matplotlib-users Mailing List for matplotlib

Hi!
I'm being dense here and I'm hoping some one can help me out.
I had 0.91.1 from http://www.pythonmac.org/packages/py25-fat/index.html
I went to install the shiny new version of matplotlib (0.98.3) on my mac using 
the .egg from sourceforge.
I assumed that the .egg is a binary version of matplotlib, but the installer 
started to download a source tarball from sourceforge. It then failed because I 
don't have a bunch of libraries like png etc.
I then tried with the --no-deps option on easy_install and it timed out.
Well, I wanted to see how badly my install was borked and I ran ipython, 
imported matplotlib and checked the version and the date.
In [3]: matplotlib.__version__
Out[3]: '0.98.3'
In [4]: matplotlib.__date__
Out[4]: '$Date: 2008年07月31日 15:08:08 -0400 (2008年7月31日) $'
eh? It installed?
Then I ran some of my scripts and it turns out those work fine too!
I've been trying to understand:
1. Why the .egg would need to compile from source
2. Why the .egg works properly even though dependencies were missing and the 
compile failed
Yours in astonishment
-kg

Just a note to say I like the new webpage layout and design! :) -kg

On Sun, Aug 10, 2008 at 8:06 AM, Boris Barbour <ba...@en...> wrote:
>
> Hi,
>
> I have lots of data acquired via analogue to digital conversion. The data is
> consequently represented as integers (often 16 bit resolution). To obtain the
> correct signal and plot it, these data must of course be multiplied by a
> floating point scale factor. This seems potentially wasteful of resources
> (time and memory), especially as I would prefer to keep the original data
> untouched.
>
> It occurs to me that a more efficient plotting method would be to plot the
> original data but scale the axes by the appropriate factor. In that way a
> simple numpy array view could be passed to plot. Does a method for doing this
> exist? I think I can do it in a rather convoluted way by plotting the
> original data and then superimposing empty axes at the adjusted scale.
> However, I haven't yet tested this and I'm a bit skeptical about the overhead
> of two plots. Another possibility might be the units mechanism, but according
> to the documentation that is discouraged, and it might be awkward to
> implement.
The easiest way is to define a custom formatter -- this is responsible
for taking your numeric data and converting it to strings for the tick
labels and navigation toolbar coordinate reporting. Eg
 import numpy as np
 import matplotlib.pyplot as plt
 import matplotlib.ticker as ticker
 t = np.arange(1000)*0.01
 s = (np.random.rand(1000)*4096).astype(int)
 # this controls the formatting of the tick labels
 class VoltFormatter(ticker.Formatter):
 """
 take input and convert to +/- 5V 0->-5, 2048->0, 4096->5
 """
 def __call__(self, x, pos=None):
 return '%1.2f'%(5*(x-2048)/4096.)
 formatter = VoltFormatter()
 fig = plt.figure()
 ax = fig.add_subplot(111)
 ax.plot(t, s)
 ax.yaxis.set_major_formatter(formatter)
 plt.show()
One problem with this solution is that the tick choices are poor,
since the tick locator doesn't know where to put multiple of volts.
To solve this, you can write your own locator, eg as described in the
user's guide, to place ticks on multiples of the integer scale.
But as Eric notes, mpl will be converting your data under the hoods to
doubles anyway, so you won't be getting any space and cpu savings

Boris Barbour wrote:
> Hi,
> 
> I have lots of data acquired via analogue to digital conversion. The data is 
> consequently represented as integers (often 16 bit resolution). To obtain the 
> correct signal and plot it, these data must of course be multiplied by a 
> floating point scale factor. This seems potentially wasteful of resources 
> (time and memory), especially as I would prefer to keep the original data 
> untouched.
I don't understand this last clause; scaling your original integer data 
prior to plotting does not in any way inhibit your storage and use of 
that original integer data.
> 
> It occurs to me that a more efficient plotting method would be to plot the 
> original data but scale the axes by the appropriate factor. In that way a 
> simple numpy array view could be passed to plot. Does a method for doing this 
> exist? I think I can do it in a rather convoluted way by plotting the 
> original data and then superimposing empty axes at the adjusted scale. 
> However, I haven't yet tested this and I'm a bit skeptical about the overhead 
> of two plots. Another possibility might be the units mechanism, but according 
> to the documentation that is discouraged, and it might be awkward to 
> implement.
> 
> If the possibility doesn't exist, I wonder whether it might be feasible - and 
> not too difficult - to add to the axis methods? One could add a scale 
> parameter with a default value of 1 that should not affect existing code.
For ordinary plots in matplotlib the data will be converted to double 
precision anyway, and the time required for you to do your own scaling 
and conversion is utterly negligible compared to the total plotting 
time. I don't think it will make any difference in memory usage, 
either. Matplotlib uses asarray(), so there will not be a copy if the 
input is already a double precision array.
It sounds like you may be thinking about optimizations in the wrong 
place. Are you actually running up against speed or memory problems?
Eric

On Sun, Aug 10, 2008 at 7:29 AM, Charlie Moad
> Can you search your system and see if you have that dll installed somewhere.
> Most likely you will. If you find it, go to the command prompt and change
> to the directory where the dll is. Then run this command:
> Regsvr32 msvcp71.dll
Thanks for the suggestion.
I didn't have msvcp71.dll on my system, so I went here to download it:
http://www.driverskit.com/dll/msvcp71.dll/2371.html
Once I placed it in the python directory, C:\Python25 (next to the
msvcr71.dll), it worked fine.
Perhaps the matplotlib installer for 64-bit Vista/Windows 2008 (if
there ever is one) should include this file (or check for it)?
Thanks again for the help!
> - Charlie
Adam
-- 
"Invincibility is in oneself, vulnerability in the opponent." -- Sun Tzu

