matplotlib-users — Discussion related to using matplotlib

[Matplotlib-users] Re: Parts of plot lagging from previous frame in animation

[Steve C. <ste...@ya...>]

> > I am unable to get matplotlib animations to work properly. Some of the data from
> > the previous frame is getting included.
I've just fixed it in CVS, it should appear in the next matplotlib
version. Or try installing from CVS if you need the fix now, and would
like to test it.

Steve

[Matplotlib-users] polyfit implementation

[Jean-Michel P. <jea...@ar...>]

Hi,

I'm having some troubles while fitting data with high order polynomials 
(typically order 6). I looked at the polyfit function in 
'matplotlib/mlab.py' and I must say I don't understand why the 
least-square problem isn't solved using the matrix multiplication 
instead of the * multiplication. Unless I misunderstood something, 
shouldn't the following line:


c = array(linear_algebra.inverse(Xt*X)*Xt*y)  # convert back to array


be rewritten like this?


c = array(matrixmultiply(matrixmultiply( 
linear_algebra.inverse(matrixmultiply(Xt,X)), Xt), y) )  # convert back 
to array


Thanks.


JM. Philippe

[Matplotlib-users] Re: Parts of plot lagging from previous frame in animation

[Joachim B H. <cj...@st...>]

Steve Chaplin <ste...@ya...>
writes:

> > > I am unable to get matplotlib animations to work properly. Some
> > > of the data from the previous frame is getting included.
> > > 
> > > This is with version 0.72. Any ideas about what is happening?
>
> I ran the script with GTKCairo and it looks fine to me.
> 
> Perhaps you are using GTKAgg which looks like it has the problem. My
> guess is that its caused by using gtk.idle_add() which results in
> asynchronous expose_event updates.

You may have something there. I tested different backends:
                                                      
These show the problem:           While these work fine:

  GtkAgg                            WX                  
  QtAgg                             WXAgg               
  CairoAgg                          GTK                 
  GtkCairo (yes, really)            TkAgg               

So for now I'll just switch to WXAgg. It's not as fast but it does the
job. Thanks!

(I'll assist, of course, in further testing if anyone wants to look 
into it)

-j.

[Matplotlib-users] Re: Matplotlib-users digest, Vol 1 #521 - 2 msgs

[Steve C. <ste...@ya...>]

On Mon, 2005-03-14 at 22:38 -0800, matplotlib-users-
re...@li... wrote:

> > I am unable to get matplotlib animations to work properly. Some of the data from
> > the previous frame is getting included.
> > 
> > I have included some example code that shows this. When draw() is called in the
> > loop, it draws the data from the previous frame for y<0.15 (ca), and from the
> > current frame for larger y. The final show() does *not* lag even if set_ydata
> > has not been called since the last draw().
> > 
> > This is with version 0.72. Any ideas about what is happening?
I ran the script with GTKCairo and it looks fine to me.

Perhaps you are using GTKAgg which looks like it has the problem. My
guess is that its caused by using gtk.idle_add() which results in
asynchronous expose_event updates.

Steve

[Matplotlib-users] cvs access is broken

[Nils W. <nw...@me...>]

cvs access is broken

cvs -z3 -d:pserver:ano...@cv...:/cvsroot/numpy co -P 
Numerical
cvs [checkout aborted]: unrecognized auth response from 
cvs.sourceforge.net: M PserverBackend::PserverBackend() Connect 
(Connection refused)

 

[Matplotlib-users] Bug in loglog plot, matplotlib 0.71 (Mac)

[Eliot R. S. <es...@in...>]

The following test program dies with an error when used with the
arguments shown -- but cutting back the argument lists by even one
element allows it to work OK.  So does taking out the hold(False).
This is with Mac OS X, Apple Python 2.3,  Matplotlib version 0.71,
  __revision__ '$Revision: 1.30 $'

