matplotlib-users Mailing List for matplotlib

There is a SciPy Cookbook here:
http://www.scipy.org/Cookbook
And also a more general Python cookbook here:
http://code.activestate.com/recipes/langs/python/
Other list members may have other resources, too, but those are two I 
use on a regular basis.
Mike
Kaushik Ghose wrote:
> Hi Everyone,
>
> As I've been learning python and using it more and more in my analysis work I've 
> been wondering where I can go to post and find code snippets for python. A 
> central file exchange, much like matlab's file exchange, would be great.
>
> I'm thinking of a very streamlined, blog like interface, where you log in, 
> upload a bunch of .py files and then write a little description of what the code 
> does and add some tags to it.
>
> So now we have a little repository where we can go and find code snippets to 
> help us learn python.
>
> Is there such a repository?
>
> Thanks
> -Kaushik
>
>
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Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

Hi Everyone,
As I've been learning python and using it more and more in my analysis work I've 
been wondering where I can go to post and find code snippets for python. A 
central file exchange, much like matlab's file exchange, would be great.
I'm thinking of a very streamlined, blog like interface, where you log in, 
upload a bunch of .py files and then write a little description of what the code 
does and add some tags to it.
So now we have a little repository where we can go and find code snippets to 
help us learn python.
Is there such a repository?
Thanks
-Kaushik

You could do something like:
def bitget(value, bit_number):
 return (value & (1 << bit_number)) != 0
which will return True or False for the given bit number, and this 
function works on numpy arrays. (Bits are numbered base-0 -- I don't 
know if that matches matlab).
Hope that helps,
Mike
Marjolaine Rouault wrote:
> Hi,
>
> I was wondering if python has the equivalent of the matlab bitget.m function.
>
> I have a large 2 dimensional variable of type uint32 which I must convert to binaries and then find if bit 23 of the binary for each point is 0 or 1. The matlab bitget function is ideal for that but I can't find much in python. The only thing I found was binary_repr which converts to a sting and can only be used for 1 point at a time.
>
> Any suggestions?
>
> Thanks, Marjolaine.
>
> 
-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

Hi,
I was wondering if python has the equivalent of the matlab bitget.m function.
I have a large 2 dimensional variable of type uint32 which I must convert to binaries and then find if bit 23 of the binary for each point is 0 or 1. The matlab bitget function is ideal for that but I can't find much in python. The only thing I found was binary_repr which converts to a sting and can only be used for 1 point at a time.
Any suggestions?
Thanks, Marjolaine.
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Thanks for the report. Indeed, it was drawing the fill over top of the 
hatch, rather than the other way around. This has now been fixed in SVN 
r6068. You can use that patch to patch your local copy, if you're not 
tracking SVN.
Cheers,
Mike
Crend King wrote:
> I tried hatch option in pylab.bar() in both matplotlib 0.98.2 and 
> 0.98.3. The hatch_demo.py in the example directory only draw four grey 
> bars, no hatch or them. However, when I try the same script on 
> matplotlib 0.91.4 (the maintainance version), it's working. I wonder 
> if it is a bug introduced recently? If so, it's good to have it fixed, 
> right?
>
> BTW: can I set the line width for the hatches?
>
> Thanks!
>
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> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
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> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> 
-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

Erik Tollerud wrote:
> I've been playing with some of the projections in matplotlib,
> recently, and have some questions/noticed some odd behavior:
>
> 1. Is there any way to activate a projection mode with the pyplot
> interface other than the subplot(111,projection='whatever') method a
> la /examples/api/custom_projection_example.py ? Along these same
> lines, is the projection feature documented in greater detail
> somewhere? About everything I've figured out has come from
> custom_projection_example.py ...
> 
There is some additional documentation in the new documentation here:
http://matplotlib.sourceforge.net/doc/html/devel/add_new_projection.html
> 2. I have a skymap I would like to plot using a particular projection
> - what I've been doing so far is specifying x and y coordinates using
> mgrid and calling contourf(x,y,data,100) to approximate this. But
> what I'd rather do is something like
> imshow(data,extent=[-pi,pi,-pi/2,pi/2]) ... when I call that with a
> projection axis activated, the projection isn't honored - the image
> just appears as a regular square box. Is there any way to get imshow
> to respect the projection?
> 
As Jae-Joon suggested, try pcolor. It will be slower (and there are no 
interpolation options), but it should use the custom projection. imshow 
is really optimized for uniform, rectilinear images.
Cheers,
Mike
-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

