matplotlib-users Mailing List for matplotlib

> From: Jerzy Karczmarczuk [mailto:jer...@un...] 
> Sent: Sunday, May 27, 2012 12:56
> 
> Gordon Hardmant :
> > I ...cannot find a simple way to stop a curve being drawn once it crosses
> > another curve. In the attached example, I am trying to draw the solid
> > curve only until it intersects the dashed one. I have tried using the
> > numpy.where() method, but it does not seem to be the right way to go
> > about it- I end up having to write FOR loops and so on, and that does
> > not make use of the vectorization advantages of numpy.
> Try to insert just before plot(...) the following two lines:
> 
> igc=np.sign(ig_bdry-ig_d2)
> ig_d2[igc!=igc[1] ]=np.nan
Or, if you want to preserve the original data, index it with a boolean array:
 under = (ig_d2 <= ig_bdry)
 plt.plot(vg[under], ig_d2[under])
If you need to determine the intersection more precisely, you could define a
function of vg, V, L, Ts, and d that returns the difference between ig_CRM and
ig_CCM for those parameters, then use a root-finding routine [1] to
numerically find the vg for which that function returns essentially zero.
[1] http://docs.scipy.org/doc/scipy/reference/optimize.html#root-finding

On 05/31/2012 10:12 AM, Tony Yu wrote:
>
>
> On Thu, May 31, 2012 at 10:03 AM, Mark Bakker <ma...@gm... 
> <mailto:ma...@gm...>> wrote:
>
> OK. Got it. That is not what I was looking for.
>
> But, why the leading $ sign? Just as an example? The $ sign shows
> up in the cursor coordinate now. Is that what was supposed to
> happen (it is confusing with the $ sign also being used for
> mathtext formatting, as you know).
>
> Thanks,
>
> Mark
>
> I'm guessing that the example was displaying millions of dollars along 
> the y-axis. The dollar sign can be confusing, but it's nice to know 
> that the mathtext parser doesn't get confused ;)
>
The mathtext parser doesn't kick in unless there is a *pair* of dollar 
signs.
Mike

On Thu, May 31, 2012 at 10:03 AM, Mark Bakker <ma...@gm...> wrote:
> OK. Got it. That is not what I was looking for.
>
> But, why the leading $ sign? Just as an example? The $ sign shows up in
> the cursor coordinate now. Is that what was supposed to happen (it is
> confusing with the $ sign also being used for mathtext formatting, as you
> know).
>
> Thanks,
>
> Mark
>
>
I'm guessing that the example was displaying millions of dollars along the
y-axis. The dollar sign can be confusing, but it's nice to know that the
mathtext parser doesn't get confused ;)
-Tony

OK. Got it. That is not what I was looking for.
But, why the leading $ sign? Just as an example? The $ sign shows up in the
cursor coordinate now. Is that what was supposed to happen (it is confusing
with the $ sign also being used for mathtext formatting, as you know).
Thanks,
Mark
On Thu, May 31, 2012 at 3:49 PM, Tony Yu <ts...@gm...> wrote:
>
>
> On Thu, May 31, 2012 at 9:31 AM, Mark Bakker <ma...@gm...> wrote:
>
>> I looked at the example of overriding the default reporting of coords,
>> which is here:
>>
>> http://matplotlib.sourceforge.net/examples/pylab_examples/coords_report.html
>>
>> from pylab import *
>>
>> def millions(x):
>> return '$%1.1fM' % (x*1e-6)
>>
>> x = rand(20)
>> y = 1e7*rand(20)
>>
>> ax = subplot(111)
>> ax.fmt_ydata = millions
>> plot(x, y, 'o')
>>
>> show()
>>
>> I don't understand what the millions function does (with a $ and M ?).
>> In fact, I get the exact same result when I delete the line
>>
>> ax.fmt_ydata = millions
>>
>> Any thoughts?
>>
>
> Hi Mark,
>
> It's a bit confusing, but there's actually two different types of
> formatters. You're most likely looking for major/minor tick formatters (
> example<http://matplotlib.sourceforge.net/examples/api/engineering_formatter.html>).
> In the above example, the *cursor coordinate* is reformatted. In an
> interactive window, you should see the current cursor position in the lower
> left (this may depend on the backend)---that's the value that should be
> reformatted by the `millions` function.
>
> Best,
> -Tony
>
>