--Eliot Smith, Indiana University

#------begin test program--------
from pylab import *

a =[2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 
21, 22]
at=[2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 
21]

b =[0.04, 0.06, 0.05, 0.07, 0.03, 0.07, 0.08, 0.05, 0.02, 0.07, 0.07, 
0.04, 0.06, 0.03, 0.01, 0.03, 0.01, 0.04, 0.03, 0.04, 0.04]
bt=[0.04, 0.06, 0.05, 0.07, 0.03, 0.07, 0.08, 0.05, 0.02, 0.07, 0.07, 
0.04, 0.06, 0.03, 0.01, 0.03, 0.01, 0.04, 0.03, 0.04]

print len(a), len(b)

hold(False)
figure(1)
loglog(a, b, 'bo')
show()

# this fails with
#File "/platlib/matplotlib/axes.py", line 1169, in draw
#ValueError: Cannot take log of nonpositive value

#replacing a, b in the loglog call with at, bt (lists just one
#item shorter) it no longer fails


# Mac OS X, Apple Python 2.3
# Matplotlib version 0.71
# __revision__ '$Revision: 1.30 $'

#----------end test program--------------------

[Matplotlib-users] Parts of plot lagging from previous frame in animation

[Joachim B. H. <cj...@fy...>]

I am unable to get matplotlib animations to work properly. Some of the data from
the previous frame is getting included.

I have included some example code that shows this. When draw() is called in the
loop, it draws the data from the previous frame for y<0.15 (ca), and from the
current frame for larger y. The final show() does *not* lag even if set_ydata
has not been called since the last draw().

This is with version 0.72. Any ideas about what is happening?

-- code follows

# animate increasing terms in fourier expansion of y=x
from pylab import *
from time import sleep

samples = 1000
max_k   = 3

x = arange(0.0, 1.0, 1.0/samples)

s = zeros((max_k,samples), Float)

for k in range(1,max_k):
    s[k] = s[k-1]+(-1)**(k+1)*sin(pi*x*k)/k

ion() # to force window creation
line, = plot(x, x*1.3, linewidth=1.0)
grid(True)
ioff()

for k in range(1,max_k):
    line.set_ydata(2/pi*s[k])
    title('k = '+str(k))
    draw()
    sleep(1)

show()

-- 
j

[Matplotlib-users] Still On Grid Problems...

[<and...@ti...>]

Hello NG,

    I have received a lot of good suggestions from you, so I would like
to thank everyone for previous posts. Anyway, I'm still having troubles
with Grid() (also with Matplotlib/Pylab version 0.73 RC2). If you run the=

following examples:

- wxcursor_demo.py
- embedding_in_wx2.py

There is no way to make the "g" key show the grid. It seems that this key=

is not responding, or the grid is deleted immediately after its creation,=

or it is never created.

If you run this example:

- embedding_in_wx.py

The "g" key works fine, the grid is shown/hidden when you hit this key.
I'm having the same problem in my application, I can not show the grid fo=
r
some reason, and it seems to me that these 2 problems are related.

Do you have any suggestion/pointer?

Thank you a lot.

Andrea.

Re: [Matplotlib-users] RE: matplotlib questions

[Ted D. <ted...@jp...>]

Jeez John if you're going to do this much work for a simple information 
request I may start sending you "questions" about my normal job. (thank you 
very much!)

Thanks for the code - it's going to save us a ton of time.  We're going to 
take the track2 demo and extend/refine/document it to be a function similar 
to  barh.  We'll have to think about the x data input for this function a 
little bit since it really needs to be something like

x= [ [ (start1,stop1), (start2,stop2), ... ],
      [ (start1,stop1), (start2,stop2), ... ],
      ...
    ]

which might be a little complicated for someone to set up correctly.

