matplotlib-users Mailing List for matplotlib (Page 7)

Dear all,
I am trying to plot data on a 1:1 ratio plot to compare the data.
I can set the x and y aixs to have the same limits. but how can I set them
to have the same distance between ticks in the graph?
Thanks a lot,
chao
-- 
***********************************************************************************
Chao YUE
Laboratoire des Sciences du Climat et de l'Environnement (LSCE-IPSL)
UMR 1572 CEA-CNRS-UVSQ
Batiment 712 - Pe 119
91191 GIF Sur YVETTE Cedex
Tel: (33) 01 69 08 29 02; Fax:01.69.08.77.16
************************************************************************************

On Fri, Oct 14, 2011 at 8:52 AM, John Hunter <jd...@gm...> wrote:
> On Fri, Oct 14, 2011 at 8:46 AM, Jorge Scandaliaris
> <jor...@ya...> wrote:
>> You're right, John, it works here too with the gtkagg backend. I have just
>> noticed that I had different backend options set in matplotlib.conf and
>> matplotlibrc. My initial report refers then to the Qt4Agg backend.
>
> OK, I can confirm this too on Qt4Agg version 4.8.3.
I opened an issue here
 https://github.com/matplotlib/matplotlib/issues/525
I am no qt expert so perhaps someone else can suggest a solution. In
the gtk backend, I believe we added:
 self.canvas.grab_focus()
to support events w/o clicking on the canvas.

On Fri, Oct 14, 2011 at 8:46 AM, Jorge Scandaliaris
<jor...@ya...> wrote:
> You're right, John, it works here too with the gtkagg backend. I have just
> noticed that I had different backend options set in matplotlib.conf and
> matplotlibrc. My initial report refers then to the Qt4Agg backend.
OK, I can confirm this too on Qt4Agg version 4.8.3.

John Hunter <jdh2358@...> writes:
> 
> I am not seeing this on Linux x86_64 with backend GTKAgg version
> 2.22.0 on python 2.7. Eg, if I run:
> 
> > python simple_plot.py -dgtkagg
> 
> and then hover over the axes window (w/o clicking on it but the window
> has the focus on hover) and press 'g') the grids is toggled.
> 
> JDH
You're right, John, it works here too with the gtkagg backend. I have just
noticed that I had different backend options set in matplotlib.conf and
matplotlibrc. My initial report refers then to the Qt4Agg backend.
BTW, which of matplotlib.conf or matplotlibrc is preferred?
jorges

On Fri, Oct 14, 2011 at 7:18 AM, Jorge Scandaliaris
<jor...@ya...> wrote:
> I run Arch Linux x86_64 and I am using the GTKAgg backend. I tried both with
> IPython and python directly (2.7.2).
I am not seeing this on Linux x86_64 with backend GTKAgg version
2.22.0 on python 2.7. Eg, if I run:
 > python simple_plot.py -dgtkagg
and then hover over the axes window (w/o clicking on it but the window
has the focus on hover) and press 'g') the grids is toggled.
JDH

Benjamin Root <ben.root@...> writes:
> 
> Which backend and platform are you using?Ben Root
> 
I run Arch Linux x86_64 and I am using the GTKAgg backend. I tried both with
IPython and python directly (2.7.2).
jorges

