation in every situation it can

> Does "could" mean that the library will provide support to do it in a 
> straightforward way? Or does it mean it's theoriticaly possible at 
> great expense, because that's not a library's use case?
We have such a feature planned to accomodate some embedded architecture 
where a c++ compiler is non existant..

> OK, I think my use case needs a more low level fine control, but I 
> need to know more about what NT2 will be able to do. I'll wait for the 
> doc and friendly examples.
We'll push hard tohave some, we really mean it :)

> Does this mean there is a possibility the GPU backends will not be 
> avaible as open source? or with a restricted licence?
Depends of a lot of thing, some external to us, some depending on what's 
left in the design.