Hi guys...
This is code that was originally designed to work on an upgraded AMIGA A1200 using Python 2.0.x.
Unfortunately it broke inside much later versions, NOT because of the print statement/function but other minor subtleties. So this is the final result tested on various machines including the desired one.
The print(FFT) function also acts correctly, (even in Python 1.4.0 believe it or not), so there is no need to alter it for any Python version from 2.0.x to the current 3.7.0; just delete it as it is only there for this DEMO...
More information inside the code and as can be seen tested on various platforms and machines.
Hello,
Is there some type of functional way to read things in the Python shell interpreter similar to less or more in the bash (and other) command line shells?
Example:
>>> import subprocess
>>> help(subprocess)
...
...
I'm hoping so as I hate scrolling and love how less works with... (0 Replies)
i just found python 3.1 in the Ubuntu Software Center today... yes i know, i've probably been under a rock... but my question is, would installing 3.1 cause any conflicts with the 2.6 installation in terms of retro compatibility with python based apps?
i don't know if 3.1 is supposed to replace... (0 Replies)
Okay, so I have had this problem on openSUSE, and Debian systems now and I am hoping for a little help. I think it has something to do with Python but I couldn't find a proper Python area here.
I am trying to redirect the output of "ssh suse-server 'python -V'" to a file. It seems that no matter... (3 Replies)
I am working on requirement on spreadsheet in python scripting.
I have a spreadsheet containing cell values and with background color.
I am able to read the value value but unable to get the background color of that particular cell.
Actually my requirement is to read the cell value along... (1 Reply)
I don't know if anyone is interested but I have been meddling with FFT for the AMIGA.
(Sadly we AMIGAns don't have these luxuries through any scripting language.
Below is a Python snippet that uses the builtin 'cmath' module to work with the lowly
Python 2.0.1 for the AMIGA. It is part of a... (0 Replies)
Well i set myself a challenge to have an FFT function using nothing but ksh93 and awk.
It took some serious jiggery pokery and concentration with all the brackets and '$' characters but here is the result. It is RADIX 2 only, but hey, show me another UNIX shell script that does it. It IS SLOW but... (17 Replies)
Hi all,
I am trying to run below python code for connecting remote windows machine from unix to run an python file exist on that remote windows machine..
Below is the code I am trying:
#!/usr/bin/env python
import wmi
c = wmi.WMI("xxxxx", user="xxxx", password="xxxxxxx")... (1 Reply)
Hi all...
As you know I like making code backwards compatible for as many platforms as possible.
This Python script was in fact dedicated for the AMIGA A1200 using Pythons 1.4.0, 1.5.2, 1.6.0, 2.0.1, and 2.4.6 as that is all we have for varying levels of upgrades from a HDD and 4MB FastRam... (1 Reply)
Discussion started by: wisecracker
1 Replies
LEARN ABOUT DEBIAN
pdl::fft
FFT(3pm) User Contributed Perl Documentation FFT(3pm)NAME
PDL::FFT - FFTs for PDL
DESCRIPTION
FFTs for PDL. These work for arrays of any dimension, although ones with small prime factors are likely to be the quickest.
For historical reasons, these routines work in-place and do not recognize the in-place flag. That should be fixed.
SYNOPSIS
use PDL::FFT qw/:Func/;
fft($real, $imag);
ifft($real, $imag);
realfft($real);
realifft($real);
fftnd($real,$imag);
ifftnd($real,$imag);
$kernel = kernctr($image,$smallk);
fftconvolve($image,$kernel);
DATA TYPES
The underlying C library upon which this module is based performs FFTs on both single precision and double precision floating point
piddles. Performing FFTs on integer data types is not reliable. Consider the following FFT on piddles of type 'double':
$r = pdl(0,1,0,1);
$i = zeroes($r);
fft($r,$i);
print $r,$i;
[2 0 -2 0] [0 0 0 0]
But if $r and $i are unsigned short integers (ushorts):
$r = pdl(ushort,0,1,0,1);
$i = zeroes($r);
fft($r,$i);
print $r,$i;
[2 0 65534 0] [0 0 0 0]
This used to occur because PDL::PP converts the ushort piddles to floats or doubles, performs the FFT on them, and then converts them back
to ushort, causing the overflow where the amplitude of the frequency should be -2.