On 10/12/11 8:20 PM, questions anon wrote:
> Hi All,
> I keep receiving a memory error when processing many netcdf files. I 
> assumed it had something to do with how I loop things and maybe needed 
> to close things off properly but I recently received an error that 
> made me think it might be because of matplotlib.
>
> In the code below I am looping through a bunch of netcdf files (each 
> file is hourly data for one month) and within each netcdf file I am 
> outputting a *png file every three hours. This works for one netcdf 
> file (therefore one month) but when it begins to process the next 
> netcdf file I receive a memory error (see below). Since I have tidied 
> some of my code up it seems to process partly into the second file but 
> then I still receive the memory error.
> I have tried a few suggestions such as:
> -Combining the dataset using MFDataset (using NETCDF4) is not an 
> option because the files do not have unlimited dimension.
> - gc.collect() but that just results in a /GEOS_ERROR: bad allocation 
> error/.
> -only open LAT and LON once (which worked)
>
> System Details:
> Python 2.7.2 |EPD 7.1-2 (32-bit)| (default, Jul 3 2011, 15:13:59) 
> [MSC v.1500 32 bit (Intel)] on win32
>
> Any feedback will be greatly appreciated as I seem to keep ending up 
> with memory errors when working with netcdf files this even happens if 
> I am using a much better computer.
>
> *Most recent error: *
> Traceback (most recent call last):
> File "C:\plot_netcdf_merc_multiplot_across_multifolders_TSFC.py", 
> line 78, in <module>
> plt.savefig((os.path.join(outputfolder, 
> 'TSFC'+date_string+'UTC.png')))
> File "C:\Python27\lib\site-packages\matplotlib\pyplot.py", line 363, 
> in savefig
> return fig.savefig(*args, **kwargs)
> File "C:\Python27\lib\site-packages\matplotlib\figure.py", line 
> 1084, in savefig
> self.canvas.print_figure(*args, **kwargs)
> File 
> "C:\Python27\lib\site-packages\matplotlib\backends\backend_wxagg.py", 
> line 100, in print_figure
> FigureCanvasAgg.print_figure(self, filename, *args, **kwargs)
> File "C:\Python27\lib\site-packages\matplotlib\backend_bases.py", 
> line 1923, in print_figure
> **kwargs)
> File 
> "C:\Python27\lib\site-packages\matplotlib\backends\backend_agg.py", 
> line 438, in print_png
> FigureCanvasAgg.draw(self)
> File 
> "C:\Python27\lib\site-packages\matplotlib\backends\backend_agg.py", 
> line 393, in draw
> self.renderer = self.get_renderer()
> File 
> "C:\Python27\lib\site-packages\matplotlib\backends\backend_agg.py", 
> line 404, in get_renderer
> self.renderer = RendererAgg(w, h, self.figure.dpi)
> File 
> "C:\Python27\lib\site-packages\matplotlib\backends\backend_agg.py", 
> line 59, in __init__
> self._renderer = _RendererAgg(int(width), int(height), dpi, 
> debug=False)
> RuntimeError: Could not allocate memory for image
>
> *Error when I added gc.collect()*
> GEOS_ERROR: bad allocation
>
> *Old error (before adding gc.collect() )*
> /Traceback (most recent call last):
> File 
> "d:/plot_netcdf_merc_multiplot_across_multifolders__memoryerror.py", 
> line 44, in <module>
> TSFC=ncfile.variables['T_SFC'][1::3]
> File "netCDF4.pyx", line 2473, in netCDF4.Variable.__getitem__ 
> (netCDF4.c:23094)
> MemoryError/
>
>
>
> from netCDF4 import Dataset
> import numpy as N
> import matplotlib.pyplot as plt
> from mpl_toolkits.basemap import Basemap
> from netcdftime import utime
> from datetime import datetime
> import os
> import gc
>
>
> shapefile1="E:/
>
> griddeddatasamples/GIS/DSE_REGIONS"
> MainFolder=r"E:/griddeddatasamples/GriddedData/InputsforValidation/T_SFC/"
> OutputFolder=r"E:/griddeddatasamples/GriddedData/OutputsforValidation"
> fileforlatlon=Dataset("E:/griddeddatasamples/GriddedData/InputsforValidation/T_SFC/TSFC_1974_01/IDZ00026_VIC_ADFD_T_SFC.nc",
> 'r+', 'NETCDF4')
> LAT=fileforlatlon.variables['latitude'][:]
> LON=fileforlatlon.variables['longitude'][:]
>
> for (path, dirs, files) in os.walk(MainFolder):
> for dir in dirs:
> print dir
> path=path+'/'
> for ncfile in files:
> if ncfile[-3:]=='.nc':
> print "dealing with ncfiles:", ncfile
> ncfile=os.path.join(path,ncfile)
> ncfile=Dataset(ncfile, 'r+', 'NETCDF4')
> TSFC=ncfile.variables['T_SFC'][1::3]
> TIME=ncfile.variables['time'][1::3]
> ncfile.close()
> gc.collect()
>
> for TSFC, TIME in zip((TSFC[:]),(TIME[:])):
> cdftime=utime('seconds since 1970年01月01日 00:00:00')
> ncfiletime=cdftime.num2date(TIME)
> print ncfiletime
> timestr=str(ncfiletime)
> d = datetime.strptime(timestr, '%Y-%m-%d %H:%M:%S')
> date_string = d.strftime('%Y%m%d_%H%M')
>
> map =
> Basemap(projection='merc',llcrnrlat=-40,urcrnrlat=-33,
> 
> llcrnrlon=139.0,urcrnrlon=151.0,lat_ts=0,resolution='i')
> x,y=map(*N.meshgrid(LON,LAT))
> map.drawcoastlines(linewidth=0.5)
> map.readshapefile(shapefile1, 'DSE_REGIONS')
> map.drawstates()
>
> plt.title('Surface temperature at %s UTC'%ncfiletime)
> ticks=[-5,0,5,10,15,20,25,30,35,40,45,50]
> CS = map.contourf(x,y,TSFC, ticks, cmap=plt.cm.jet)
> l,b,w,h =0.1,0.1,0.8,0.8
> cax = plt.axes([l+w+0.025, b, 0.025, h], )
> cbar=plt.colorbar(CS, cax=cax, drawedges=True)
>
> plt.savefig((os.path.join(OutputFolder,
> 'TSFC'+date_string+'UTC.png')))
> plt.close()
> gc.collect()
>
Try moving these lines
 map = 
Basemap(projection='merc',llcrnrlat=-40,urcrnrlat=-33,
 
