matplotlib-users Mailing List for matplotlib

Hi all,

I'm using a matplotlib.widgets.Slider on my animated figure. Sometime, I
want to refresh the maximum value of the slider (since new values to plot
were generated).

Is it possible to update the "valmax" value of the slider? If not, is it
possible to delete the slider and create a new one?

Thanx!

wukan, on 2011-02-14 23:39,  wrote:
> Hi ,When I use matplotlib to draw 2D graphics in django web site，I encounter
> a problem.
> when server users  use matplotlib to draw graphics simultaneously  will
> cause website collapse.
> when one user use matplotlib to draw graphics will have no problem.

Is there an error / stack trace generated? Can you give an
example of how you are using matplotlib from django? 

I can imagine there being some issue if you are using the pyplot
interface to deal with all user requests (e.g. plt.plot, instead
of allocating an axes object for each user and calling ax.plot). 

There's no way for us to know unless you provide more details.

> i suppose matplotlib doesnot support multithreading drawing.
> so i put the draw function in a thread . it can't work as before.

I don't follow.
 
> so why matplotlib doesnot support multithreading drawing?
> How to solve this problem.

Depending on the load, the nature of desired plots,  and the need
for user intervention, you might be able to get around the issues
you're having just by spawning a new process to do the plotting.

P.S. 
I try to answer all of the questions I feel capable of answering
on the mailing list, there is no need to send duplicates of
mailing list questions directly to me.

best,
-- 
Paul Ivanov
314 address only used for lists,  off-list direct email at:
http://pirsquared.org | GPG/PGP key id: 0x0F3E28F7 

Bala subramanian, on 2011-02-15 16:06,  wrote:
> Friends,
> I created a histogram plot using data files that have discrete values
> (sample file attached 'test.dat').However when i view the plot, i see that
> the bars are not located exactly over the values. For example in the
> attached figure (test.png), i see a bar (gray) placed between values 1 and
> 2, while there is no such value between 1 and 2. Precisely i would like to
> know how to make histogram for discrete data values.

Hi Bala,

Hist by default will make 10 bins with the same width, so
depending on the distribution of your data, it will shift the
locations of the bins (which is the effect you are seeing). 

What you'll want to do is pass the 'bins' keyword to ax.hist to
avoid this. From the docstring
  
*bins*:
  Either an integer number of bins or a sequence giving the
  bins.  If *bins* is an integer, *bins* + 1 bin edges
  will be returned, consistent with :func:`numpy.histogram`
  for numpy version >= 1.3, and with the *new* = True argument
  in earlier versions.  Unequally spaced bins are supported if
  *bins* is a sequence.


Here's an example:

In [8]: a = np.random.randint(20,size=(20))

In [9]: ax = plt.gca()

In [10]: ax.hist(a,bins=np.arange(a.min(),a.max()+2,1)-.5)
Out[10]: 
(array([1, 3, 1, 1, 0, 3, 1, 0, 0, 0, 0, 2, 1, 0, 1, 1, 0, 0, 2,
3]),
 array([ -0.5,   0.5,   1.5,   2.5,   3.5,   4.5,   5.5,   6.5,
7.5,
         8.5,   9.5,  10.5,  11.5,  12.5,  13.5,  14.5,  15.5,
16.5,
        17.5,  18.5,  19.5]),
 <a list of 20 Patch objects>)

In [11]: ax.hist(a) # the default bins=10
(array([4, 2, 3, 1, 0, 2, 1, 2, 0, 5]),
 array([  0. ,   1.9,   3.8,   5.7,   7.6,   9.5,  11.4,  13.3,
15.2,
        17.1,  19. ]),
 <a list of 10 Patch objects>)


best,
-- 
Paul Ivanov
314 address only used for lists,  off-list direct email at:
http://pirsquared.org | GPG/PGP key id: 0x0F3E28F7 

On Tue, Feb 8, 2011 at 8:43 PM, Benjamin Root <ben...@ou...> wrote:

