[Numpy-discussion] Enhancements for NumPy's FFTs

Sturla Molden sturla@molden...
Sat Mar 14 21:26:35 CDT 2009


> On Sat, Mar 14, 2009 at 7:23 PM, Sturla Molden <sturla@molden.no> wrote:

> We can't count on C99 at this point. Maybe David will add something so we
> can use c99 when it is available.

Ok, but most GNU compilers has a __restrict__ extension for C89 and C++
that we could use. And MSVC has a compiler pragma in VS2003 and a
__restrict extension in VS2005 later versions.  So we could define a mscro
RESTRICT to be restrict in ISO C99, __restrict__ in GCC 3 and 4,
__restrict in recent versions of MSVC, and nothing elsewhere.


> I don't have a problem with this, although I not sure what npy type is
> appropriate without looking. Were you thinking of size_t? I was tempted by
> that. But why is it more efficient? I haven't seen any special
> instructions
> at the assembly level, so unless there is some sort of global optimization
> that isn't obvious I don't know where the advantage is.

I may be that my memory serves med badly. I thought I read it here, but it
does not show examples of different assembly code being generated. So I
think I'll just leave it for now and experiment with this later.

http://support.amd.com/us/Processor_TechDocs/22007.pdf

Is an npy_intp 64 bit on 64 bit systems?


Sturla Molden




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