llcrnrlon=139.0,urcrnrlon=151.0,lat_ts=0,resolution='i')
 x,y=map(*N.meshgrid(LON,LAT))
 map.drawcoastlines(linewidth=0.5)
 map.readshapefile(shapefile1, 'DSE_REGIONS')
 map.drawstates()
out of the loop.
-Jeff

+------------------------------------------------ Keith Hughitt ---------+
> Hi all,
> 
> Does anyone know of a good way to create a new LinearSegmentedColormap
> based off an existing one?
> 
> I have a function which attempts to generate N "optimal" color map
> indices for a given data array. In cases where the number of values
> specified in _segmentdata is the same as N, then I can simply
> copy _segmentdata and modify the indices and create a new color map. In
> many cases, however, the segment data has far fewer interpolation
> points, e.g.:
> 
> In [52]: cm.gray._segmentdata
> Out[52]:
> {'blue': ((0.0, 0, 0), (1.0, 1, 1)),
> 'green': ((0.0, 0, 0), (1.0, 1, 1)),
> 'red': ((0.0, 0, 0), (1.0, 1, 1))}
> 
> 
> Other colormaps may have an arbitrary number of interpolation points.
> Ideally, what I would like is a way to expand this into N points (e.g.
> 256) so that I use that as input for my new map.
> 
i cannot really help you with your approach, but i also think it's not
so elegant to expand cmaps.
did you try to understand the way cmaps can be defined by gradient
borders? -> http://www.scipy.org/Cookbook/Matplotlib/Show_colormaps
i.e. a friend gave me a colormap defined by points and i converted it to
something like that (by just looking at the colors):
ie_data = {
'red': ((0.00, 0.357, 0.357),
 (0.50, 1.000, 1.000),
 (0.75, 1.000, 1.000),
 (1.00, 1.000, 1.000)),
'green':((0.00, 0.467, 0.467),
 (0.50, 1.000, 1.000),
 (0.75, 0.750, 0.750),
 (1.00, 0.371, 0.371)),
'blue':((0.00, 0.800, 0.800),
 (0.50, 1.000, 1.000),
 (0.75, 0.157, 0.157),
 (1.00, 0.157, 0.157))
}
ie = matplotlib.colors.LinearSegmentedColormap('ieMap', ie_data, 256)
use it with cmap=ie
regards

Hi all,
what is the native "data" coordinate system for Arrows in 
a polar plot ?
How do I add arrows to a polar plot ?
An example would be appreciated.
fig = figure(figsize=(12,12))
ax = fig.add_subplot(111, polar=True)
Nils

On Thu, Oct 13, 2011 at 9:52 PM, Jorge Scandaliaris
<jor...@ya...>wrote:
> Hi,
>
> I am experiencing something a bit strange with 'key_press_event': The event
> is
> not detected unless I click with the mouse on the canvas (The grey area
> around
> the axis). I verified this with my own code as well as with some unmodified
> example (
>
> http://matplotlib.sourceforge.net/examples/event_handling/keypress_demo.html?highlight=key_press_event
> ).
> I built mpl from a recent revision (a few days old).
>
> Does anyone else experience this? Is this the expected behavior? I believe
> it
> was enough to have the figure window focused to get key events before, but
> I
> haven't used this feature for some time.
>
> Thanks,
>
> Jorges
>
>
Which backend and platform are you using?
Ben Root