On Thu, May 31, 2012 at 9:31 AM, Mark Bakker <ma...@gm...> wrote:
> I looked at the example of overriding the default reporting of coords,
> which is here:
>
> http://matplotlib.sourceforge.net/examples/pylab_examples/coords_report.html
>
> from pylab import *
>
> def millions(x):
> return '$%1.1fM' % (x*1e-6)
>
> x = rand(20)
> y = 1e7*rand(20)
>
> ax = subplot(111)
> ax.fmt_ydata = millions
> plot(x, y, 'o')
>
> show()
>
> I don't understand what the millions function does (with a $ and M ?).
> In fact, I get the exact same result when I delete the line
>
> ax.fmt_ydata = millions
>
> Any thoughts?
>
Hi Mark,
It's a bit confusing, but there's actually two different types of
formatters. You're most likely looking for major/minor tick formatters (
example<http://matplotlib.sourceforge.net/examples/api/engineering_formatter.html>).
In the above example, the *cursor coordinate* is reformatted. In an
interactive window, you should see the current cursor position in the lower
left (this may depend on the backend)---that's the value that should be
reformatted by the `millions` function.
Best,
-Tony

I looked at the example of overriding the default reporting of coords,
which is here:
http://matplotlib.sourceforge.net/examples/pylab_examples/coords_report.html
from pylab import *
def millions(x):
return '$%1.1fM' % (x*1e-6)
x = rand(20)
y = 1e7*rand(20)
ax = subplot(111)
ax.fmt_ydata = millions
plot(x, y, 'o')
show()
I don't understand what the millions function does (with a $ and M ?).
In fact, I get the exact same result when I delete the line
ax.fmt_ydata = millions
Any thoughts?

Le jeudi 31 mai 2012 à 09:31 +0300, Yasin Selçuk Berber a écrit :
> im getting that result.
> but just wanted to know, could "takes first row and put it most
> bottom....then take second....etc" expression be accepted as harmless or
> not.
Seems to, it depends on the interpretation of the expression :)
If you are thinking about data copying, IMO there is no extra copy of
the data compared to any other origin choice. You could also say that
rows of the array are displayed bottom-up for origin='lower' and
top-down for origin='upper'

im getting that result.
but just wanted to know, could "takes first row and put it most
bottom....then take second....etc" expression be accepted as harmless or
not.
2012年5月30日 Tony Yu <ts...@gm...>
>
> On Tue, May 29, 2012 at 5:31 AM, Yasin Selçuk Berber <
> yas...@gm...> wrote:
>
>>
>> Hi. I want to make sure how imshow shows a numpy array as image.
>>
>> lets say below is our numpy data array where letter represent data values
>> and numbers represent row/col indices.
>>
>> 0 1 2
>> 0 a b c
>> 1 d e f
>> 2 g h i
>>
>> and lets think imshow's origin is default upper left.
>> Now, if we show our data as an image, the orientation of visual
>> representation of data shouldt change,
>> and seen like below, right?
>>
>> 0 1 2
>> 0 a b c
>> 1 d e f
>> 2 g h i
>>
>> But if we pass origin="lower" keyword to imshow, (as in basemap by
>> default);
>> is this what we expect to see ?
>>
>> 0 1 2
>> 2 g h i
>> 1 d e f
>> 0 a b c
>>
>> To be clear, does imshow with "lower" keyword value;
>>
>> 1-takes first row of data and put it most bottom,
>> 2-then take second row and put it one row upper from most bottom.....etc ?
>>
>> Thanks.
>>
>> --
>> Yasin Selçuk Berber
>> "Bismillah, her hayrın başıdır."
>>
>>
> Hi Yasin,
>
> Yes, your interpretation looks correct to me. Image coordinates typically
> have an origin at the upper left and increase downward and to the right.
> Setting `origin='lower' ` essentially changes `imshow` to use data
> coordinates, which typically have an origin at the bottom left and increase
> upward and to the right.
>
> Do you expect (or get) something different?
>
> Best,
> -Tony
>
>
-- 
Yasin Selçuk Berber
"Bismillah, her hayrın başıdır."