Thanks,
Ted

At 02:33 PM 3/11/2005, John Hunter wrote:
> >>>>> "Ted" == Ted Drain <ted...@jp...> writes:
>
>     Ted> We have some data that we'd like to plot and I'd like to know
>     Ted> if matplotlib (MPL) supports this directly (I don't think it
>     Ted> does) or where we should start looking to implement this
>     Ted> capability.
>
>All the core functionality is there already -- you just have to plug
>the pieces together.
>
>     Ted> We want to plot time intervals in a similar way to a
>     Ted> horizontal bar graph.  In this case, the data is when a
>     Ted> spacecraft is in view of a ground station.  So for a list of
>     Ted> ground stations (the y axis), we have lists of start and stop
>     Ted> times that represent the view periods.  So we need to:
>
>     Ted> - show the list of ground stations (i.e. arbitrary labels)
>     Ted> along the Y axis like you would on a bar chart.
>
>     Ted> - draw sets of rectangles at the right y location with the
>     Ted> length determined by the x data (in user controllable line
>     Ted> styles, colors, and fills).
>
>This is mostly available in barh, which by default has the left side
>of the bar at 0 but optionally allows you to specify the left as an
>array.  So you can use barh to plot intervals with the left side
>specfied by the 'left' arg and the bar width specified by the 'x' arg.
>The return value is a list of Rectangles, which you can customize (set
>the facecolor, edgecolor, edgewidth, transparency, etc).  See
>track1.py, attached below for an example.
>
>Note that you can use any mpl function with dates, as long as you set
>the tick formatters and locators correctly; this is also illustrated
>in the example code.
>
>     Ted> - optionally label the start and stop points of each interval
>     Ted> with the X value for that point (in this case a date/time).
>     Ted> Ideally, the user would have the option of specifying a
>     Ted> location relative to the bar for each end point like this
>     Ted> (none, high, mid, low):
>
>     Ted> High High |-----------| Mid | BAR | Mid |-----------| Low Low
>
>This requires you to compute the bar locations for the x, y, width,
>height coords of the rectangles.  You can then add text with
>text(x,y,s) if you have computed y to be the bottom, center or top of
>the bar.  track1.py also illustrates this; but see track2.py for
>examples of setting the horizontal and vertical alignment of the text,
>which should vary with High, Low or Mid for the best looking graphs.
>
>     Ted> I don't think I can currently do this in MPL so I'd like to
>     Ted> here ideas from John and anyone else on which classes I
>     Ted> should start looking at any suggestions on how this should
>     Ted> work.
>
>For real work, it helps to create custom classes to manage some of
>these layout details.  I did this in track2.py, which creates a custom
>class derived from Rectangle that contains two Text instances
>labelstart and labelstop.  This design makes more sense, since the
>View object knows it's left, bottom, width, height etc so it makes it
>easier to do layout.  The example shows how to use mpl connections to
>toggle labels on and off.
>
>In any case, the two mpl classes you want to study are
>matplotlib.patches.Rectangle and matplotlib.text.Text, and you may
>want to take a close look at matplotlib.axes.Axes.barh method.
>
>Sometimes it's easier to write an example than it is to explain how to
>use everything together.  If you can think of a nice way to wrap some
>of the functionality into reusable pieces, that would be great.
>
>JDH
>
>
>####################
>#  Begin track1.py #
>####################
>
>from matplotlib.dates import date2num
>from matplotlib.dates import HourLocator, DateFormatter
>from matplotlib.mlab import rand
>from matplotlib.numerix import arange
>from datetime import datetime
>from pylab import figure, show
>
>N = 7
>labels = ['S%d'%i for i in range(N)]
>colors = ('red', 'green', 'purple', 'brown', 'yellow', 'black', 'blue')
>
>t0 = date2num(datetime.now())
>start = t0 + rand(N)  # add random days in seconds
>locator = HourLocator(arange(0,24,2))  # ticks every 2 hours
>formatter = DateFormatter('%H')  # hour
>
>ylocs = arange(N)  # ylocs of the bar, arbitrary
>
>duration = rand(N)*0.2  # random durations in fraction of day
>
>fig = figure()
>ax = fig.add_subplot(111)
>ax.xaxis.set_major_formatter(formatter)
>ax.xaxis.set_major_locator(locator)
>
>height = 0.5  # the height of the bar, arbitrary
>bars = ax.barh(duration, ylocs, height=height, left=start)
>ax.set_yticks(ylocs)
>ax.set_yticklabels(labels)
>
>for bar, color in zip(bars, colors):
>     bar.set_facecolor(color)