Hi,
I am experiencing something a bit strange with 'key_press_event': The event is
not detected unless I click with the mouse on the canvas (The grey area around
the axis). I verified this with my own code as well as with some unmodified
example (
http://matplotlib.sourceforge.net/examples/event_handling/keypress_demo.html?highlight=key_press_event
).
I built mpl from a recent revision (a few days old).
Does anyone else experience this? Is this the expected behavior? I believe it
was enough to have the figure window focused to get key events before, but I
haven't used this feature for some time.
Thanks,
Jorges

Thanks,
Ben, that makes sense although I think the angles I have can be considered
the direction 'to' and I want direction 'from' so adding a negative makes
them come from the direction I need.
I should add I don't really know what flip does so will ignore that.
thanks for the responses.
On Fri, Oct 14, 2011 at 9:32 AM, Eric Firing <ef...@ha...> wrote:
> On 10/13/2011 12:22 PM, Benjamin Root wrote:
>
>>
>>
>> On Thursday, October 13, 2011, questions anon <que...@gm...
>> <mailto:questions.anon@gmail.**com <que...@gm...>>> wrote:
>> > Another quick question,
>> > I noticed that the wind direction appeared back-to-front so I have
>> added a negative to my equation as I am in the southern hemisphere. It
>> now looks correct but I wanted to check if this is the right way to do
>> this? I saw something called 'flip' for barb but nothing for quiver.
>>
>> It probably nothing to do with southern hemisphere but rather that it is
>> typical for wind data to be recorded and displayed as direction "from",
>> instead of direction "to". If you think "flip" should be available for
>> quiver(), file a feature request.
>>
>
> It looks to me like the barb "flip" is for something else entirely--it is a
> right-hand versus left-hand sort of flip. This would be inappropriate for
> quiver, which makes symmetric arrows. I would strongly oppose any proposal
> for a kwarg to reverse the direction of the arrows.
>
> Eric
>
>
>
>> Ben Root
>>
>
>

On 10/13/2011 12:22 PM, Benjamin Root wrote:
>
>
> On Thursday, October 13, 2011, questions anon <que...@gm...
> <mailto:que...@gm...>> wrote:
> > Another quick question,
> > I noticed that the wind direction appeared back-to-front so I have
> added a negative to my equation as I am in the southern hemisphere. It
> now looks correct but I wanted to check if this is the right way to do
> this? I saw something called 'flip' for barb but nothing for quiver.
>
> It probably nothing to do with southern hemisphere but rather that it is
> typical for wind data to be recorded and displayed as direction "from",
> instead of direction "to". If you think "flip" should be available for
> quiver(), file a feature request.
It looks to me like the barb "flip" is for something else entirely--it 
is a right-hand versus left-hand sort of flip. This would be 
inappropriate for quiver, which makes symmetric arrows. I would 
strongly oppose any proposal for a kwarg to reverse the direction of the 
arrows.
Eric
>
> Ben Root

On Thursday, October 13, 2011, questions anon <que...@gm...>
wrote:
> Another quick question,
> I noticed that the wind direction appeared back-to-front so I have added a
negative to my equation as I am in the southern hemisphere. It now looks
correct but I wanted to check if this is the right way to do this? I saw
something called 'flip' for barb but nothing for quiver.
It probably nothing to do with southern hemisphere but rather that it is
typical for wind data to be recorded and displayed as direction "from",
instead of direction "to". If you think "flip" should be available for
quiver(), file a feature request.
Ben Root

