matplotlib-users Mailing List for matplotlib

I finally got the thing to compile.  What I had to do was long and
involved.  I'll write it up and slap it on the wiki when I am confident I
know what's going on.  For the moment, however, even though it compiles, I
still don't think I know what's going on.  I get the following messages
and terminating error when I try to import pylab from the python
interpreter.  Any suggestions about where to start looking, and what to
look for, to debug this will be greatly appreciated.

Thanks!

E


$ python
Python 2.4.2 (#1, Oct  3 2005, 14:10:19)
[GCC 3.4.4] on sunos5
Type "help", "copyright", "credits" or "license" for more information.
>>> import pylab
LazyValue::init_type
Value::init_type
BinOp::init_type
Point::init_type
Interval::init_type
Bbox::init_type
Func::init_type
FuncXY::init_type
Transformation::init_type
SeparableTransformation::init_type
NonseparableTransformation::init_type
Affine::init_type
init_nc_transforms
Glyph::init_type
FT2Font::init_type
_transforms_module::new_value
_transforms_module::new_value
_transforms_module::new_point
Point::Point
_transforms_module::new_value
_transforms_module::new_value
_transforms_module::new_point
Point::Point
_transforms_module::new_bbox
Bbox::Bbox
_transforms_module::new_value
_transforms_module::new_value
_transforms_module::new_point
Point::Point
_transforms_module::new_value
_transforms_module::new_value
_transforms_module::new_point
Point::Point
_transforms_module::new_bbox
Bbox::Bbox
_transforms_module::new_func
_transforms_module::new_func
_transforms_module::new_separable_transformation
BBoxTransformation::BBoxTransformation
SeparableTransformation::SeparableTransformation
init_nc_image
Image::init_type
_transforms_module::new_value
Value::~Value
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/home/erik/util/lib/python2.4/site-packages/pylab.py", line 1, in
?
    from matplotlib.pylab import *
  File "/home/erik/util/lib/python2.4/site-packages/matplotlib/pylab.py",
line 217, in ?
    new_figure_manager, draw_if_interactive, show = pylab_setup()
  File
"/home/erik/util/lib/python2.4/site-packages/matplotlib/backends/__init__.py",
line 24, in pylab_setup
    globals(),locals(),[backend_name])
  File
"/home/erik/util/lib/python2.4/site-packages/matplotlib/backends/backend_gtkagg.py",
line 9, in ?
    from backend_agg import FigureCanvasAgg
  File
"/home/erik/util/lib/python2.4/site-packages/matplotlib/backends/backend_agg.py",
line 94, in ?
    from _nc_backend_agg import RendererAgg as _RendererAgg
ImportError: No module named _nc_backend_agg

>>>>> "Erik" == Erik Curiel <ec...@ke...> writes:

    Erik> Hi, my name is Erik, and I have a compiling problem.  I hope
    Erik> to get it resolved in fewer than 12 steps.

Hi Erik -- if you succeed, then we'll have convincing proof that
compiling mpl on solaris is easier than giving up the sauce.

    Erik> In particular, I'm the Erik Curiel, referred to in this
    Erik> posting from a few months ago by John Hunter, who had (and
    Erik> still has) problems compiling mpb on solaris 10:

    Erik> http://sourceforge.net/mailarchive/message.php?msg_id=12122609

Remind me whether you are using the solaris compiler or gcc.  As far
as I know, people have had more luck with gcc so if this is an option
for you, please use it.  Skip Montanaro recently got mpl working on
Solaris with a few hacks to the distutils setup, and Nadia has as
well.

Have you googled this error message (I assume you are still getting
this one)?

  "error: `::btowc" has not been declared"

Some posts suggest that it is a bug in the solaris C++ implementation.
Also, did you follow the advice in the paragraphs you linked to,
specifically

   Fourth from the top and was
   http://lists.schmorp.de/pipermail/rxvt-unicode/2005q2/000092.html .
   This thread is not related to matplotlib, and first response there
   isn"t too helpful, but if you follow the rest of the thread you"ll
   get lots of good information.  In particular, this response
   (including all the posts in the thread) looks helpful
   http://lists.schmorp.de/pipermail/rxvt-unicode/2005q2/000104.html

If so, do you have anything to report from these attempts?