>
># define some location arrays for labeling
>left = start
>right = left + duration
>top = ylocs + height/2.
>bottom = ylocs - height/2.
>center = ylocs
>
>
>
># label the 4th bar on top right
>ind = 3
>note = 'hi mom'
>x = right[ind]
>y = top[ind]
>ax.text(x,y,note)
>#ax.set_xlim((min(left), max(right)+2))
>ax.grid(True)
>ax.set_title('Time windows when craft visible by station')
>ax.set_xlabel('Time (h)')
>
>show()
>
>####################
>#  End track1.py   #
>####################
>
>
>####################
>#  Begin track2.py #
>####################
>
>from matplotlib.artist import Artist
>from matplotlib.dates import date2num
>from matplotlib.dates import HourLocator, DateFormatter
>from matplotlib.patches import Rectangle
>from matplotlib.mlab import rand
>from matplotlib.numerix import arange
>from datetime import datetime
>
>import pylab
>
>class View(Rectangle):
>     """
>     A view of when a craft is visible defined by a start and stop time
>     (days as float) with labeling capability.
>
>     A rectangle will be drawn
>     """
>     def __init__(self, ax, ind, station, start, stop, timefmt='%H:%M',
>                  timeloc='top', height=0.5, **kwargs):
>         """
>         ax is an axes instance -- the class will add required Artists
>         to to axes
>
>         ind is the station number for yaxis positions -- the rectangles 
> will be
>         drawn with vertical centers at ind with a height height.
>
>         station is a string label
>
>         start and stop will be the left and right side of the
>         rectangles
>         """
>         # for rects, x,y is lower left but we want ind to be the
>         # center
>         Rectangle.__init__(self, (start, ind-height/2), stop-start, 
> height, **kwargs)
>         ax.add_patch(self)
>         self.ind = ind
>         self.station = station
>
>         self.timefmt = timefmt
>         self.formatter = DateFormatter(timefmt)
>
>         self.labelstart  = ax.text(start, 0, self.formatter(start),
>                                 horizontalalignment='right')
>         self.labelstop = ax.text(stop, 0, self.formatter(stop),
>                                 horizontalalignment='left')
>
>         self.labelstart.set_visible(False)
>         self.labelstop.set_visible(False)
>         if timeloc is not None:
>             if timeloc == 'top':
>                 y = ind + height/2.
>                 valign = 'bottom'
>             elif timeloc == 'bottom':
>                 y = ind - height/2.
>                 valign = 'top'
>             elif timeloc == 'center':
>                 y = ind
>                 valign = 'center'
>
>             self.labelstart.set_visible(True)
>             self.labelstop.set_visible(True)
>
>             self.labelstart.set_y(y)
>             self.labelstop.set_y(y)
>
>             self.labelstart.set_verticalalignment(valign)
>             self.labelstop.set_verticalalignment(valign)
>
>
>
>
>N = 8
>t0 = date2num(datetime.now())
>start = t0 + rand(N)  # add random days in seconds
>locator = HourLocator(arange(0,24,2))  # ticks every 2 hours
>formatter = DateFormatter('%H')  # hour
>
>duration = rand(N)*0.2  # random durations in fraction of day
>stop = start + duration
>fig = pylab.figure()
>ax = fig.add_subplot(111)
>ax.xaxis.set_major_formatter(formatter)
>ax.xaxis.set_major_locator(locator)
>
>views = []
>for ind, x1, x2 in zip(range(1,N+1), start, stop):
>     view = View(ax, ind, 'S%d'%ind, x1, x2, timeloc='center')
>     # Now call any Rectangle function on view instance to customize rect,
>     # and any Text prop on view.labelstart and view.labelstop
>     views.append(view)
>
>
>yticks = [view.ind for view in views]
>ylabels = [view.station for view in views]
>
>ax.set_yticks(yticks)
>ax.set_yticklabels(ylabels)
>
>def toggle_labels(event):
>     if event.key != 't': return
>     toggle_labels.on = not toggle_labels.on
>     for view in views:
>         view.labelstart.set_visible(toggle_labels.on)
>         view.labelstop.set_visible(toggle_labels.on)
>     pylab.draw()
>toggle_labels.on = True
>
># use canvas.mpl_connect in API
>pylab.connect('key_press_event', toggle_labels)
>
>ax.autoscale_view()  # this is normally called by a plot command
>
>ax.set_xlim((min(start)-.1, max(stop)+.1))
>ax.set_ylim((0,N+1))
>ax.set_title("Press 't' to toggle labels")
>ax.set_xlabel('Time (hours)')
>ax.grid(True)
>pylab.show()
>
>
>####################
>#  End track2.py   #
>####################
>
>
>
>
>-------------------------------------------------------
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Ted Drain     Jet Propulsion Laboratory   ted...@jp...    

