matplotlib-users Mailing List for matplotlib

Pietro,

Are you sure it is savefig() that is using memory?  Try
commenting out close().  In my case it solved a memory
problem with batch processing.  See recent list postings
for more details.  You may need to add clf() or cla() to
avoid overplotting.

Please let the list know if it works for you without
close() and your matplotlib version to help developers
track down memory leaks or related issues.

Good Luck,

-- David

>Date: Thu, 21 Apr 2005 07:32:13 -0700 (PDT)
>From: Pietro Speroni di Fenizio <pie...@ya...>
>To: mat...@li...
>Subject: [Matplotlib-users] Memory problem with savefig

>Hello, I have been using Matplotlib lately for some
>academic research. It seem to work just fine. The only
>serious problem is a problem with memory. When I run

.
.
.

>def PlotAreaOrganization(data,filename):
>    keys=symbol2color.keys()
>    keys.sort()
>    colors=[]
>    for key in keys:  colors.append(symbol2color[key])
>    fig=figure(dpi=75)
>    area(data,colors)
>    savefig(filename)
>    close(fig)


>Any suggestion? Is there any other way to save a
>picture that might work better?


+_+_+_+_+_+_+_+_+_+_+_+_+_+_+_+_+

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There is beginning interest in this quality library
on AIX 5.x.  Is a port planned, and when might it be
available?
Thanks,
Lila
lc...@ll...

Using matplotlib 0.74.
The default linestyle for contour lines representing values less than 
zero should be dashed.
I have used this in the past ( I guess prior to 0.74) but now the 
behavior is different.
The default appears to be a greyscale color map - all solid lines.
Looking at the code - line 768 of contour.py, the negative lines are 
dashed if Ncolors == 1.
As far as I can tell, there is no way for this to be true. The code 
change to rectify this is trivial,
but I may be missing something.

I could easily be doing something really dumb - but it seems pretty 
straightforward.

Thanks for any help.

--Jim

I found this error message when I import pylab.

from pylab import *

Error message:
Microsoft Visual C++ Runtime Library
Assertion failed!
Program:c\python24\python.exe
File:CXX/cxx_extentions.cxx
Line:1031

Expression: ob_refcnt =3D=3D 0
For information on how your program can cause an assertion
failure, see the Visual C++ documentation on asserts

First I install in new computer python 2.4.1
then the error comes out.

So I tried to reinstall with python 2.4
The problem still comes.

Please help

Pujo

  > So, i create an instance of the class like this:
  >   a=3D Arrow(0,0,5,5,2.0)
  > The problem is i don"t know how to draw the arrow on a figure.
=20
You can add the arrow to the Axes with=20

   ax.add_artist(arrow)
 =20
Is this what you are looking for.    The Axes will implicitly assume
the arrow is in data coordinates, unless you set the transform
instance of the arrow edxplicitly.  Eg, if you do

  arrow.set_transform(ax.transAxes)

where ax is a matplotlib.axes.Axes instance.


  >  i"m trying to generate the smith chart which is very usefull in
electromagnetic domain.
  > In this purpose, i need to draw circle.
  > I try to find in the polar function the way circles are drawn but
i didn"t find it.
  >  Can you told me John how did you draw circles in the polar figure?
=20
You can create an instance of matplotlib.patches.Circle, and add it to
the Axes with ax.add_patch(circ).  Same rules about the transform
applies above.

If you want to create a circular Axes, like polar does, you may want
to add the circle instance to the figure.  I suggest looking at the
code for matplotlib.axes.PolarAxes, where I create the axes background
"circle" with

        self.thetas =3D linspace(0,2*math.pi, self.RESOLUTION)
        verts =3D zip(self.thetas, ones(self.RESOLUTION))
        self.axesPatch =3D Polygon(
            verts,
            facecolor=3Dself._axisbg,
            edgecolor=3DrcParams['axes.edgecolor'],
            )

If you succeed in creating the smith chart, lpease post a patch or an
example, and feel free to ask if you have more questions.  I
understand those are tough charts to create.