> On Tue, Feb 8, 2011 at 5:53 PM, Paul Leopardi <pau...@ii...>wrote:
>
>> Hi Ben,
>> On Wed, 9 Feb 2011 03:15:19 AM you wrote:
>> > As formatted, the code would not run.  I presume that everything after
>> "for
>> > j in range(0,M):" should be indented?  When I did that and ran it in
>> > ipython, I could not reproduce your problem.  What version of matplotlib
>> > are you running?
>>
>> Thanks for your continued close attention to this undoubted problem.
>>
>> Your email system mangled the indentation. The correct indentation is
>> displayed at
>> http://sourceforge.net/mailarchive/message.php?msg_id=27020771
>>
>> I have also included a copy of the script matplotlib_bug_example.py with
>> this
>> message. [*Not* posted to the list.] Here is how I run it:
>>
>> ipython -pylab
>> Python 2.6.2 (r262:71600, Oct 28 2010, 20:54:41)
>> Type "copyright", "credits" or "license" for more information.
>>
>> IPython 0.10 -- An enhanced Interactive Python.
>> ?         -> Introduction and overview of IPython's features.
>> %quickref -> Quick reference.
>> help      -> Python's own help system.
>> object?   -> Details about 'object'. ?object also works, ?? prints more.
>>
>>  Welcome to pylab, a matplotlib-based Python environment.
>>  For more information, type 'help(pylab)'.
>>
>> In [1]: run matplotlib_bug_example.py
>>
>> My original post
>> http://sourceforge.net/mailarchive/message.php?msg_id=27016368
>> listed what I thought were the relevant versions:
>>
>> Quote
>> I am using openSUSE 11.2 with
>> python-base-2.6.2-6.7.1.x86_64
>> python-matplotlib-1.0.1-20.1.x86_64
>> python-matplotlib-tk-1.0.1-20.1.x86_64
>> python-matplotlib-wx-1.0.1-20.1.x86_64
>> Unquote
>>
>> I have since run the script on a second machine which uses Ubuntu Karmic,
>> with
>> identical results.
>>
>> Versions in brief:
>> Linux linfinit 2.6.31.12-0.1-default #1 SMP PREEMPT 2010-12-10 11:18:32
>> +0100
>> x86_64 x86_64 x86_64 GNU/Linux
>>
>> IPython-0.10-3.2.noarch
>> python-2.6.2-6.7.1.x86_64
>> python-matplotlib-1.0.1-20.1.x86_64
>> python-matplotlib-tk-1.0.1-20.1.x86_64
>> python-matplotlib-wx-1.0.1-20.1.x86_64
>> python-numpy-1.5.0-17.2.x86_64
>> python-tk-2.6.2-6.7.1.x86_64
>>
>> Linux cheeze 2.6.31-22-generic #70-Ubuntu SMP Wed Dec 1 23:51:13 UTC 2010
>> i686 GNU/Linux
>>
>> ipython              0.10-1
>> python               2.6.4-0ubuntu1
>> python-matplotlib    0.99.0-1ubuntu1
>> python-numpy         1:1.3.0-3
>> python-tk            2.6.3-0ubuntu1
>>
>>
>> I have included a listing showing all versions of all packages with names
>> containing the string "python", on both machines. [*Not* posted to the
>> list.]
>> Best, Paul
>>
>>
> Trying out the script on another machine of mine, I was able to reproduce
> the problem.  I will have to see what is the difference between my two
> computers that would cause the other one to work perfectly fine.
>
> Ben Root
>
>

Paul,

I have not figured out what is causing the difference between my computers.
This might be backend-dependent (and maybe version-dependent).  Have you
tested your code on different backends?

Ben Root

On Tue, Feb 15, 2011 at 9:24 AM, Sebastian Busch <web...@th...> wrote:
> Dear list,
>
> if I do a
>
> plot([1,2],[1,2])
> plot([1,2],[1,3])
> plot([1,2],[1,4])
>
> I will get three lines. All have linestyle='-', the colour is changed
> automatically: blue, green, red, ...
>
> Can I change this behaviour to: All have the colour black, and the
> linestyle is changed /automatically/ '-', '--', '-.', ...?

