matplotlib-users Mailing List for matplotlib

>    histogram of f(x) is plotted horizontally (on the right) sharing
> the y-axis of axis 1

Typo:

   histogram of f(x) is plotted horizontally (on the LEFT) sharing the
y-axis of axis 1

Is it possible to have a figure with two-plots such that....

   f(x) is plotted against x   on    axis 1  (on the right)

   histogram of f(x) is plotted horizontally (on the right) sharing
the y-axis of axis 1



(sorry, this is proportional font, ascii art)


                        f(x)
                         ^
                          |
                          |
                          |
 counts  <-------- --------->  x


I want count=0 to be on the shared y-axis.  Perhaps log of counts as
well...so normal histogram options.

Thanks.

I am wondering if there is a way to view my data with respect to the
physical size of what my array element is suppose to be.

I have an array that is 60 x 4000 where,
    the first row has a height of 1.4
    the next nine has a height of 1
    the next forty has a height of 0.5
    the next nine has a height of 1
    and the last one has a height of 1.4

When viewing this with contourf or pcolor, the image is more narrow
than it should be.  Is there an easy way to view this properly.

Bryan

--=20
"The game of science can accurately be described as a never-ending
insult to human intelligence."=09- Jo=E3o Magueijo

Hi,

I was able to make Scatter3D erroneously shift its plot down by 0.2. I
have no idea why this happened but I can reproduce it.

Basically I have data ranging from 0.0 to -1.0 over an x,y grid but
Scatter3D displays the data shifted down by 0.2!!!

I have included some screen shots of this problem, a python program
which creates it, and the data that I used.

Any help that could be given would be much appreciated.

Karl Edler

On Sun, 25 Nov 2007, Jouni K Sepp=E4nen wrote:

> x,y =3D zip(*[(15.0, 0.0), (30.0, 1.0), (70.0, 1.0), (85.0, 0.0)])

Jouni,

   Thank you for pointing this out to me. I see that it's a builtin functio=
n
similar to map that assembles the first element of each tuple into a list
for the first variable, and the second element of each tuple into a list fo=
r
the second variable. How useful for my plotting needs!

Rich

--=20
Richard B. Shepard, Ph.D.               |  Integrity            Credibility
Applied Ecosystem Services, Inc.        |            Innovation
<http://www.appl-ecosys.com>     Voice: 503-667-4517      Fax: 503-667-8863

On Sun, 25 Nov 2007, Jouni K Sepp=E4nen wrote:

> You are looking for the classic "unzip" trick:
> x,y =3D zip(*[(15.0, 0.0), (30.0, 1.0), (70.0, 1.0), (85.0, 0.0)])

Jouni,

   That's totally new to me. I'll go find out what it is and how it works i=
ts
magic.

Thank you,

Rich

--=20
Richard B. Shepard, Ph.D.               |  Integrity            Credibility
Applied Ecosystem Services, Inc.        |            Innovation
<http://www.appl-ecosys.com>     Voice: 503-667-4517      Fax: 503-667-8863

Rich Shepard <rshepard@...> writes:

>      x,y = [(15.0, 0.0), (30.0, 1.0), (70.0, 1.0), (85.0, 0.0)]
> ValueError: too many values to unpack

You are looking for the classic "unzip" trick:

x,y = zip(*[(15.0, 0.0), (30.0, 1.0), (70.0, 1.0), (85.0, 0.0)])

-- 
Jouni

On Sun, 25 Nov 2007, Darren Dale wrote:

> you need a "," after that "(70,1.0)"

   Thanks, Darren. Not enough caffine, I guess.

   However, now I get:

Traceback (most recent call last):
   File "trapezoid.py", line 4, in ?
     x,y = [(15.0, 0.0), (30.0, 1.0), (70.0, 1.0), (85.0, 0.0)]
ValueError: too many values to unpack

which tells me something is still not correct.

Rich

-- 
Richard B. Shepard, Ph.D.               |  Integrity            Credibility
Applied Ecosystem Services, Inc.        |            Innovation
<http://www.appl-ecosys.com>     Voice: 503-667-4517      Fax: 503-667-8863

On Sunday 25 November 2007 12:15:54 pm Rich Shepard wrote:
> x,y = [(15,0.0), (30,1.0), (70,1.0) (85,0.0)]

you need a "," after that "(70,1.0)"

   I need to plot trapezoids as well as left- and right-shouldered straight
line plots. If I specify separate lists for the x values and their
corresponding y values, the plots are generated and displayed as needed.
However, I cannot specify the points as a list of tuples and have matplotlib
accept them.

   Example:
 	x,y = [(15,0.0), (30,1.0), (70,1.0) (85,0.0)]
 	p.plot (x,y)

Yields:
 	Traceback (most recent call last):
 	  File "trapezoid.py", line 4, in ?
 	    x,y = [(15,0.0), (30,1.0), (70,1.0) (85,0.0)]
 	TypeError: 'tuple' object is not callable

   I don't see how to do this in the User Guide, but I'm sure there must be a
way. Please pass me a pointer on how to accomplish this.

Rich

-- 
Richard B. Shepard, Ph.D.               |  Integrity            Credibility
Applied Ecosystem Services, Inc.        |            Innovation
<http://www.appl-ecosys.com>     Voice: 503-667-4517      Fax: 503-667-8863

Wasn't sure where to post this so I'll keep it brief (and I have tried to check forums, FAQ and guides)

I'm a relative noob but have a Tk based GUI running properly and have used Matplotlib successfully in two separate implementations of code. When I try to combine my GUI code with my matplotlib code and then place a  "from pylab import *"  into my code,  I run into problems with the GUI widgets "text" variable "not being expected".  This is before I execute any specific features of pylab.