    Erik> Although I've asked John multiple times to forward me the
    Erik> information from Mike Rightmire and Thomas Wessell, who, it

So many questions, so little time.  And a ring to hold to boot.
You'll have to forgive me.

JDH

I installed the fink version of mpl on my 10.3.9 laptop the other day.  I've
not been able to work around font problems and am looking for suggestions.
When I run "ipython -pylab" (GTKAgg backend) I get this traceback:

      File "/sw/bin/ipython", line 28, in ?
        IPython.Shell.start().mainloop()
      File "/sw/lib/python2.3/site-packages/IPython/Shell.py", line 883, in start
        return shell()
      File "/sw/lib/python2.3/site-packages/IPython/Shell.py", line 810, in __init__
        IPShellGTK.__init__(self,argv,user_ns,debug,shell_class=MatplotlibMTShell)
      File "/sw/lib/python2.3/site-packages/IPython/Shell.py", line 618, in __init__
        on_kill=[mainquit])
      File "/sw/lib/python2.3/site-packages/IPython/ipmaker.py", line 85, in make_IPython
        IP = shell_class('__IP',user_ns=user_ns,**kw)
      File "/sw/lib/python2.3/site-packages/IPython/Shell.py", line 500, in __init__
        user_ns,b2 = self._matplotlib_config(name)
      File "/sw/lib/python2.3/site-packages/IPython/Shell.py", line 373, in _matplotlib_config
        from matplotlib import backends
      File "/sw/lib/python2.3/site-packages/matplotlib/backends/__init__.py", line 56, in ?
        new_figure_manager, draw_if_interactive, show = pylab_setup()
      File "/sw/lib/python2.3/site-packages/matplotlib/backends/__init__.py", line 24, in pylab_setup
        globals(),locals(),[backend_name])
      File "/sw/lib/python2.3/site-packages/matplotlib/backends/backend_gtkagg.py", line 8, in ?
        from matplotlib.figure import Figure
      File "/sw/lib/python2.3/site-packages/matplotlib/figure.py", line 3, in ?
        from axes import Axes, Subplot, PolarSubplot, PolarAxes
      File "/sw/lib/python2.3/site-packages/matplotlib/axes.py", line 14, in ?
        from axis import XAxis, YAxis
      File "/sw/lib/python2.3/site-packages/matplotlib/axis.py", line 25, in ?
        from font_manager import FontProperties
      File "/sw/lib/python2.3/site-packages/matplotlib/font_manager.py", line 993, in ?
        fontManager = FontManager()
      File "/sw/lib/python2.3/site-packages/matplotlib/font_manager.py", line 837, in __init__
        rebuild()
      File "/sw/lib/python2.3/site-packages/matplotlib/font_manager.py", line 830, in rebuild
        self.ttfdict = createFontDict(self.ttffiles)
      File "/sw/lib/python2.3/site-packages/matplotlib/font_manager.py", line 456, in createFontDict
        font = ft2font.FT2Font(str(fpath))
    RuntimeError: Could not load facefile /Library/Fonts/CharcoalCY.dfont; Unknown_File_Format

I went looking for a solution and found this page:

    http://www.soe.ucsc.edu/~you/notes/matplotlib-fink-install.html

It suggested copying ttf files from Windows, setting TTFPATH and removing
~/.ttfont.cache.  Not having Windows, I poked around some more and found
fondu:

    http://fondu.sourceforge.net/

I downloaded and built that, then converted all the fonts in /Library/Fonts,
set TTFPATH and removed ~/.ttfont.cache.  No change.  Any ideas?

Thx,

-- 
Skip Montanaro
Katrina Benefit Concerts: http://www.musi-cal.com/katrina
sk...@po...

John,

There may be a couple of related questions:

1) For how long do we maintain compatibility with older versions of 
Numeric and numarray?  Even if the array interface has been added, or is 
being added, to numarray, it won't be present in older versions or on 
classic Numeric.

