matplotlib-users Mailing List for matplotlib

Jeff,

I think you need to delete the WXAgg accelerator module in your "site- 
packages/matplotlib/backends" directory.  It will have a name like  
"_wxagg.so", "_wxagg.pyd", or "_wxagg.dll".

Ken

Thomas Schmelzer wrote:
> Hello experts,
> I have two matrices (one random matrix with entries between -3 and +3 
> and one with entries say between -4 and 4).
> I would like to plot a contourf for both of them with corresponding 
> color scheme (ranging say from -5 to 5).
> I am a newbie, so please apologize the rather low level of this question.
> cheers
> Thomas

The simplest way is to use the same array of contour levels for both. 
Here is a simplest-possible code fragment to illustrate:

from pylab import *
F = 6 * (rand(20,20) - 0.5)
G = 8 * (rand(20,20) - 0.5)
clevs = arange(-5,6)
subplot(2,1,1)
contourf(F, clevs)
colorbar()
subplot(2,1,2)
contourf(G, clevs)
colorbar()
show()

For additional information:
1) In the matplotlib examples directory, look for all the examples that 
use contourf.
2) Look at the contourf (and other) docstrings.

If you are not already using ipython, get it and try it--it makes the 
experimentation and learning much easier.

Eric

Johann Cohen-Tanugi wrote:
> hello,
> is there a quick way to get a figure in greyscale?

You can do something like plot([1,2,3], color='0.9'), where the string '0.9' 
denotes the gray scale of the plotted line. See also `help plot`, `help colors`.

-- 
cheers,
steve

Random number generation is the art of producing pure gibberish as quickly as 
possible.

hello,
is there a quick way to get a figure in greyscale?
thanks,
Johann

I have this problem with the embedding samples that use wxagg. Otherwise, I
have no problem.

Jeff > do you import something using wxagg ?

Matthieu

2007/11/12, Michael Droettboom <md...@st...>:
>
> Can you send the entire traceback you get with this error?  I'm curious
> which module is requiring this.
>
> Also, if you start a python console and type "import wx", do you get
> this error?
>
> Cheers,
> Mike
>
> Jeff Peery wrote:
> > Hello, thanks for the response. I changed my matplotlibrc file from
> > 'WxAgg' to 'Wx'. I'm still using wxpython 2.8 and matplotlib 0.90.1, and
> > I am still getting the error that wxmsw26uh_vc.dll cannot be found. what
> > else can I do? can I just put this file in the place that it is trying
> > to look?
> >
> > thanks,
> > Jeff
> >
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> --
> Michael Droettboom
> Science Software Branch
> Operations and Engineering Division
> Space Telescope Science Institute
> Operated by AURA for NASA
>
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-- 
French PhD student
Website : http://miles.developpez.com/
Blogs : http://matt.eifelle.com and http://blog.developpez.com/?blog=92
LinkedIn : http://www.linkedin.com/in/matthieubrucher

Can you send the entire traceback you get with this error?  I'm curious 
which module is requiring this.

Also, if you start a python console and type "import wx", do you get 
this error?

Cheers,
Mike

Jeff Peery wrote:
> Hello, thanks for the response. I changed my matplotlibrc file from 
> 'WxAgg' to 'Wx'. I'm still using wxpython 2.8 and matplotlib 0.90.1, and 
> I am still getting the error that wxmsw26uh_vc.dll cannot be found. what 
> else can I do? can I just put this file in the place that it is trying 
> to look?
>  
> thanks,
> Jeff
> 
> __________________________________________________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
> 
> 
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-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

Hello experts,
I have two matrices (one random matrix with entries between -3 and +3 and
one with entries say between -4 and 4).
I would like to plot a contourf for both of them with corresponding color
scheme (ranging say from -5 to 5).
I am a newbie, so please apologize the rather low level of this question.
cheers
Thomas

Hi,

> > There 
> > may be a reason it was done in the less straightforward way that aren't
> > obvious to you or I (perhaps to ease embedding... just guessing).
> 
> I don't think we can use the QMainWindow's addToolBar for this. It creates 
a 
> single toolbar for the entire window, but what if we want to add two 
> canveses, each with its own toolbar, in a single window? I am writing an 
> application that does this.

Well, technically this is not a problem, since you can add several toolbars
with addToolBar. But well, you are right, this would look awkward, two
times the same toolbar... But anyhow, I am calling addToolBar in the class
FigureManagerQT, which is not able to handle more than one plot in a 
window it seems to me (am I missing something?). If, on the other
hand, you create your own QMainWindow, there is no problem putting the
toolbar like it was done classically. I added an example for that to the
patch request ID 1828848 (Qt4 backend improvement). I don't know your
code, but it is possible, maybe even probable, that it works even
with my modifications, as I did not change the class structure.
Only possible incompatibilities I could see is if you are inheriting
FigureManagerQT and doing something in there.

So in the end I think my patch is still a good idea. It might be needed
to change it to keep compatibility with old code, though.

Greetings,

Martin

John,

On Nov 10, 2007 2:41 AM, John Hunter <jd...@gm...> wrote:
> > Now that is a well focused question.

Thank  you for your teaching. ^_^.

>
> A little googling revealed that
> > when a gtk drawing area (eg an matplotlib canvas) is placed in a gtk
> > notebook, it needs to have the focus to receive key press events.