Another quick question,
I noticed that the wind direction appeared back-to-front so I have added a
negative to my equation as I am in the southern hemisphere. It now looks
correct but I wanted to check if this is the right way to do this? I saw
something called 'flip' for barb but nothing for quiver.
Thanks, see code below
 map = Basemap(projection='merc',llcrnrlat=-40,urcrnrlat=-33,
llcrnrlon=139.0,urcrnrlon=151.0,lat_ts=0,resolution='i')
 x,y=map(*N.meshgrid(LON,LAT))
 u=-1*N.sin(WDIR*N.pi/180)# added negative to account for
southern hemisphere
 v=-1*N.cos(WDIR*N.pi/180)
 map.quiver(x,y,u, v)
On Wed, Oct 5, 2011 at 3:20 PM, questions anon <que...@gm...>wrote:
> thank you! of course!
>
>
> On Wed, Oct 5, 2011 at 3:08 PM, Eric Firing <ef...@ha...> wrote:
>
>> On 10/04/2011 05:40 PM, questions anon wrote:
>> > Excellent, thank you. That works for both quiver and barb.
>> > In regards to the shape that has to do with the netcdf file, wind
>> > direction variable also has lat and lon. I ended up needing to slice so
>> > I could skip a few points otherwise there was too many arrows on the
>> map.
>> > Below is the code that worked in case someone else needs help.
>>
>> Are you sure it worked correctly? I don't think so. See below.
>>
>> > Thanks again
>> >
>> > from netCDF4 import Dataset
>> > import numpy as N
>> > import pylab as plt
>> > from numpy import ma as MA
>> > from mpl_toolkits.basemap import Basemap
>> > import os
>> >
>> > ncfile=Dataset('E:/temp_winddir/IDZ00026_VIC_ADFD_Wind_Dir_SFC.nc',
>> > 'r+', 'NETCDF4')
>> > WDIR=ncfile.variables['Wind_Dir_SFC'][20,0::5,0::5]
>>
>> Don't you need to convert from degrees to radians? sin and cos (used
>> below) expect radians, not degrees. You can use N.deg2rad(WDIR) to
>> convert.
>>
>> > LAT=ncfile.variables['latitude'][0::5]
>> > LON=ncfile.variables['longitude'][0::5]
>> > TIME=ncfile.variables['time'][20]
>> > ncfile.close()
>> >
>> > map = Basemap(projection='merc',llcrnrlat=-40,urcrnrlat=-33,
>> > llcrnrlon=139.0,urcrnrlon=151.0,lat_ts=0,resolution='i')
>> > x,y=map(*N.meshgrid(LON,LAT))
>> > u=1*N.sin(WDIR)
>> > v=1*N.cos(WDIR)
>> > map.quiver(x,y,u, v)
>>
>> Assuming you do convert to radians the above will work for your mercator
>> projection but it will not align the vectors correctly with respect to
>> the parallels and meridians for other projections, so you should use
>> map.rotate_vector as in the basemap quiver demo.
>>
>> Eric
>>
>>
>> >
>> > # otherwise use the barb tool - map.barbs(x,y,u, v)
>> >
>> > plt.title('Wind Direction')
>> > plt.show()
>>
>>
>> ------------------------------------------------------------------------------
>> All the data continuously generated in your IT infrastructure contains a
>> definitive record of customers, application performance, security
>> threats, fraudulent activity and more. Splunk takes this data and makes
>> sense of it. Business sense. IT sense. Common sense.
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>> _______________________________________________
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>>
>
>

On 10/13/2011 09:50 AM, Durrieu Jean-Louis wrote:
> Hi Eric, Fernando,
>
> thanks for your answers!
>
> On Oct 13, 2011, at 8:47 PM, Eric Firing wrote:
>
>> On 10/12/2011 10:47 PM, Durrieu Jean-Louis wrote:
>>
>> There is no compiled qt4 code, so installation should not require
>> pyqt4--and I don't think it does. What led to your conclusion that
>> you needed it to install from source?
>>
>
> It s just that when I type "python setup.py build/--help/install",
> depending on whether pyqt4 is installed or not, the script detects
> that Qt is present or not (respectively), and pyside does not change
> that behaviour. I must admit I did not try to run my script even when
> Qt was not detected, maybe it works... But I guess there is a
> consequence to the detection of Qt at the build step?
>
> Sorry for not providing the exact output of the build step, I m on
> another computer. On my mac, the section of interest is: OPTIONAL
> BACKEND DEPENDENCIES libpng: 1.5.2 Tkinter: Tkinter: version not
> identified, Tk: 8.5, Tcl: 8.5 Gtk+: no * Building for Gtk+ requires
> pygtk; you must be able * to "import gtk" in your build/install
> environment Mac OS X native: yes Qt: no Qt4: Qt: 4.7.3, PyQt4: 4.8.5
> Cairo: no
>
> Here, it detected my pyqt4. But when it s not there, even if pyside
> is installed, I get a "Qt4: no" instead... Do you mean that it's
> still going to work, even it was not detected there?
Yes, it should work fine; as far as I know, nothing depends on the 
outcome of that auto-detection for qt4. The pyside support is always 
included in backend_qt4.py and backend_qt4agg.py, which are pure python, 
and are present regardless of whether pyqt4 itself is detected.
Eric
>
>> This does not make sense to me. Assuming you are using bash, put
>> this in your .bashrc file:
>>
>> export QT_API=pyside
>>
>> Anything you execute in a terminal window opened after that change
>> should find the new environment variable.
>>
>
> Oh, sorry for that! I must have been confused, I think I only typed
> "QT_API=pyside" at the prompt, so I guess without the "export"
> (doh!), that was useless... Since the doc (somewhere) talked about
> "ETS environment variables", I thought there was something else to
> it. If not, then I ll have to learn my bash again :-)
>
> Not a big issue, anyway!
>
> Cheers!
>
> Jean-Louis
> ------------------------------------------------------------------------------
>
>
All the data continuously generated in your IT infrastructure contains a
> definitive record of customers, application performance, security
> threats, fraudulent activity and more. Splunk takes this data and
> makes sense of it. Business sense. IT sense. Common sense.
> http://p.sf.net/sfu/splunk-d2d-oct
> _______________________________________________ Matplotlib-users
> mailing list Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