2) Even if the array interface is the way to go for the future, it may 
be easier for now to let cntr.c continue to use the Numeric C API, which 
I think is maintained intact in scipy.  In fact, doing it this way looks 
very easy indeed.

It may be that I am misunderstanding something fundamental about how the 
array interface works and is implemented; I haven't looked at it closely.

Eric

John Hunter wrote:
>>>>>>"Eric" == Eric Firing <ef...@ha...> writes:
> 
> 
>     Eric> To use scipy as a complete replacement for Numeric or
>     Eric> numarray will require work in numerix, in the setup.py build
>     Eric> system, and possibly in cntr.c, which needs to build
>     Eric> separate versions for numarray and Numeric. (I expect little
>     Eric> or no change will actually be needed in cntr.c.)
> 
> I talked to Travis about this at scipy and he said that with the new
> array interface, we wouldn't need to compile separate extensions for
> each of Numeric, numarray and scipy (as we do now, eg with
> _nc_transforms, _na_transforms, etc).  This is good news because it
> implies shorter compile times and smaller binary distributions, but I
> can't quite understand how this would work yet, eg, to support the
> there packages with one binary *.so).  But this may be some of the
> black magic of the new array interface.  If correct, this approach
> would require *either* Numeric 24, numarray (something recent) or
> scipy_base.
> 
> Perhaps Todd has further insight, as the author of numerix and
> presumably the implementor of the array interface for numarray...
> 
> JDH

Hi, my name is Erik, and I have a compiling problem.  I hope to get it
resolved in fewer than 12 steps.

In particular, I'm the Erik Curiel, referred to in this posting from a few
months ago by John Hunter, who had (and still has) problems compiling mpb
on solaris 10:

http://sourceforge.net/mailarchive/message.php?msg_id=12122609

Although I've asked John multiple times to forward me the information from
Mike Rightmire and Thomas Wessell, who, it would seem, managed to get mpb
to compile on solaris 10 after much effort, he persists in blowing me off
(and this even though he is to be the best man at my wedding in March).  I
am hoping that I can extract this information from him by applying the
lever of public shame.  

If John cannot be so easily shamed, would Mike or Thomas please email me
the information?  I'll be happy to take responsibility for posting it
somewhere publicly accessible (e.g., the mpb wiki), so poor suckers such
as myself won't have to resort, in the future, to attempting to shame John
in to getting off his ass and disseminating the information.

Thanks!

Erik

Eric Firing wrote:

> No, [new scipy core] *does* include masked arrays.

Someone should tell Paul Dubois then :-) . See the bottom of this thread:

http://sourceforge.net/mailarchive/forum.php?thread_id=8355108&forum_id=4890

>>>>> "Eric" == Eric Firing <ef...@ha...> writes:

    Eric> To use scipy as a complete replacement for Numeric or
    Eric> numarray will require work in numerix, in the setup.py build
    Eric> system, and possibly in cntr.c, which needs to build
    Eric> separate versions for numarray and Numeric. (I expect little
    Eric> or no change will actually be needed in cntr.c.)

I talked to Travis about this at scipy and he said that with the new
array interface, we wouldn't need to compile separate extensions for
each of Numeric, numarray and scipy (as we do now, eg with
_nc_transforms, _na_transforms, etc).  This is good news because it
implies shorter compile times and smaller binary distributions, but I
can't quite understand how this would work yet, eg, to support the
there packages with one binary *.so).  But this may be some of the
black magic of the new array interface.  If correct, this approach
would require *either* Numeric 24, numarray (something recent) or
scipy_base.

Perhaps Todd has further insight, as the author of numerix and
presumably the implementor of the array interface for numarray...

