On Tue, 1 Sep 2015 18:43 Phil Hodge wrote:
On 09/01/2015 11:14 AM, Oscar Benjamin wrote:
> Just use the next power of 2. Pure powers of 2 are the most efficient
> for FFT algorithms so it potentially works out better than finding a
> smaller but similarly composite size to pad
ther.Thanks.
> From: oscar.j.benja...@gmail.com
> Date: Tue, 1 Sep 2015 16:14:41 +0100
> To: numpy-discussion@scipy.org
> Subject: Re: [Numpy-discussion] Numpy FFT.FFT slow with certain samples
>
> On 1 September 2015 at 11:38, Joseph Codadeen <jdm...@hotmail.com> wrote:
>
On 09/01/2015 11:14 AM, Oscar Benjamin wrote:
> Just use the next power of 2. Pure powers of 2 are the most efficient
> for FFT algorithms so it potentially works out better than finding a
> smaller but similarly composite size to pad to. Finding the next power
> of 2 is easy to code and never a
On Tue, Sep 1, 2015 at 12:06 PM, Oscar Benjamin
wrote:
>
> On Tue, 1 Sep 2015 18:43 Phil Hodge wrote:
>
> On 09/01/2015 11:14 AM, Oscar Benjamin wrote:
> > Just use the next power of 2. Pure powers of 2 are the most efficient
> > for FFT algorithms
f it gave
a list, prioritised by number of factors.Thanks,Joseph
Date: Fri, 28 Aug 2015 17:26:32 -0700
From: stef...@berkeley.edu
To: numpy-discussion@scipy.org
Subject: Re: [Numpy-discussion] Numpy FFT.FFT slow with certain samples
On Aug 28, 2015 5:17 PM, "Pierre-Andre Noel" <noel.pierre.a
On 1 September 2015 at 11:38, Joseph Codadeen wrote:
>
>> And while you zero-pad, you can zero-pad to a sequence that is a power of
>> two, thus preventing awkward factorizations.
>
> Does numpy have an easy way to do this, i.e. for a given number, find the
> next highest
On 2015-08-28 11:51:47, Joseph Codadeen jdm...@hotmail.com
wrote:
my_1_minute_noise_with_gaps_truncated - Array len is
2646070my_1_minute_noise_with_gaps - Array len is 2649674
In [6]: from sympy import factorint In [7]:
max(factorint(2646070)) Out[7]: 367 In [8]:
max(factorint(2649674))
On 08/28/2015 02:02 PM, Joseph Codadeen wrote:
* my_1_minute_noise_with_gaps_truncated took***30.75620985s* to process.
* my_1_minute_noise_with_gaps took *22307.13917s*to process.
You didn't say how long those arrays were, but I can make a good guess
that the truncated one had a length
my_1_minute_noise_with_gaps_truncated - Array len is
2646070my_1_minute_noise_with_gaps - Array len is 2649674
Date: Fri, 28 Aug 2015 14:28:49 -0400
From: ho...@stsci.edu
To: numpy-discussion@scipy.org
Subject: Re: [Numpy-discussion] Numpy FFT.FFT slow with certain samples
On 08/28/2015
If your sequence is not meant to be periodic (i.e., if after one minute
there is no reason why the signal should start back at the beginning
right away), then you should do zero-padding. And while you zero-pad,
you can zero-pad to a sequence that is a power of two, thus preventing
awkward
On 2015-08-28 16:20:33, Pierre-Andre Noel
noel.pierre.an...@gmail.com wrote:
If your sequence is not meant to be periodic (i.e., if after one
minute there is no reason why the signal should start back at
the beginning right away), then you should do zero-padding. And
while you zero-pad,
, thanks Stefan and everyone.
From: stef...@berkeley.edu
To: numpy-discussion@scipy.org
Date: Fri, 28 Aug 2015 12:03:52 -0700
Subject: Re: [Numpy-discussion] Numpy FFT.FFT slow with certain
samples
On 2015-08-28 11:51:47, Joseph Codadeen jdm...@hotmail.com
wrote
, Joseph Codadeen wrote:
Great, thanks Stefan and everyone.
From: stef...@berkeley.edu
To: numpy-discussion@scipy.org
Date: Fri, 28 Aug 2015 12:03:52 -0700
Subject: Re: [Numpy-discussion] Numpy FFT.FFT slow with certain
samples
On 2015-08-28 11:51:47, Joseph Codadeen jdm...@hotmail.com
Great, thanks Stefan and everyone.
From: stef...@berkeley.edu
To: numpy-discussion@scipy.org
Date: Fri, 28 Aug 2015 12:03:52 -0700
Subject: Re: [Numpy-discussion] Numpy FFT.FFT slow with certain samples
On 2015-08-28 11:51:47, Joseph Codadeen jdm...@hotmail.com
wrote
Zero-padding won't help with the non-periodicity, will it? For
that you may want to window instead.
Umh, it depends what you use the FFT for. You are right Stéfan when
saying that Joseph should probably also use a window to get rid of the
high frequencies that will come from the sharp
On Aug 28, 2015 5:17 PM, Pierre-Andre Noel noel.pierre.an...@gmail.com
wrote:
I had in mind the use of FFT to do convolutions (
https://en.wikipedia.org/wiki/Convolution_theorem ). If you do not
zero-pad properly, then the end of the signal may bleed on the
beginning, and vice versa.
Ah,
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