Hi Eric, Fernando,
thanks for your answers!
On Oct 13, 2011, at 8:47 PM, Eric Firing wrote:
> On 10/12/2011 10:47 PM, Durrieu Jean-Louis wrote:
> 
> There is no compiled qt4 code, so installation should not require 
> pyqt4--and I don't think it does. What led to your conclusion that you 
> needed it to install from source?
> 
It s just that when I type "python setup.py build/--help/install", depending on whether pyqt4 is installed or not, the script detects that Qt is present or not (respectively), and pyside does not change that behaviour. I must admit I did not try to run my script even when Qt was not detected, maybe it works... But I guess there is a consequence to the detection of Qt at the build step?
Sorry for not providing the exact output of the build step, I m on another computer. On my mac, the section of interest is:
OPTIONAL BACKEND DEPENDENCIES
 libpng: 1.5.2
 Tkinter: Tkinter: version not identified, Tk: 8.5, Tcl: 8.5
 Gtk+: no
 * Building for Gtk+ requires pygtk; you must be able
 * to "import gtk" in your build/install environment
 Mac OS X native: yes
 Qt: no
 Qt4: Qt: 4.7.3, PyQt4: 4.8.5
 Cairo: no
Here, it detected my pyqt4. But when it s not there, even if pyside is installed, I get a "Qt4: no" instead... Do you mean that it's still going to work, even it was not detected there?
> This does not make sense to me. Assuming you are using bash, put this 
> in your .bashrc file:
> 
> export QT_API=pyside
> 
> Anything you execute in a terminal window opened after that change 
> should find the new environment variable.
> 
Oh, sorry for that! I must have been confused, I think I only typed "QT_API=pyside" at the prompt, so I guess without the "export" (doh!), that was useless... Since the doc (somewhere) talked about "ETS environment variables", I thought there was something else to it. If not, then I ll have to learn my bash again :-)
Not a big issue, anyway!
Cheers! 
Jean-Louis

On 10/12/2011 10:47 PM, Durrieu Jean-Louis wrote:
> Dear all, matplotlib users and devs,
>
> I have been trying the latest announced version of Matplotlib
> (1.1.0). The new feature that attracted me is the PySide support.
>
> However, I tried to install it under Ubuntu 11.04, but I needed pyqt4
> installed in order to install it from source. Is there a way to
> install it with only pyside installed?
There is no compiled qt4 code, so installation should not require 
pyqt4--and I don't think it does. What led to your conclusion that you 
needed it to install from source?
In any case, I opened
https://github.com/matplotlib/matplotlib/issues/521 for this.
>
> Once installed, I could uninstall pyqt4, and run my python scripts,
> with replacing pyqt4 by pyside. However, I am not sure what the "ETS
> environment variable" is (yes, it s related to the enthought tool
> suite, but what if I do not want it - for now), and I had to set the
> QT_API variable on the command line call to python: setting it as a
> "normal" environment variable does not work. So, to be able to use
> "only" pyside, I need to do:
>
> QT_API=pyside python myscript.py
>
> Is that the right way to do so? Is there any way of setting the
> QT_API more "definitely", and not having to change the call to
> python?
This does not make sense to me. Assuming you are using bash, put this 
in your .bashrc file:
export QT_API=pyside
Anything you execute in a terminal window opened after that change 
should find the new environment variable.
Eric
>
> So far, my program (I really have only one at the moment) seems to
> work well, using QtCore, QtGui and phonon, except for phonon, where
> it seems that "seeking" in a file does not really work under
> Ubuntu... if anyone has an idea (I know, not the right mailing list,
> but just in case).
>
> At last, probably a question that will solve all the above ones: when
> is the new Matplotlib version going to be included in EPD? That's, by
> the way, mainly the reason why I consider using PySide instead of
> PyQt4.
>
> Thanks for reading!
>
> Cheers,
>
> Jean-Louis