JDH

> Chris Fonnesbeck wrote:
> 
>> I think there is more to it than that. There are all sorts of
>> dependencies on either Numeric or numarray that need to be addressed.
>> Try installing matplotlib without either Numeric or numarray -- I dont
>> think you will get very far.
>>  
>>
> Ah, good point.  It would be good to begin work on this, but IMHO the 
> new scipy_core has a bit to go before it is ready for prime time.  
> Someone just pointed out on the numpy list, for example, that it 
> presently does not include masked arrays, a capability I use often and 
> support for which was painstakingly added to Matplotlib over the last 
> year or so.
> 

No, it *does* include masked arrays.  Try:

import scipy.base.ma as ma

To use scipy as a complete replacement for Numeric or numarray will 
require work in numerix, in the setup.py build system, and possibly in 
cntr.c, which needs to build separate versions for numarray and Numeric. 
  (I expect little or no change will actually be needed in cntr.c.)

I haven't figured out yet exactly what is present and what is missing 
relative to old Numeric, and the things that numerix imports, so I am 
not sure whether scipy_core has everything needed for a one-to-one 
substitution; it looks like it is close, at least.

Eric

Sascha wrote:
> Try changing the resolution to a value of 300 or 600 dpi. This should
> give you very high quality figures when using the Agg backend. The
> standard is 80 which is ok for screen display but for printing
> purposes you should use a higher value. See
> http://matplotlib.sourceforge.net/matplotlib.pylab.html#-figure (dpi
> keyword argument).

Except that savefig() overrides the Figure dpi, so you need to pass the 
desired dpi in to the savefig function (or method):

savefig(filename, dpi=300)

-Chris

-- 
Christopher Barker, Ph.D.
Oceanographer
                                     		
NOAA/OR&R/HAZMAT         (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception

Chr...@no...

Vedpathak, Rameshwari IN BLR SISL wrote:
> Hello,
>  
> As mentioned in the
> site(http://matplotlib.sourceforge.net/matplotlib.pylab.html#-savefig)
> dpi is the resolution in dots per inch.
> When we change dpi the size of the figure gets changed. But we want the
> resolution to be changed and not the figure size.
>  
> Can anyone give more information on 'dpi' parameter.

READ THIS MAILING LIST! AND THE WIKI!

There was just a discussion about this on this list last week, which 
resulted in this post to the Wiki:

http://www.scipy.org/wikis/topical_software/AdjustingImageSize

Please feel free to improve that Wiki page, or if something is unclear, 
or doesn't work, post a question here about it.

-Chris

-- 
Christopher Barker, Ph.D.
Oceanographer
                                     		
NOAA/OR&R/HAZMAT         (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception

Chr...@no...

Chris Fonnesbeck wrote:

>I think there is more to it than that. There are all sorts of
>dependencies on either Numeric or numarray that need to be addressed.
>Try installing matplotlib without either Numeric or numarray -- I dont
>think you will get very far.
>  
>
Ah, good point.  It would be good to begin work on this, but IMHO the 
new scipy_core has a bit to go before it is ready for prime time.  
Someone just pointed out on the numpy list, for example, that it 
presently does not include masked arrays, a capability I use often and 
support for which was painstakingly added to Matplotlib over the last 
year or so.

Rameshwari,
I think everyone else has given you enough pointers on increasing the 
resolution of your plots, I just thought I'd chime in w/ more info on JPEG.

JPEG is lossy compression format - it throws away information.  PNG is a 
loss-less compression format - it does not throw away information.  Since 
both formats start from the same raster image, you cannot increase your 
picture quality by changing formats, only by changing the original 
raster.  In particular, JPEG is a terrible format for plots.  It was 
designed to compress pictures and it cannot deal well with rapid changes in 
color in a image (like a black line on a white background).

Most JPEG compressed plots will show artifacts around all of the lines so 
instead of seeing the pixels (for a black line on a white background) like 
this:

         white, white, white, black, white, white, white

In a JPEG image, you would see:

         white, grey, grey, black, grey, grey, white

As others have already indicates, you can increase your DPI through various 
means or switch to PS (which uses vector based drawing commands instead of 
a set of pixels).