You can use itertools.cycle, that will repeatedly loop over a sequence of items:

import matplotlib.pyplot as pl
from itertools import cycle
styles = cycle(['k-', 'k--', 'k-.'])
plot([1,2], [1,2], styles.next())
plot([1,2], [1,3], styles.next())
plot([1,2], [1,4], styles.next())

Ryan

-- 
Ryan May
Graduate Research Assistant
School of Meteorology
University of Oklahoma

2011/2/14 Gaël KANEKO <kan...@ho...>

>  Hi,
> I have some problems to plot a 3d plot_surface (and contour plot) in log
> scale (y and z or x,y and z).
> There is nothink in the help sections of thus plot to plot them in log
> scale (neither in thus plot code commentary).
> I tried to find a solution by myself (many try as "log=True",
> "xscale='log'", "scale='log'", or "set_xscale('log')"...) but it doesn't
> work.
> I tried to use "LogFormatter" (ticker) but i failed (maybe I am doing
> something wrong (I am a newbe) but i tried many things).
> I try to found a solution on forums and this mailing list and what i found
> nearest of my problem is this topic:
>
> http://stackoverflow.com/questions/3909794/plotting-mplot3d-axes3d-xyz-surface-plot-with-log-scale
> ‏ They said this problem had no solution. Is it true? have somebody solved
> this problem?
>
> An other solution is to plot log(Data) and change ticks with "set_ticks"
> (for exemple) but it seems to only work with 2D plot. I tried too :(
>
> To be unterstanding easier, this is an exemple of the code to plot in log
> scale:
>     import matplotlib.pyplot as plt#   (i am under '1.0.0')
>     import numpy as np
>
>     #Data
>     x = np.logspace(0, 4, 10)
>     y = np.logspace(0, 4, 10)
>     Z = np.arange(100).reshape((10,10))
>
>     #Min and Max for x,y and Z
>     minx=np.min(x)
>     maxx=np.max(x)
>     miny=np.min(y)
>     maxy=np.max(y)
>     minz=np.min(Z)
>     maxz=np.max(Z)
>
>     #figure
>     fig = plt.figure()
>     ax = fig.gca(projection='3d')
>
>
>     ax.plot_surface(X, Y, Z, rstride=8, cstride=8, alpha=0.3)
>     cset = ax.contour(X, Y, Z, zdir='z', offset=minz)
>     cset = ax.contour(X, Y, Z, zdir='x', offset=minx)
>     cset = ax.contour(X, Y, Z, zdir='y', offset=miny)
>
>     ax.set_xlabel("X")
>     ax.set_xlim3d(minx,maxx)
>     ax.set_ylabel("Y")
>     ax.set_ylim3d(miny,maxy)
>     ax.set_zlabel("Z")
>     ax.set_zlim3d(minz,maxz)
>     fig.savefig("plot00.png")
>
>
>
> Has someone got a solution?
> Thanks!
> Regards,
> Gaël
>
>
I can confirm (with a modified version of your script) that mplot3d does not
properly handle non-linear scaling.  While it is possible to set the axis
scale through a command like:

ax.w_xaxis.set_scale('log')

but the placement of the tickers are wrong and it fails because mplot3d does
some weird stuff with the ticker formatter rather than just letting the
formatter do its job.

I will look into this further to see if I can fix this.

Ben Root

Dear list,

if I do a

plot([1,2],[1,2])
plot([1,2],[1,3])
plot([1,2],[1,4])

I will get three lines. All have linestyle='-', the colour is changed
automatically: blue, green, red, ...

Can I change this behaviour to: All have the colour black, and the
linestyle is changed /automatically/ '-', '--', '-.', ...?

Thanks in advance,
Sebastian.