Hi Jean-Louis,
On Thu, Oct 13, 2011 at 1:47 AM, Durrieu Jean-Louis
<jea...@ep...> wrote:
>
> Is that the right way to do so? Is there any way of setting the QT_API more "definitely", and not having to change the call to python?
>
Yes, in your $HOME/.bashrc file that your shell loads at startup time,
you can write
export QT_API="pyside"
And this will ensure that you always have this variable set as part of
your 'environment'. The concept of 'environment' is a unix-specific
idea of a set of variables and other parameters visible to any
program; you can actually read and write the enviroment in python by
importing 'os' and using the os.environ variable:
$ export SOMEVAR="Hello matplotlib"
$ ipython --no-banner
In [1]: import os
In [2]: os.environ['SOMEVAR']
Out[2]: 'Hello matplotlib'
Cheers,
f

I use matplotlib 1.1 and numpy 1.5.0
gc.collect() after the function call solved the problem! Thanks alot!
Den torsdagen den 13:e oktober 2011 skrev John Hunter<jd...@gm...>:
> On Thu, Oct 13, 2011 at 12:42 AM, Viktor Forsman
> <vik...@gm...> wrote:
>> Hi,
>>
>> I have problems with a memory leak in a webapplication involving
matplotlib.
>> Basically, I have a function which usies the OO way of generating the
graph,
>> printing it to a StringIO object and returning that. I've posted a
question
>> with the details on stackoverflow
>> (
http://stackoverflow.com/questions/7740832/need-help-identifying-a-memory-leak-involving-matplotlib-and-flask
).
>> Any ideas are highly appreciated.
>
> What version of matplotlib and numpy are you using? Does it help to do:
>
> import gc
> gc.collect()
>
> after a call to plot total or plot month?
>
> Also, you appear to be adding data to "plot_values" and storing this
> on every call. Are you sure the leak is in mpl and not here?
> JDH
>