Thank you for the information. It's really the point.

> I had hoped it would be enough to do
>   canvas.grab_focus()
> but apparently it is not (upon testing).  But the suggestion from the
> link above to use TAB to grab the focus worked in my tests.

> With a little more testing, I find if I grab the focus after showing
> the window that the notebook is in, it works as expected:

Thank you for your patient test.
Just for information, it is also workable to set current page for
notebook firstly and then grab focus for the drawing area, such as
notebook.set_current_page(pageno)
canvas.grab_focus()     #canvas is the view embedded in page $pageno

Thanks again for your help.
-- 
sunzen
<<freedom & enjoyment>>

Thanks

That was just what I was looking for.
The bihistogram solution is interesting too, but I think I will to
with alpha since I might want to use a log y scale.

Regards
Neil

On Nov 12, 2007 3:06 PM, Eric Firing <ef...@ha...> wrote:
>
> Neil M wrote:
> > Hello,
> >
> > Is it possible to plot two histograms on the same axis without having
> > the bars on top of each other.
> >
> > I'm trying to determine how similar a distribution of activity is
> > between a large data set and a small subset.
> >
> > I have 2 million records with a last activity date.  I can plot both
> > the sample and the full population on a normalized histogram, and in
> > different colours but the later plot covers smaller values of the
> > earlier one.
> >
> > Thanks
> > Neil
>
> Neil,
>
> I can think of two alternatives.  If one of the two distributions has
> all values higher than the other, so you want it to be behind, then you
> can use the zorder property of the patches.  From your description it
> sounds like this is the case.  If not, however, you can set the alpha
> property so that both sets of bars are semi-transparent.
>
> Both of these properties can be passed in as kwargs to the hist() function:
>
> hist(randn(200), edgecolor='r', zorder=5, alpha=0.5)
> hist(randn(500), edgecolor='g', zorder=4, alpha=0.5)
>
> Eric
>
> >
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>
>

Neil M wrote:
> Hello,
> 
> Is it possible to plot two histograms on the same axis without having
> the bars on top of each other.
> 
> I'm trying to determine how similar a distribution of activity is
> between a large data set and a small subset.
> 
> I have 2 million records with a last activity date.  I can plot both
> the sample and the full population on a normalized histogram, and in
> different colours but the later plot covers smaller values of the
> earlier one.
> 
> Thanks
> Neil

Neil,

I can think of two alternatives.  If one of the two distributions has 
all values higher than the other, so you want it to be behind, then you 
can use the zorder property of the patches.  From your description it 
sounds like this is the case.  If not, however, you can set the alpha 
property so that both sets of bars are semi-transparent.

Both of these properties can be passed in as kwargs to the hist() function:

hist(randn(200), edgecolor='r', zorder=5, alpha=0.5)
hist(randn(500), edgecolor='g', zorder=4, alpha=0.5)

Eric

> 
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> Still grepping through log files to find problems?  Stop.
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See below for Antonio Gonzalez solution (last year)  that I have started 
using and happy with it

Neil M wrote:
> Hello,
>
> Is it possible to plot two histograms on the same axis without having
> the bars on top of each other.
>
> I'm trying to determine how similar a distribution of activity is
> between a large data set and a small subset.
>
> I have 2 million records with a last activity date.  I can plot both
> the sample and the full population on a normalized histogram, and in
> different colours but the later plot covers smaller values of the
> earlier one.
>
> Thanks
> Neil
>   

-------- Original Message --------
Subject: 	Re: [Matplotlib-users] plotting overlapped histograms
Date: 	Mon, 13 Nov 2006 19:02:03 +0100
From: 	Antonio Gonzalez <Ant...@ki...>
To: 	David E. Konerding <dek...@lb...>
CC: 	Mat...@li...
References: 	<455...@lb...>



To compare two histograms you can plot a bihistogram as suggested on
http://www.itl.nist.gov/div898/handbook/eda/section3/bihistog.htm

The little function I've written to do so is below. See if it helps.

Antonio



import scipy
from pylab import figure

def bihist(y1, y2, nbins=10, h=None):
	'''
	Bihistogram.
	h is an axis handle. If not present, a new figure is created.
	'''
	if h is None: h = figure().add_subplot(111)
	xmin = scipy.floor(scipy.minimum(y1.min(), y2.min()))
	xmax = scipy.ceil(scipy.maximum(y1.max(), y2.max()))
	bins = scipy.linspace(xmin, xmax, nbins)
	n1, bins1, patch1 = h.hist(y1, bins)
	n2, bins2, patch2 = h.hist(y2, bins)
	# set ymax:
	ymax = 0
	for i in patch1:
		height = i.get_height()
		if height > ymax: ymax = height
	# invert second histogram and set ymin:
	ymin = 0
	for i in patch2:
		height = i.get_height()
		height = -height
		i.set_height(height)
		if height < ymin: ymin = height
	h.set_ylim(ymin*1.1, ymax*1.1)		
	h.figure.canvas.draw()

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Hello,

Is it possible to plot two histograms on the same axis without having
the bars on top of each other.

I'm trying to determine how similar a distribution of activity is
between a large data set and a small subset.

I have 2 million records with a last activity date.  I can plot both
the sample and the full population on a normalized histogram, and in
different colours but the later plot covers smaller values of the
earlier one.

Thanks
Neil