Ted

At 05:38 AM 10/3/2005, Vedpathak, Rameshwari  IN BLR SISL wrote:
>Hello,
>
>We are using matplotlib version 0.8 (matplotlib-0.80.win32-py2.2.exe).
>
>The plots are saved as .png, but we feel the quality of this picture is 
>not so good. (not good resolution supported).
>Is there anyway by which we can improve the picture quality? Say like by 
>using .jpeg.
>
>We tried to save the plot as .jpeg as mentioned on the site 
>(<http://matplotlib.sourceforge.net/matplotlib.pylab.html#-savefig>http://matplotlib.sourceforge.net/matplotlib.pylab.html#-savefig) 
>, but we get error "IOError: Do not know know to handle extension *.jpeg...."
>Does it mean that matplotlib 0.8 does not support jpeg format?
>
>If anyone has an idea about this then please do let us know.
>
>Thanks in advance
>
>Best Regards,
>Rameshwari

Ted Drain     Jet Propulsion Laboratory   ted...@jp...    

Hi there,

I have some data whose x values supposed to be centered around 0. So I'd like 
to position the y-axis at x=0, but centered in the plot (e.g. -1<=x<=1).

I'm a matplotlib newbie (from what I've seen so far it rocks btw), but as it 
stands it seems impossible to do this with the axes() command. On the goals 
page I came across "Detachable axis from main axes box and customizable 
tickline locations" which seems to aim for functionality which could do this.

So, my question is: Can I center my y-axis in current versions of matplotlib 
(am currently using 0.80-r1 on gentoo) and if so, how? If not, what's the 
implementation status of this new feature?

Thanks.

-- 
Kilian Hagemann

Climate Systems Analysis Group
University of Cape Town
Republic of South Africa
Tel(w): ++27 21 650 2748

Hi there,

I have some data whose x values supposed to be centered around 0. So I'd like 
to position the y-axis at x=0, but centered in the plot (e.g. -1<=x<=1).

I'm a matplotlib newbie (from what I've seen so far it rocks btw), but as it 
stands it seems impossible to do this with the axes() command. On the goals 
page I came across "Detachable axis from main axes box and customizable 
tickline locations" which seems to aim for functionality which could do this.

So, my question is: Can I center my y-axis in current versions of matplotlib 
(am currently using 0.80-r1 on gentoo) and if so, how? If not, what's the 
implementation status of this new feature?

Thanks.

-- 
Kilian Hagemann
5 Myburgh Close
Ruyteplaats Estate
7806 Hout Bay

Tel(w): (021) 650 2748
Tel(m): 082 768 9830
Tel(h): (021) 685 7206

Try changing the resolution to a value of 300 or 600 dpi. This should =
give you very high quality figures when using the Agg backend. The =
standard is 80 which is ok for screen display but for printing purposes =
you should use a higher value. See =
http://matplotlib.sourceforge.net/matplotlib.pylab.html#-figure (dpi =
keyword argument).

  ----- Original Message -----=20
  From: Vedpathak, Rameshwari IN BLR SISL=20
  To: mat...@li...=20
  Sent: Monday, October 03, 2005 2:38 PM
  Subject: [Matplotlib-users] picture quality of the figures


  Hello,

  We are using matplotlib version 0.8 (matplotlib-0.80.win32-py2.2.exe).

  The plots are saved as .png, but we feel the quality of this picture =
is not so good. (not good resolution supported).
  Is there anyway by which we can improve the picture quality? Say like =
by using .jpeg.=20

  We tried to save the plot as .jpeg as mentioned on the site =
(http://matplotlib.sourceforge.net/matplotlib.pylab.html#-savefig)  , =
but we get error "IOError: Do not know know to handle extension =
*.jpeg...."
  Does it mean that matplotlib 0.8 does not support jpeg format?

  If anyone has an idea about this then please do let us know.

  Thanks in advance

  Best Regards,
  Rameshwari

>>>>> "Vedpathak," == Vedpathak, Rameshwari IN BLR SISL <Ram...@si...> writes:

    Vedpathak> Hello, As mentioned in the
    Vedpathak> site(http://matplotlib.sourceforge.net/matplotlib.pylab.html#-savefig)
    Vedpathak> dpi is the resolution in dots per inch.  When we
    Vedpathak> change dpi the size of the figure gets changed. But we
    Vedpathak> want the resolution to be changed and not the figure
    Vedpathak> size.
 