JDH

  >  I am trying to scale the y axis like this:
  >   a =3D axes(gca())

This is probably harmless but redundant.  gca creates a new axes if
none exists, so you can do
any of the foloowing
=20
  a =3D gca()
  a =3D subplot(111)
  a =3D axes([0.1, 0.1, 0.8, 0.8])

but I wouldn't do axes(gca())
=20
  >   a.set_ylim((-1.25, 1.25))
=20
  > This works fine when yticks is non-empty. However, if I do
  >    a.set_yticks([]])
  > either before or after the set_ylim call, the y axis is not scaled.
=20
  >  Any suggestions are appreciated.=20
=20
Make sure that you are updating the figure after you change the
properties.  The figure is automatically redrawn after pylab commands
if interactive is True, but afterr calling object setters, you need to
explicitly call draw (if working interactively)

Please post a complete example which exposes the problem, as well as
matplotlib version and backend information.  You can get the latter by
running your script with --verbose-helpful.

JDH

 Grig

  > Hello, I have been using Matplotlib lately for some
  > academic research. It seem to work just fine. The only
  > serious problem is a problem with memory. When I run
  > the following code, I get the memory increasing
  > linearly with the time. Soon (after around 20
  > generations, and 100 times is this part of the program
  > called) I get beyond the limits of my laptop, and the
  > simulation ends. Considering that I need to do at
  > least 200 generations, you can see that it is a
  > serious problem.

You need to give us a little more information, namely what backend you
are using.  Best if you run your script with --verbose-helpful and
post the output it generates,

There are no known signigicant leaks in the Agg backend proper.  If
you use TkAgg to create many new canvases (which the script you posted
does), there is a known leak, and it may be on the tk side.  The
solution is to reuse the same figure canvas rather than creating new
ones.  There is also a small amount of memory that is used up with the
caching of text layout information, which you can clear manually.

Try something like this (untested)

from matplotlib.text import Text
import gc
fig =3D figure()
for i in range(200):
    fig.clear()
    ax =3D fig.subplot(111)
    ax.plot(blah)
    fig.savefig('myfig')
    Text.cached =3D {}
    gc.collect()

See also the FAQ on memory leaks
http://matplotlib.sourceforge.net/faq.html#LEAKS and search the
mailing list archive for "leak" for more inspiration.

Let us know hwat you learn,
JDH

  > I"d like to be able to add text to various (x,y) coordinates. Currently
  > I specify a figsize of (1.3,0.3) and I add as text (via the text
  > method) the value of the last y, right next to that data point.
  > Depending on the actual value, sometimes the text does not fit within
  > the bounds of the figure.=20
=20
  > Is there any way I can enlarge just the figure so that the text can
  > fit, without enlarging the axes? Or is there a better way to solve my
  > problem?

There are a few parameters that affect the relative sizes of all the
figure elements and text

  figsize - passed to the figure command, width and height in inches
  dpi       - passed to the figure command, number of dots per inch
  fontsize - passed to the text command, size of text in points
  axes([l,b,w,h]) - create a custom axes with width and height as
fractions of figure size

By tweaking these parameters, you should be able to place your text
anywhere you want at any size you want.

If this doesn't help, post a complete example and describe what is
wrong and someone may be able to offer pointers

Hi everybody,
Can you help me about two problems?

1. how to draw an arrow
----------------------------------

i'm looking for drawing single arrow (not an arrow field with quiver).
i saw there is an arrow class in the module matplotlib.patches.
So, i create an instance of the class like this:
a= Arrow(0,0,5,5,2.0)
The problem is i don't know how to draw the arrow on a figure.

My goas is to draw several arrows. Each origin of arrows is placed on the x axis. (i.e y=0)
The head of the arrow vary on x and y axes.
Here is an example:
^
/
/
/-----------------> x
        \
         \
         \ /

2. how to draw a circle?
----------------------------------

i'm trying to generate the smith chart which is very usefull in electromagnetic domain.
In this purpose, i need to draw circle.
I try to find in the polar function the way circles are drawn but i didn't find it.
Can you told me John how did you draw circles in the polar figure?

Cheers,
Philippe Collet