Comments about FFT



my suspicion is that the time to actually do the arithmetic will be 
dominated by the overhead associated with each arithmetic operation.
With some profiling, we could tell.
Also, shouldn't the fft work with bigfloats, etc.?
(using mpfr in lisp is the other possibility.  Let someone else worry 
about how to implement the FFT.)

RJF

Raymond Toy wrote:
> ?iga Lenar?i? wrote:
>   
>> On Aug 24, 2009, at 8:41 PM, Raymond Toy wrote:
>>     
>>> That might be expected if you're using a very recent version of SBCL
>>> (and 19f or later CMUCL).  I know in cmucl 19f, complex arithmetic uses
>>> sse2 by default, and that can be significantly faster because the
>>> operations are vectorized.  The real/imag array version will suffer
>>> quite a bit since the complex operations probably won't be vectorized.
>>>       
>> Forgot to comment on that bit -
>> I use SBCL 1.0.30 (latest) but I don't think they have imported these
>> improvements from CMUCL. 
>>     
> I think SBCL's implementation of complex arithmetic with sse2 is totally
> separate from CMUCL's implementation.
>
> Ray
>
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