On 2/14/11 4:54 PM, Benjamin Root wrote:
> On Mon, Feb 14, 2011 at 5:30 PM, John Hunter <jd...@gm... 
> <mailto:jd...@gm...>> wrote:
>
>     On Sun, Feb 13, 2011 at 11:45 PM, Tom Flannaghan <tj...@ca...
>     <mailto:tj...@ca...>> wrote:
>
>     > It would also be helpful if anyone has suggestions on a
>     particular issue I had.
>     > Currently, to plot variable-width lines (i.e. streamlines2.png)
>     I use a plot
>     > command for each line segment which is very slow and nasty. Is
>     there a better
>     > way I'm missing?
>
>     You probably want to use a compound path (one object for the entire
>     plot).  See the tutorial at
>     http://matplotlib.sourceforge.net/users/path_tutorial.html, in
>     particular the compound path for the histogram example near the end,
>     and let me know if you have any questions.
>
>     JDH
>
>
> Personally, I am more a fan of Ray's version, although Tom's version 
> would integrate more nicely with the current mpl codebase.  There are 
> some nice features with Ray's version such as allowing to choose 
> density in both x and y directions.
>
> I guess the major question is which style do we like better?  Maybe we 
> could use both of these code bases to come up with a nice, generalized 
> version?
>
> Ben Root
>


Ben, John:  Later this week or next, I'll take a crack at adding both of 
these to quiver.py and axes.py (one under the name "streamlines", the 
other as "streamplot").

-Jeff

-- 
Jeffrey S. Whitaker         Phone  : (303)497-6313
Meteorologist               FAX    : (303)497-6449
NOAA/OAR/PSD  R/PSD1        Email  : Jef...@no...
325 Broadway                Office : Skaggs Research Cntr 1D-113
Boulder, CO, USA 80303-3328 Web    : http://tinyurl.com/5telg

Hi Aman,

Thanks a lot for your help and providing me the link to the function. It
sorted out my query :)

Cheers
Omer


On Tue, Feb 15, 2011 at 14:44, Aman Thakral <ama...@gm...> wrote:

> Hi Omer,
>
> use the subplots_adjust keyword argument (or click on the adjust
> subplots icon in the navigation toolbar at the bottom of the figure).
>
>
> http://matplotlib.sourceforge.net/api/figure_api.html#matplotlib.figure.Figure.subplots_adjust
>
> -Aman
>
> On Tue, Feb 15, 2011 at 6:05 AM, Omer Khalid <okh...@gm...>
> wrote:
> > Hi,
> > I am trying to create two subplots in the same figure. Currently, the
> x-axis
> > of first plot overlaps with the title of second plot.
> > I was wondering if there is a function for figure object that allows to
> > create vertical space between two plots so that the axis and title text
> > doesn't overlap?
> > Regards
> > omer
> >
> ------------------------------------------------------------------------------
> > The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE:
> > Pinpoint memory and threading errors before they happen.
> > Find and fix more than 250 security defects in the development cycle.
> > Locate bottlenecks in serial and parallel code that limit performance.
> > http://p.sf.net/sfu/intel-dev2devfeb
> > _______________________________________________
> > Matplotlib-users mailing list
> > Mat...@li...
> > https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> >
> >
>

Hi Omer,

use the subplots_adjust keyword argument (or click on the adjust
subplots icon in the navigation toolbar at the bottom of the figure).

http://matplotlib.sourceforge.net/api/figure_api.html#matplotlib.figure.Figure.subplots_adjust

-Aman

On Tue, Feb 15, 2011 at 6:05 AM, Omer Khalid <okh...@gm...> wrote:
> Hi,
> I am trying to create two subplots in the same figure. Currently, the x-axis
> of first plot overlaps with the title of second plot.
> I was wondering if there is a function for figure object that allows to
> create vertical space between two plots so that the axis and title text
> doesn't overlap?
> Regards
> omer
> ------------------------------------------------------------------------------
> The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE:
> Pinpoint memory and threading errors before they happen.
> Find and fix more than 250 security defects in the development cycle.
> Locate bottlenecks in serial and parallel code that limit performance.
> http://p.sf.net/sfu/intel-dev2devfeb
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>
>

Hi,

I am trying to create two subplots in the same figure. Currently, the x-axis
of first plot overlaps with the title of second plot.

