[SciPy-user] PIL and gaussian_filter?

Robert Kern robert.kern@gmail....
Sat May 24 04:24:29 CDT 2008


On Sat, May 24, 2008 at 2:13 AM, Sebastian Haase <haase@msg.ucsf.edu> wrote:
> On Sat, May 24, 2008 at 5:39 AM, Robert Kern <robert.kern@gmail.com> wrote:

>> As I think I've mentioned in another thread, these masked operations
>> are inherently slow. We use iterators to do them, and this interferes
>> with the ability of the compiler to use optimized instructions. It is
>> exactly this operation that was the bottleneck in one of our programs,
>> so we wrote a C function using SSE2 instructions to do this wicked
>> fast.
> Robert,
> would it be possible, that you could post this
> "C function using SSE2 instructions" !?

Maybe. Certainly not soon. This was proprietary code.

> I'm very curious to see some SSE2. Are you saying the compiler is not
> optimizing normal code to use those instructions ?

Yup. David explains why.

> Lastly, I assume you interface to C using ctypes, right?

No, I wrote the module by hand.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
 -- Umberto Eco


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