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From: Stefan Behnel on 30 Jan 2010 14:28
uche, 30.01.2010 20:18:
> I got another problem after changing / to // . Yes, I am using 3.1.
>
> W.append(exp(sign * 2j * pi * i // N))
> TypeError: can't take floor of complex number.

Don't change it everywhere, just where it deals with integers. In the
above, "/" is perfectly right.

Stefan
From: uche on 30 Jan 2010 14:30
On Jan 30, 2:21 pm, Stefan Behnel <stefan...(a)behnel.de> wrote:
> Stefan Behnel, 30.01.2010 19:52:
>
> > uche, 30.01.2010 19:33:
> >> I have the following FFT python code
>
> > You didn't seriously implement an FFT in plain Python code, did you?
>
> Sorry, no, you didn't. Should have read your post a little closer.
>
> > FFTs
> > are amongst the first thing that come to my mind when I try to imagine what
> > I'd use NumPy for. (and I *never* used it!)
>
> On second thought, I'd probably use FFTW for that, and there seem to be
> Python bindings for it:
>
> http://developer.berlios.de/projects/pyfftw/
>
> Stefan

Thanks for the suggestions and site. I just wanted to know what the
heck is going wrong with this code. Please take a look at the code ,
thanks
From: uche on 30 Jan 2010 15:20
On Jan 30, 2:30 pm, uche <uraniumore...(a)gmail.com> wrote:
> On Jan 30, 2:21 pm, Stefan Behnel <stefan...(a)behnel.de> wrote:
>
>
>
>
>
> > Stefan Behnel, 30.01.2010 19:52:
>
> > > uche, 30.01.2010 19:33:
> > >> I have the following FFT python code
>
> > > You didn't seriously implement an FFT in plain Python code, did you?
>
> > Sorry, no, you didn't. Should have read your post a little closer.
>
> > > FFTs
> > > are amongst the first thing that come to my mind when I try to imagine what
> > > I'd use NumPy for. (and I *never* used it!)
>
> > On second thought, I'd probably use FFTW for that, and there seem to be
> > Python bindings for it:
>
> >http://developer.berlios.de/projects/pyfftw/
>
> > Stefan
>
> Thanks for the suggestions and site. I just wanted to know what the
> heck is going wrong with this code. Please take a look at the code ,
> thanks- Hide quoted text -
>
> - Show quoted text -

Thanks Stephan. You are the best!

Another issue:
x[a], x[b] = x[(a)] + W[(n % N)] * x[(b)], x[(a)] - W[(n % N)] * x
[(b)]
TypeError: can't multiply sequence by non-int of type 'complex'





From: Mark Dickinson on 31 Jan 2010 05:02
On Jan 30, 8:20 pm, uche <uraniumore...(a)gmail.com> wrote:
> Another issue:
>     x[a], x[b] = x[(a)] + W[(n % N)] * x[(b)], x[(a)] - W[(n % N)] * x
> [(b)]
> TypeError: can't multiply sequence by non-int of type 'complex'

With your original code, the elements of array2 are strings, and here
Python is refusing to multiply the string x[a] by the complex number W
[n % N]. Presumably you want the elements of array2 to be integers or
floats instead? (Your comments suggest integers, though I think floats
would be more natural here.)

MRAB's earlier reply suggests how to fix this:

array2 = []
for a in range(len(array)):
array2.append(int(array[a])) # note the extra int!

That works, but the code is cleaner if you iterate over the elements
of the array directly, instead of over their indices:

array2 = []
for x in array:
array2.append(int(x))

There are other ways, too: a seasoned Python user would probably
write this either as a list comprehension:

array2 = [int(x) for x in array]

.... or using the built-in map function:

array2 = map(int, array)


--
Mark
From: Mark Dickinson on 31 Jan 2010 05:07
On Jan 31, 10:02 am, Mark Dickinson <dicki...(a)gmail.com> wrote:
> Python is refusing to multiply the string x[a] by the complex number W
> [n % N].

Whoops, that should have been "x[b]", not "x[a]". Why is it that a
post-submission proofread turns up errors so much more often than a
pre-submission proofread?

--
Mark
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