hello all,
i've tried it on my laptop, but got this error at the last line:
 >>> fig.savefig('samplefigure', bbox_extra_artists=(lgd,), 
bbox_inches='tight')
Traceback (most recent call last):
 File "<console>", line 1, in <module>
 File 
"/Users/me/python/virtualenv/bmfvca6/lib/python2.6/site-packages/matplotlib/figure.py", 
line 1084, in savefig
 self.canvas.print_figure(*args, **kwargs)
 File 
"/Users/me/python/virtualenv/bmfvca6/lib/python2.6/site-packages/matplotlib/backend_bases.py", 
line 1894, in print_figure
 in kwargs.pop("bbox_extra_artists", [])]
TypeError: get_window_extent() takes exactly 1 argument (2 given)
does it mean that i need to upgrade to python 2.7 ?
thanks in advance for help,
gerard

On Wednesday, May 30, 2012, Amanda Stott wrote:
> Hello,
>
> I am trying to build matplotlib from source on CentOS. I have installed
> all the dependencies, including numpy, freetype, libpng, etc. I also have
> both the C and C++ compiler (gcc and cgg-c++) installed in /usr/lib/.
> However when running python setup.py install I get the following error
> message:
>
> pymods ['pylab']
> packages ['matplotlib', 'matplotlib.backends',
> 'matplotlib.backends.qt4_editor', 'matplotlib.projections',
> 'matplotlib.testing', 'matplotlib.testing.jpl_units', 'matplotlib.tests',
> 'mpl_toolkits', 'mpl_toolkits.mplot3d', 'mpl_toolkits.axes_grid',
> 'mpl_toolkits.axes_grid1', 'mpl_toolkits.axisartist',
> 'matplotlib.sphinxext', 'matplotlib.tri', 'matplotlib.delaunay', 'pytz',
> 'dateutil', 'dateutil.zoneinfo']
> running install
> running build
> running build_py
> copying lib/matplotlib/mpl-data/matplotlibrc ->
> build/lib.linux-x86_64-2.4/matplotlib/mpl-data
> copying lib/matplotlib/mpl-data/matplotlib.conf ->
> build/lib.linux-x86_64-2.4/matplotlib/mpl-data
> running build_ext
> building 'matplotlib.ft2font' extension
> c++ -pthread -shared build/temp.linux-x86_64-2.4/src/ft2font.o
> build/temp.linux-x86_64-2.4/src/mplutils.o
> build/temp.linux-x86_64-2.4/CXX/IndirectPythonInterface.o
> build/temp.linux-x86_64-2.4/CXX/cxxsupport.o
> build/temp.linux-x86_64-2.4/CXX/cxx_extensions.o
> build/temp.linux-x86_64-2.4/CXX/cxxextensions.o -L/usr/local/lib -L/usr/lib
> -L/usr/local/lib64 -L/usr/lib64 -lfreetype -lz -lstdc++ -lm -o
> build/lib.linux-x86_64-2.4/matplotlib/ft2font.so
> /usr/bin/ld: cannot find -lz
> collect2: ld returned 1 exit status
> error: command 'c++' failed with exit status 1
>
> I have scoured the web with no solution. Please HELP!
>
> Thanks,
>
> --
> Amanda Stott
>
> The error indicates that it can't find libz, which is extremely odd
because if you didnt have it, then most everything else would never work.
 Which centos are you using? How did you install your dependencies?
Ben Root