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Subject: Re: [boost] [compute] GPGPU Library - Request For Feedback
From: Kyle Lutz (kyle.r.lutz_at_[hidden])
Date: 2013-03-03 09:00:47

On Sun, Mar 3, 2013 at 6:15 AM, Gabriel Redner <gredner_at_[hidden]> wrote:
> Hi Kyle,
> This looks like a very interesting library! When I have a bit of time
> I may see see if some of my simulation codes are good candidates to
> make use of your API.

Thanks! Please let me know if you encounter any problems.

> For the moment, just a few points from reading the docs:
> - Under "Lambda Expressions", I am pretty sure that "+ 4" is not the
> right way to "subtract four" :-)

Fixed. Thanks for pointing this out!

> - Like Karsten I am interested in zip iterators - my simulation code
> uses such structures heavily.

Zip iterators are a feature I have planned but haven't had time to
implement yet. Stay tuned!

> - What is the command_queue argument that appears in all of the
> algorithms? For instance here:
> the
> signature for 'copy' takes four arguments - three iterators and a
> command_queue - but the example only passes the iterators, and there
> is no other mention of command_queues.

Command queues specify the context and device for the algorithm's
execution. For all of the standard algorithms the command_queue
parameter is optional. If not provided, a default command_queue will
be created for the default GPU device and the algorithm will be
executed there.

> - Under "Vector Data Types", why floats but not doubles? Is this an
> OpenCL restriction? (sorry for the ignorance - my GPGPU knowledge is
> mostly on the CUDA side). Also, what header are they declared in?

Doubles are supported by both my library and by OpenCL. However,
doubles are not supported by all compute devices. Trying to use
doubles on a device that doesn't support them will cause a
runtime_exception to be thrown. The list under "Vector Data Types"
just gives a few examples. All of the scalar and vector data types are
declared in the "boost/compute/types.hpp" header.

Thanks for the feedback!


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