If I move the import down in my code, after the GUI classes I have created have exited their mainloop, I have no problem.  It seems as if execution of the pylab import interferes with the Tk widgets "text" keyword somehow.  I would prefer to execute my matplotlib "code" iteratively from inside of my gui (as the user picks different data sets and so forth) and not have the program exit my mainloop GUI environment to then plot independently using matplotlib.

The pieces work fine, but it is odd to me that the location of where I place the import determines the success of execution of my code.  Perhaps there is some important information about Tk running a mainloop and importing pylab at the same time that I do not understand.  (I normally execute from double click on the filename.py)  

I can share the code and the rc file but wanted to make sure I was in the right post location first.  Apologies if I misunderstood FAQ direction for problem review.






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On Sun, 25 Nov 2007, Angus McMorland wrote:

> If you change exp -> nx.exp in your definition of gauss1d, all works okay.

Angus,

    Yes, it works just fine. By adjusting the value of the fwhm parameter I
can produce the curves we need for both display and printing.

    Now I can spend some time tomorrow working out the functions for
trapezoidal and shouldered curves (comparatively quite simple), learning how
to embed them in a wxPython panel, and putting two, three, five, or seven
curves on the same axes. The embedded wiki page and User Guide should
provide what I need.

    My thanks to you and everyone else who responded. While I don't yet have
sufficient knowledge to help others on this mail list, I do provide help on
those lists where I've used the software for months or years and can answer
questions posed by others. Perhaps I'll be doing that here, too, soon.

Carpe weekend -- what's left of it,

Rich

-- 
Richard B. Shepard, Ph.D.               |  Integrity            Credibility
Applied Ecosystem Services, Inc.        |            Innovation
<http://www.appl-ecosys.com>     Voice: 503-667-4517      Fax: 503-667-8863

On Sun, 25 Nov 2007, Angus McMorland wrote:

> As I suspected, this is a parameter issue- in this case caused by your use
> of the ath module routines which require scalar input, rather than numpy's
> (or matplotlib's numerix's) array-friendly versions. If you change exp ->
> nx.exp in your definition of gauss1d, all works okay.

   Oh, d'oh! That's what I get for copying without closely examining the
code. With more experience I'll learn the differences between the Python
math functions and the equivalent ones from NumPy.

Many thanks,

Rich

-- 
Richard B. Shepard, Ph.D.               |  Integrity            Credibility
Applied Ecosystem Services, Inc.        |            Innovation
<http://www.appl-ecosys.com>     Voice: 503-667-4517      Fax: 503-667-8863

On 25/11/2007, Rich Shepard <rsh...@ap...> wrote:
> On Sun, 25 Nov 2007, Angus McMorland wrote:
>
> > I'm not completely sure, but I suspect that this is an implementation bug,
> > rather than a version bug, particularly because the line in question isn't
> > involving matplotlib at all. If you post the relevant code
> > (normal-curve.py, by the looks of things), it might be easy to spot the
> > problem.
>
> Angus,
>
>    I've seen the same error trying to plot other curves in the past couple of
> days, but not those using the Boltzmann distribution. Here's the file:
>
> import matplotlib.numerix as nx
> import pylab as p
> from math import *
>
> center = 50.0
> fwhm = 50.0
>
> def fwhm2k(fwhm):
>    '''converts fwhm value to k (see above)'''
>    return fwhm/(2 * nx.sqrt(nx.log(2)))
>
> def gauss1d(r, fwhm, center):
>    '''returns the 1d gaussian given by fwhm (full-width at half-max),
>    and c (centre) at positions given by r
>    '''
>    return exp(-(r-center)**2 / fwhm2k(fwhm)**2)
>
> x = nx.arange(0, 100, 0.1)
> G = gauss1d(x, fwhm, center)
> p.plot(x, G, color='red', lw=2)
> p.axis([0, 100, 0.0, 1.0])
> p.xlabel('Universe of Discourse')
> p.ylabel('Membership Grade')
> p.show()
>

As I suspected, this is a parameter issue- in this case caused by your
use of the ath module routines which require scalar input, rather than
numpy's (or matplotlib's numerix's) array-friendly versions. If you
change exp -> nx.exp in your definition of gauss1d, all works okay.

A.
-- 
AJC McMorland, PhD Student
Physiology, University of Auckland

On Nov 24, 2007 4:17 PM, Rich Shepard <rsh...@ap...> wrote:
> On Sun, 25 Nov 2007, Angus McMorland wrote:

> > I've found it easiest to solve these sorts of bugs by running the code in
> > an ipython shell, with automatic pdb calling. That way you can inspect the
> > values of the parameters in question - one of which is, I think, the
> > problem here.
>
>    I've not run ipython with pdb; I'll look at the docs to learn how. I do
> use winpdb on the application.

If you type %pdb *before* running your scripts, then any exception
that fires will automatically activate pdb.

But for a while we've had a more convenient way to access pdb, which
is the new %debug command.  At any time if you simply type %debug, the
pdb debugger will activate into the last unhandled exception.  So as
long as you don't wait too long after seeing an exception (since the
system only works with the *last* one, if you get a new exception from
a typo at the command line you lose the chance to inspect your
program), you can use it in a more fluid way than letting %pdb
forcefully activate every single time.

Cheers,

f