    Vedpathak> Can anyone give more information on 'dpi' parameter.
 
The figure size in pixels is width*dpi by height*dpi.  png is a raster
format which means it stores the information in a pixel buffer.  You
cannot get higher resolution without changing the figure size in
pixels.  If you want a higher resolution picture, set the dpi to a
higher number.

Alternatively, as others have suggested, use a vector output like PS
or SVG.

JPEG will not give you a better picture quality -- usually it will be
worse for lines and such.

JDH

 

> We are using matplotlib version 0.8 (matplotlib-0.80.win32-py2.2.exe).
>
> The plots are saved as .png, but we feel the quality of this picture is
> not so good. (not good resolution supported).
> Is there anyway by which we can improve the picture quality? Say like by
> using .jpeg.

  Jpeg is will not be better- it is also a compressed format.

  A better quality can be obtained with postscript (*.ps) or encapsulated=20
postscript (*.eps)

> We tried to save the plot as .jpeg as mentioned on the site
> (http://matplotlib.sourceforge.net/matplotlib.pylab.html#-savefig)  ,
> but we get error "IOError: Do not know know to handle extension
> *.jpeg...."
> Does it mean that matplotlib 0.8 does not support jpeg format?

   Try with .jpg, not .jpeg

	Vincent
=2D-=20
Vincent Favre-Nicolin
Universit=E9 Joseph Fourier
http://v.favrenicolin.free.fr
ObjCryst & Fox : http://objcryst.sourceforge.net

Hello,
=20
As mentioned in the
site(http://matplotlib.sourceforge.net/matplotlib.pylab.html#-savefig)
dpi is the resolution in dots per inch.
When we change dpi the size of the figure gets changed. But we want the
resolution to be changed and not the figure size.
=20
Can anyone give more information on 'dpi' parameter.
=20
Thanks in advance
=20
Best Regards,
Rameshwari
=20

=20

Hello,
=20
We are using matplotlib version 0.8 (matplotlib-0.80.win32-py2.2.exe).
=20
The plots are saved as .png, but we feel the quality of this picture is
not so good. (not good resolution supported).
Is there anyway by which we can improve the picture quality? Say like by
using .jpeg.=20
=20
We tried to save the plot as .jpeg as mentioned on the site
(http://matplotlib.sourceforge.net/matplotlib.pylab.html#-savefig)  ,
but we get error "IOError: Do not know know to handle extension
*.jpeg...."
Does it mean that matplotlib 0.8 does not support jpeg format?
=20
If anyone has an idea about this then please do let us know.
=20
Thanks in advance
=20
Best Regards,
Rameshwari

> Date: Sat, 01 Oct 2005 18:11:00 -0700
> From: Stephen Walton <ste...@cs...>
> CC: mat...@li...
> Subject: Re: [Matplotlib-users] matplotlib and scipy_core
>
> Chris Fonnesbeck wrote:
>
> >Any idea how easy it will be to use matplotlib with scipy_core?
> >
> At the moment it looks trivial.  I have matplotlib 0.84 and "new scipy"
> installed and did:
>
> ipython -pylab
> import scipy as S
> x=3DS.arange(10)
> plot(x,x**2)
>
> and got a plot.
>

I think there is more to it than that. There are all sorts of
dependencies on either Numeric or numarray that need to be addressed.
Try installing matplotlib without either Numeric or numarray -- I dont
think you will get very far.

C.

FYI: Here's a sample script for the bug report (if I understand what you're 
trying to do).

Add the following line to the polar_demo.py right before show:

ax.set_rmax( .8 )

And then you get the attached picture.  It looks like the polar axis 
doesn't respond to changes in the maximum radial value to display (even 
though the axis implements the set_rmax method just for that).

Ted


At 12:38 PM 9/30/2005, Stephen Boulet wrote:
>
>
>Thanks for the response.
>
>I have a plot that has a maximum magnitude of about 0.2. I'd like to set the
>radius of the plot circle to 1.
>
>Stephen
>
>
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