Jeff Whitaker wrote:
> Eric Firing wrote:
>> Jeff Whitaker wrote:
>>> Michael Roettger wrote:
>>>> Hi all,
>>>>
>>>> maybe I've misunderstood something concerning masking or quiver plots:
>>>> I want to exclude some data from a quiver plot. Here's an example:
>>>>
>>>> --------------------8<----
>>>> import numpy as N
>>>> import pylab as pl
>>>> import matplotlib.numerix.ma as ma
>>>>
>>>> # prepare data
>>>> X,Y = pl.meshgrid(range(5),range(5))
>>>> angles = pl.rand(5,5)
>>>> U = N.cos(angles)
>>>> V = N.sin(angles)
>>>>
>>>> # prepare mask
>>>> M = N.zeros((5,5), dtype='bool')
>>>> M[2,2] = True
>>>>
>>>> # apply mask
>>>> Um = ma.masked_array(U,mask=M)
>>>> Vm = ma.masked_array(V,mask=M)
>>>>
>>>> # plot
>>>> pl.quiver(X,Y,Um,Vm)
>>>> # pl.plot(range(5),Um[2],'x')
>>>>
>>>> pl.show()
>>>> ---------------------->8----
>>>>
>>>> Using the commented 'plot' command works as expected, but 'quiver' 
>>>> results in
>>>> empty axes. If I take U,V instead of Um,Vm, the arrows are drawn ..
>>>> What am I doing wrong or is there another way to exclude arrows from 
>>>> being
>>>> plotted?
>>>>
>>>> Thank you in advance,
>>>>
>>>> Michael
>>>>
>>>> 
>>>
>>> Michael: I've fixed this now in svn. If you don't want to update to 
>>> svn trunk, you can make this simple change in quiver.py
>>
>> Jeff,
>>
>> Thanks for the quick fix--it will help for now, and will work in most 
>> use cases, but it is not actually correct in general. The problem is 
>> that quiver supports input of changed values of U, V, and C on the 
>> existing X, Y grid, and these changed values can be masked arrays with 
>> different points masked. (See Quiver.set_UVC().) That is why I did not 
>> use delete_masked_points in the first place. Masked values used to be 
>> handled correctly; I suspect the bug is actually in collections, not 
>> in quiver itself. I can't track it down right now, but may be able to 
>> look at it over the weekend.
>>
>> Eric
> 
> OK Eric - I figured you'd chime in when you got a chance. Let's 
> consider it a temporary workaround then. BTW: I updated the 
> quiver_demo.py example to test the masking.
Very useful, thank you. I have removed the workaround and made a more 
consistent repair to the masked array handling. The problem came in 
when PolyCollection was changed to automatically close the path by default.
Eric
> 
> 
> -Jeff
>>
>>>
>>> --- lib/matplotlib/quiver.py (revision 6046)
>>> +++ lib/matplotlib/quiver.py (working copy)
>>> @@ -334,6 +334,12 @@
>>> def __init__(self, ax, *args, **kw):
>>> self.ax = ax
>>> X, Y, U, V, C = self._parse_args(*args)
>>> + if C is not None:
>>> + X, Y, U, V, C = 
>>> delete_masked_points(X.ravel(),Y.ravel(),U.ravel(),
>>> + V.ravel(),C.ravel())
>>> + else:
>>> + X, Y, U, V = 
>>> delete_masked_points(X.ravel(),Y.ravel(),U.ravel(),
>>> + V.ravel())
>>> self.X = X
>>> self.Y = Y
>>> self.XY = np.hstack((X[:,np.newaxis], Y[:,np.newaxis]))
>>>
>>>
>>> -Jeff
>>>
>>
> 
> 

Hey all,
When I plot using python 2.5.2 and matplotlib 0.98.3 (and 0.98.1) I 
have the following problem. If I run a script from the command line 
that plots and saves the figure, I get the default aspect ratio of (8, 
6). If, however, I close the plotting window and replot without 
exiting the python prompt and starting anew, the aspect changes to 
something like (8, 6.04). I can reliably get the (8, 6) aspect ratio 
if I quit the python prompt and load a new prompt. The problem only 
comes after I close the plot window and replot.
The new aspect ratio is consistent after it first changes. That is, if 
I plot, close the window, replot, close the window, and replot again, 
the 2nd and 3rd figures would save with the same aspect ratio while 
the first would have the one I desire. What could be the problem?
Cheers,
Josh

I tried hatch option in pylab.bar() in both matplotlib 0.98.2 and 0.98.3. The hatch_demo.py in the example directory only draw four grey bars, no hatch or them. However, when I try the same script on matplotlib 0.91.4 (the maintainance version), it's working. I wonder if it is a bug introduced recently? If so, it's good to have it fixed, right?
BTW: can I set the line width for the hatches?
Thanks!
_________________________________________________________________
See how Windows Mobile brings your life together—at home, work, or on the go.
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