What is surprising is that this is the library Python uses, so it must
be located at c:\pythonXXX. This path should be in the PATH variable.
So the system finds the library, but not python ??
Matthieu
2008年8月10日 Adam Getchell <ada...@gm...>:
> Just installed matplotlib, it doesn't plot the basic plot.py:
>
> from pylab import *
> plot([1,2,3])
> show()
>
> Here's the results:
>
> C:\Projects\Python>python simple-plot.py --verbose-helpful
> $HOME=X:\
> CONFIGDIR=X:\.matplotlib
> matplotlib data path C:\Python25\lib\site-packages\matplotlib\mpl-data
> loaded rc file C:\Python25\lib\site-packages\matplotlib\mpl-data\matplotlibrc
> matplotlib version 0.98.3
> verbose.level helpful
> interactive is False
> units is False
> platform is win32
>
> I also get a popup window with this text:
>
> "This application has failed to start because MSVCP71.dll was not found.
> Re-installing the application may fix this problem."
>
> As far as I can tell, this is a Visual C++ library from .NET 2003.
>
> My laptop is running Windows 2008 (64-bit) with the .NET 3.0 framework.
>
> I have already removed site-packages/matplotlib and reinstalled, with
> the same results.
>
> Let me know if I should be reporting anything else not listed on:
>
> http://matplotlib.sourceforge.net/faq.html
>
> Thanks!
>
> Adam
> --
> "Invincibility is in oneself, vulnerability in the opponent." -- Sun Tzu
>
> -------------------------------------------------------------------------
> 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
>
-- 
French PhD student
Website : http://matthieu-brucher.developpez.com/
Blogs : http://matt.eifelle.com and http://blog.developpez.com/?blog=92
LinkedIn : http://www.linkedin.com/in/matthieubrucher

Can you search your system and see if you have that dll installed somewhere.
 Most likely you will. If you find it, go to the command prompt and change
to the directory where the dll is. Then run this command:
Regsvr32 msvcp71.dll
(I don't know if your 64-bit machine uses the command Regsvr64, so try that
too)
- Charlie
On Sun, Aug 10, 2008 at 2:50 AM, Adam Getchell <ada...@gm...>wrote:
> Just installed matplotlib, it doesn't plot the basic plot.py:
>
> from pylab import *
> plot([1,2,3])
> show()
>
> Here's the results:
>
> C:\Projects\Python>python simple-plot.py --verbose-helpful
> $HOME=X:\
> CONFIGDIR=X:\.matplotlib
> matplotlib data path C:\Python25\lib\site-packages\matplotlib\mpl-data
> loaded rc file
> C:\Python25\lib\site-packages\matplotlib\mpl-data\matplotlibrc
> matplotlib version 0.98.3
> verbose.level helpful
> interactive is False
> units is False
> platform is win32
>
> I also get a popup window with this text:
>
> "This application has failed to start because MSVCP71.dll was not found.
> Re-installing the application may fix this problem."
>
> As far as I can tell, this is a Visual C++ library from .NET 2003.
>
> My laptop is running Windows 2008 (64-bit) with the .NET 3.0 framework.
>
> I have already removed site-packages/matplotlib and reinstalled, with
> the same results.
>
> Let me know if I should be reporting anything else not listed on:
>
> http://matplotlib.sourceforge.net/faq.html
>
> Thanks!
>
> Adam
> --
> "Invincibility is in oneself, vulnerability in the opponent." -- Sun Tzu
>
> -------------------------------------------------------------------------
> 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
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>

Hi,
I have lots of data acquired via analogue to digital conversion. The data is 
consequently represented as integers (often 16 bit resolution). To obtain the 
correct signal and plot it, these data must of course be multiplied by a 
floating point scale factor. This seems potentially wasteful of resources 
(time and memory), especially as I would prefer to keep the original data 
untouched.
It occurs to me that a more efficient plotting method would be to plot the 
original data but scale the axes by the appropriate factor. In that way a 
simple numpy array view could be passed to plot. Does a method for doing this 
exist? I think I can do it in a rather convoluted way by plotting the 
original data and then superimposing empty axes at the adjusted scale. 
However, I haven't yet tested this and I'm a bit skeptical about the overhead 
of two plots. Another possibility might be the units mechanism, but according 
to the documentation that is discouraged, and it might be awkward to 
implement.
If the possibility doesn't exist, I wonder whether it might be feasible - and 
not too difficult - to add to the axis methods? One could add a scale 
parameter with a default value of 1 that should not affect existing code.
Boris

Just installed matplotlib, it doesn't plot the basic plot.py:
from pylab import *
plot([1,2,3])
show()
Here's the results:
C:\Projects\Python>python simple-plot.py --verbose-helpful
$HOME=X:\
CONFIGDIR=X:\.matplotlib
matplotlib data path C:\Python25\lib\site-packages\matplotlib\mpl-data
loaded rc file C:\Python25\lib\site-packages\matplotlib\mpl-data\matplotlibrc
matplotlib version 0.98.3
verbose.level helpful
interactive is False
units is False
platform is win32
I also get a popup window with this text:
"This application has failed to start because MSVCP71.dll was not found.
Re-installing the application may fix this problem."
As far as I can tell, this is a Visual C++ library from .NET 2003.
My laptop is running Windows 2008 (64-bit) with the .NET 3.0 framework.
I have already removed site-packages/matplotlib and reinstalled, with
the same results.
Let me know if I should be reporting anything else not listed on:
http://matplotlib.sourceforge.net/faq.html
Thanks!
Adam
-- 
"Invincibility is in oneself, vulnerability in the opponent." -- Sun Tzu