I was wondering if there is a function for figure object that allows to
create vertical space between two plots so that the axis and title text
doesn't overlap?

Regards
omer

Hi everyone,

I'm not quite sure what to call my problem so searching for it is 
difficult, but I'll try and describe it the best I can:

Matplotlib in python on OSX seems to have an issue with the pan/zoom 
tool.  When I click it and drag the plot around, it does not update 
until I release the mouse.  I've used this function on other *nix 
machines and it seems to be fine.  Here's a quick video describing what 
I mean if my description is unclear: 
http://www.youtube.com/watch?v=_cqUGpHGrl0

I have tried to switch the backend to osx in the matplotlibrc file, but 
the result is the same.  Any help you can provide would be greatly 
appreciated.  Thanks!

-Robert

jules hummon, on 2011-02-14 07:23,  wrote:
> Feel free to 'save and run', pass along, or ignore.
> This was my valentine's day present today.

Thank you for sharing! I took the liberty of livening it up for
my sweetheart.

#---------------------------------------------------
# hohumheartbeat.py - a more lively hohumheart.py ;)

import numpy as np
import matplotlib as mpl
import matplotlib.pyplot as plt
from matplotlib.patches import Polygon

# force square figure and square axes looks better for polar, IMO
width, height = mpl.rcParams['figure.figsize']
size = min(width, height)
# make a square figure
fig = plt.figure(figsize=(size, size))
ax = fig.add_axes([0.1, 0.1, 0.8, 0.8], polar=True, axisbg='#ffffff')
ax2 = fig.add_axes([0.45, .9, 0.1, 0.1], polar=True, axisbg='#ffffff')

ax.set_rmax(2.0)
ax2.set_rmax(4.0)
ax2.spines['polar'].set_visible(False)
ax2.patch.set_alpha(.3)
for a in ax,ax2:
  a.set_xticks([])
  a.set_yticks([])
  ax.grid(False)

theta = np.linspace(0,1,100)*np.pi*2
r = 1*(1-np.cos(theta))

ncards = 5
step = 2*np.pi/ncards
pdict = dict(fc='r',ec='k', alpha=.5)
for ii in range(ncards):
    tr = np.column_stack((theta+ii*step, r))
    ax.add_patch(Polygon(tr, **pdict))

# from WolframMath "Heart Curve"
r2 = 2 - 2*np.sin(theta)
r2 += np.sin(theta) * np.sqrt(np.abs(np.cos(theta))) / (np.sin(theta)+1.4)

tr2 = np.column_stack((theta, r2))
ax2.add_patch(Polygon(tr2,**pdict)) # heart

kwargs = dict(transform=ax2.transAxes, va='center', fontsize=20)
ax2.text(0,.45,"I",ha='right',**kwargs)
ax2.text(1,.4,"you",ha='left',**kwargs)

beat =  np.tan(np.linspace(0, np.pi*2, 100))
beat[0:20] = beat[60:80]
beat[-20:] = beat[20:40]
beat -= beat.min()
beat /= beat.max()

i=0; beatlen = len(beat)-1;
def heartbeat(e):
    global i;
    i = (i+1) % (beatlen)
    y = beat[i]
    ax2.set_rmax(y*4. + 4.)
    ax2.draw(ax.figure.canvas.get_renderer())
    ax2.figure.canvas.blit(ax2.bbox)
    #plt.draw()  #use if the last two lines cause trouble

# even your mouse movements make my heart skip a bit!
cid = ax.figure.canvas.mpl_connect('idle_event', heartbeat)

print "ax.figure.canvas.mpl_disconnect(%d)" %cid
print "#run the line above to 'flatline' (stop heartbeat)"
plt.show()

best,
-- 
Paul Ivanov
314 address only used for lists,  off-list direct email at:
http://pirsquared.org | GPG/PGP key id: 0x0F3E28F7