For instance:
When at http://pywavelets.readthedocs.org/en/latest/ref/idwt-inverse-discrete-wavelet-transform.html?highlight=waverec#pywt.waverec if i click the left tab link below edit this document, and then the link for supposedly the source code for the transform, it takes me to https://github.com/nigma/pywt/blob/develop/doc/source/ref/idwt-inverse-discrete-wavelet-transform.rst instead.

I was able to compile the master branch after using 2to3, but it won't import:

In [148]: import pywt
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
/home/me/<ipython-input-148-ea1b55fe832f> in <module>()
----> 1 import pywt

/home/me/.local/lib64/python3.2/site-packages/pywt/__init__.py in <module>()
     11 """
     12 
---> 13 import _pywt, multilevel, multidim, wavelet_packets, functions
     14 from _pywt import *
     15 from multilevel import *

ImportError: No module named _pywt

waverec sometimes generates a reconstruction that is a different length from the data passed to wavedec. For example, the haar decomposition of a 21775 length vector is reconstructed as a 21776 length vector.

First of all, thanks for a very useful module! I'm very new to wavelets, so please forgive me if this is a stupid question.

Is there a reason there isn't an implementation of iswt and iswt2 in pywt? I've seen code for iswt on the Google Groups discussion, but I really want to quickly try out denoising images with SWT, for which I need an implementation of iswt2.

Any chance that you've got that code somewhere but not yet committed it?!?

Hi,
I am trying to implement some wavelet analysis in Python for some R code wrote previously.

One function used in earlier R version code is discrete wavelet variance estimation ( 'wmtsa', page69,http://cran.r-project.org/web/packages/wmtsa/wmtsa.pdf). But I couldn't find equivalent function to implement in pywt package. Does any one knows alternative solution to that if I want to implement the similar function in Python?

Thanks!
Tao

Hi @nigma, as you may have seen on my repo the activity has further picked up and we've decided to start creating new releases: https://github.com/rgommers/pywt/issues/61. We're planning on doing a v0.3.0 release which is fully backwards compatible and with Python 3.x support this weekend. And quickly after that a v0.4.0 with more new features and refactoring.

Our question is whether you are okay with giving us (one or more of me, @kwohlfahrt, @grlee77 and @aaren) access to https://pypi.python.org/pypi/PyWavelets so we can put those releases there. That would be friendlier to users than renaming the repo and making it really a fork.

As I understand it, Cython went through a change recently. Pywt no longer compiles with the latest Cython unless "src/_pywt.pyx" changes new to cinit.

Now, I don't know Cython well enough myself to know this for myself. I just know that another project "https://code.google.com/p/pyffmpeg/issues/detail?id=44" comment #3 stated flatly that this change needs to take place, and pywt compiles after I make the change.

Using updated cygwin, with "pip" updated Cython.

I'm using wavelet transform for crop phenology detection. In this i'm using Modis ndvi time series (9 months 8-days composite). I want to apply wavelet transform with scale 32. I know to apply wavelet transform. What i want to know is how to give scaling parameter.

Thanks in advance
Rajasivaranjan

why does pywt.dwt(np.arange(8),'db2') return two arrays of size 5 each? As far as I understand the DWT should always do a downsampling of size 2, no matter the length of the filter... Am I missing something?

EDIT: sorry, saw the official repo has moved. Maybe it would be best to delete this one?

In the maximum level decomposition function there is some random code checking how many times the input is divisible by 2.

I believe this is a bug.

I cannot install the module. Trying from pip repositories:

pip3 install pywt --pre
Collecting pywt
  Could not find a version that satisfies the requirement pywt (from versions: )
No matching distribution found for pywt

OK. I clone it from github and run pip3 install .. Error:

    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 20, in <module>
      File "/var/folders/97/527pmsxx5nb7_vfnb8621nqm0000gn/T/pip-gfrdmja_-build/setup.py", line 14, in <module>
        from util import commands
      File "/private/var/folders/97/527pmsxx5nb7_vfnb8621nqm0000gn/T/pip-gfrdmja_-build/util/commands.py", line 25, in <module>
        import templating
    ImportError: No module named 'templating'

I guess it is not specified as a dependency explicitly. When I try to install templating, I get the same error:

pip3 install templating
Collecting templating
  Could not find a version that satisfies the requirement templating (from versions: )
No matching distribution found for templating

As i cannot find templating repository I post it here

Pywt.upcoef can implement a layer of decomposition and reconstruction of wavelets in Python, but after multi-layer decomposition, it is wrong to reconstruct data.

The following information is collected during installation using pip. Similar massage is also received while installing using git cloned file.

Collecting pywavelets
Using cached PyWavelets-0.2.2.zip
Complete output from command python setup.py egg_info:
Traceback (most recent call last):
File "", line 20, in
File "/private/var/folders/6z/13s_74351fvdz6zfd2np0zdm0000gn/T/pip-build-8507a3rq/pywavelets/setup.py", line 14, in
from util import commands
File "/private/var/folders/6z/13s_74351fvdz6zfd2np0zdm0000gn/T/pip-build-8507a3rq/pywavelets/util/commands.py", line 25, in
import templating
ImportError: No module named 'templating'

----------------------------------------

Command "python setup.py egg_info" failed with error code 1 in /private/var/folders/6z/13s_74351fvdz6zfd2np0zdm0000gn/T/pip-build-8507a3rq/pywavelets

Hi,

I noticed that horizontal and vertical bands may be switched around in wavedec2. Here is some IPython notebook code to reproduce this:

import numpy as np
import pywt
from scipy.misc import imread, imsave
from skimage.draw import polygon
import matplotlib.pyplot as plt
%matplotlib inline

img = np.zeros((256, 256))

poly1 = np.array((
        (50, 50),
        (50, 100),
        (100, 100),
        (100, 50)
    ))

poly2 = np.array((
        (150, 100),
        (100, 150),
        (150, 200),
        (200, 150),
    ))

rr, cc = polygon(poly1[:, 0], poly1[:, 1], img.shape)
img[rr, cc] = 1

rr, cc = polygon(poly2[:, 0], poly2[:, 1], img.shape)
img[rr, cc] = 1

db4 = pywt.Wavelet('db4')
img_w = pywt.wavedec2(img, db4, mode='sym', level=1)

fig1, ((ax1, ax2), (ax3, ax4)) = plt.subplots(2, 2)

ax1.imshow(np.absolute(img_w[0]), cmap=plt.cm.gray)
ax1.axis('off')
ax1.set_title('Approximation')

ax2.imshow(np.absolute(img_w[1][0]), cmap=plt.cm.gray)
ax2.axis('off')
ax2.set_title('Horizontal detail')

ax3.imshow(np.absolute(img_w[1][1]), cmap=plt.cm.gray)
ax3.axis('off')
ax3.set_title('Vertical detail')

ax4.imshow(np.absolute(img_w[1][2]), cmap=plt.cm.gray)
ax4.axis('off')
ax4.set_title('Diagonal detail')

There doesn't seem to be any way to get information about what version of pywt is in use at runtime.
The usual way to get version information from a module is via a module attribute 'version' but there is no such attribute for pywt.

BTW, the reason why I need this is because I am writing a super-installer that installs several modules (including pywt) for use with an application and I want to find out if the user already has the desired version of pywt installed.
Previously, I was creating my own version of pywt and I edited the file "init.py" in the 'pywt' sub-folder of the 'src' folder and added the following line near the top:
version = '0.2.0'
But now that I am using the supplied Windows installer, I can't do this.