Hi,
Not directly answering your questions but the code below produces what you
are trying to achieve:
import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid.parasite_axes import SubplotHost
plt.close('all')
fig1 = plt.figure(figsize=(11, 8.5))
ax1 = SubplotHost(fig1, 111)
fig1.add_subplot(ax1)
## define data
x = np.arange(1,11)
y = np.random.random(len(x))
# First X-axis
ax1.plot(x, y)
xmin, xmax = ax1.xaxis.get_view_interval()
ax1.xaxis.set_label_text("First X-axis")
ax1.yaxis.set_label_text("Sample data")
# Second X-axis
parx = ax1.twiny()
offset = 0, -60
new_axisline = parx.get_grid_helper().new_fixed_axis
parx.axis["bottom"] = new_axisline(loc="bottom", axes=parx, offset=offset)
parx.axis["bottom"].label.set_text("Second X-axis")
line1, = parx.plot((1./x), np.ones(len(x)))
line1.set_visible(0)
parx.set_xlim(xmin=xmax,xmax=xmin)
parx.axis["top"].set_visible(False)
ax1.grid(1)
plt.tight_layout()
plt.show()
A few notes:
1-) axes is plural for axis. I always get confused with these words. Tricky
English :)
2-) This code uses the older AxisGrid toolkit functions, and not super
efficient since it makes an empty plot call with a different x-units.
However, using the same ideas and with some dedication you can create
multi-axes like the one shown here -
http://imageshack.us/photo/my-images/820/plot1r.png/
I had tried the newer AxisGrid approach as JJ suggested but I failed making
the plot look pretty. Plus sometimes using the AffineTransforms are not very
practical.
3-) I said "empty plot call" but it is actually where you convert your unit.
(np.ones call is another dummy call since the line is made invisible after
its call) To me it is more explicit than converting units via transforms. In
this example I just assume x as wavelength and convert it to wavenumber with
1/x. You need to adjust that call according to your unit conversion as well
as adjusting the limits of your newly scaled unit.
As usual JJ can give a more elegant solution for your question, but
sometimes practicality beats purity and you engineer your own solution.
On Wed, Oct 12, 2011 at 11:36 PM, List Comprehension <
lis...@gm...> wrote:
>
> Hello, I am interested in plotting two (x) axes for the same figure (one of
> is just showing linearly transformed values of the other); one of them
> offset from the plot if possible. For instance, I have the following code:
>
> import numpy as np
> import matplotlib.pyplot as plt
> import mpl_toolkits.axisartist as AA
>
> ## define data
> x = np.array(range(11))
> xlab = x*2
> y = np.random.random(len(x))
>
> fig = plt.figure()
> ## first axes which is only for drawing the axis
> axsecond = AA.Subplot(fig, 1,1,1)
> fig.add_subplot(axsecond)
> axsecond.set_xlim([min(xlab),max(xlab)])
> axsecond.set_xticks(np.linspace(min(xlab),max(xlab),5))
> axsecond.axis["bottom", "top", "left", "right"].set_visible(False)
> axsecond.axis["newx"] = axsecond.new_floating_axis(nth_coord=0, value=1)
> axsecond.axis["newx"].set_axis_direction("top")
> axsecond.set_clip_on(False)
> axsecond.axis["newx"].toggle(all=True)
> axsecond.axis["newx"].set_visible(True)
> plt.draw()
> ## the main set of axes containing the data
> axmain = fig.add_subplot(1,1,1)
> plt.plot(x,y)
>
>
> In this example I wonder
>
> 1) How to turn off the top axis of axmain so the ticks from axsecond are
> visible? Something like axmain["top"].set_visible(False) (which does not
> work of course).
>
> 2) If I wanted to include an offset (below the main axis), I feel like
> something like the following should work but doesn't:
>
> ax.axis["newx"] = ax.new_floating_axis(nth_coord=0, value=-0.2) ## outside
> of (0,1)
> ax.axis["newx"].set_axis_direction("bottom")
> ax.set_clip_on(False)
>
> Thanks in advance!
>
-- 
Gökhan

On Thursday, October 13, 2011, Neal Becker <ndb...@gm...> wrote:
> Using interactively (via emacs/ipython), on closing a plot window I see:
>
> X Error: BadWindow (invalid Window parameter) 3
> Major opcode: 20 (X_GetProperty)
> Resource id: 0x5802e1b
>
>
Which backend/platform?
Ben Root

linux fedora 15 x86_64
backend : Qt4Agg
Now it's gone away, after killing the *Python* buffer and restarting the python 
process. If it comes back I'll try to get more info.
John Hunter wrote:
> On Thu, Oct 13, 2011 at 8:03 AM, Neal Becker
> <ndb...@gm...> wrote:
>> Using interactively (via emacs/ipython), on closing a plot window I see:
>>
>> X Error: BadWindow (invalid Window parameter) 3
>> Major opcode: 20 (X_GetProperty)
>> Resource id: 0x5802e1b
> 
> Could you give us some more information.
> 
> What operating system?
> 
> Which matplotlib backend and GUI version?
> 
> What version of ipython?
> 
> What, exactly do you do to reproduce the problem?
> 
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On Thu, Oct 13, 2011 at 8:03 AM, Neal Becker <ndb...@gm...> wrote:
> Using interactively (via emacs/ipython), on closing a plot window I see:
>
> X Error: BadWindow (invalid Window parameter) 3
> Major opcode: 20 (X_GetProperty)
> Resource id: 0x5802e1b
Could you give us some more information.
What operating system?
Which matplotlib backend and GUI version?
What version of ipython?
What, exactly do you do to reproduce the problem?

Using interactively (via emacs/ipython), on closing a plot window I see:
 X Error: BadWindow (invalid Window parameter) 3
 Major opcode: 20 (X_GetProperty)
 Resource id: 0x5802e1b