Therefore, if you pass in a piddle of integer datatype (byte, short, ushort, long) to any of the routines in PDL::FFT, your data will be
promoted to a double-precision piddle. If you pass in a float, the single-precision FFT will be performed.
FREQUENCIES
For even-sized input arrays, the frequencies are packed like normal for FFTs (where N is the size of the array and D is the physical step
size between elements):
0, 1/ND, 2/ND, ..., (N/2-1)/ND, 1/2D, -(N/2-1)/ND, ..., -1/ND.
which can easily be obtained (taking the Nyquist frequency to be positive) using
"$kx = $real->xlinvals(-($N/2-1)/$N/$D,1/2/$D)->rotate(-($N/2 -1));"
For odd-sized input arrays the Nyquist frequency is not directly acessible, and the frequencies are
0, 1/ND, 2/ND, ..., (N/2-0.5)/ND, -(N/2-0.5)/ND, ..., -1/ND.
which can easily be obtained using
"$kx = $real->xlinvals(-($N/2-0.5)/$N/$D,($N/2-0.5)/$N/$D)->rotate(-($N-1)/2);"
ALTERNATIVE FFT PACKAGES
Various other modules - such as PDL::FFTW and PDL::Slatec - contain FFT routines. However, unlike PDL::FFT, these modules are optional,
and so may not be installed.
FUNCTIONS
fft()
Complex FFT of the "real" and "imag" arrays [inplace].
fft($real,$imag);
ifft()
Complex inverse FFT of the "real" and "imag" arrays [inplace].
ifft($real,$imag);
realfft()
One-dimensional FFT of real function [inplace].
The real part of the transform ends up in the first half of the array and the imaginary part of the transform ends up in the second half of
the array.
realfft($real);
realifft()
Inverse of one-dimensional realfft routine [inplace].
realifft($real);
fftnd()
N-dimensional FFT (inplace)
fftnd($real,$imag);
ifftnd()
N-dimensional inverse FFT
ifftnd($real,$imag);
fftconvolve()
N-dimensional convolution with periodic boundaries (FFT method)
$kernel = kernctr($image,$smallk);
fftconvolve($image,$kernel);
fftconvolve works inplace, and returns an error array in kernel as an accuracy check -- all the values in it should be negligible.
See also PDL::ImageND::convolveND, which performs speed-optimized convolution with a variety of boundary conditions.
The sizes of the image and the kernel must be the same. kernctr centres a small kernel to emulate the behaviour of the direct convolution
routines.
The speed cross-over between using straight convolution (PDL::Image2D::conv2d()) and these fft routines is for kernel sizes roughly 7x7.
convmath
Signature: ([o,nc]a(m); [o,nc]b(m))
Internal routine doing maths for convolution
convmath does not process bad values. It will set the bad-value flag of all output piddles if the flag is set for any of the input
piddles.
cmul
Signature: (ar(); ai(); br(); bi(); [o]cr(); [o]ci())
Complex multiplication
cmul does not process bad values. It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.
cdiv
Signature: (ar(); ai(); br(); bi(); [o]cr(); [o]ci())
Complex division
cdiv does not process bad values. It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.
BUGS
Where the source is marked `FIX', could re-implement using phase-shift factors on the transforms and some real-space bookkeeping, to save
some temporary space and redundant transforms.
AUTHOR
This file copyright (C) 1997, 1998 R.J.R. Williams (rjrw@ast.leeds.ac.uk), Karl Glazebrook (kgb@aaoepp.aao.gov.au), Tuomas J. Lukka,
(lukka@husc.harvard.edu). All rights reserved. There is no warranty. You are allowed to redistribute this software / documentation under
certain conditions. For details, see the file COPYING in the PDL distribution. If this file is separated from the PDL distribution, the
copyright notice should be included in the file.
perl v5.14.2 2012-05-30 FFT(3pm)