Re: [Matplotlib-users] RE: matplotlib questions

[John H. <jdh...@ac...>]

>>>>> "Ted" == Ted Drain <ted...@jp...> writes:

    Ted> We have some data that we'd like to plot and I'd like to know
    Ted> if matplotlib (MPL) supports this directly (I don't think it
    Ted> does) or where we should start looking to implement this
    Ted> capability.

All the core functionality is there already -- you just have to plug
the pieces together.

    Ted> We want to plot time intervals in a similar way to a
    Ted> horizontal bar graph.  In this case, the data is when a
    Ted> spacecraft is in view of a ground station.  So for a list of
    Ted> ground stations (the y axis), we have lists of start and stop
    Ted> times that represent the view periods.  So we need to:

    Ted> - show the list of ground stations (i.e. arbitrary labels)
    Ted> along the Y axis like you would on a bar chart.

    Ted> - draw sets of rectangles at the right y location with the
    Ted> length determined by the x data (in user controllable line
    Ted> styles, colors, and fills).

This is mostly available in barh, which by default has the left side
of the bar at 0 but optionally allows you to specify the left as an
array.  So you can use barh to plot intervals with the left side
specfied by the 'left' arg and the bar width specified by the 'x' arg.
The return value is a list of Rectangles, which you can customize (set
the facecolor, edgecolor, edgewidth, transparency, etc).  See
track1.py, attached below for an example.

Note that you can use any mpl function with dates, as long as you set
the tick formatters and locators correctly; this is also illustrated
in the example code.

    Ted> - optionally label the start and stop points of each interval
    Ted> with the X value for that point (in this case a date/time).
    Ted> Ideally, the user would have the option of specifying a
    Ted> location relative to the bar for each end point like this
    Ted> (none, high, mid, low):

    Ted> High High |-----------| Mid | BAR | Mid |-----------| Low Low

This requires you to compute the bar locations for the x, y, width,
height coords of the rectangles.  You can then add text with
text(x,y,s) if you have computed y to be the bottom, center or top of
the bar.  track1.py also illustrates this; but see track2.py for
examples of setting the horizontal and vertical alignment of the text,
which should vary with High, Low or Mid for the best looking graphs.

    Ted> I don't think I can currently do this in MPL so I'd like to
    Ted> here ideas from John and anyone else on which classes I
    Ted> should start looking at any suggestions on how this should
    Ted> work.

For real work, it helps to create custom classes to manage some of
these layout details.  I did this in track2.py, which creates a custom
class derived from Rectangle that contains two Text instances
labelstart and labelstop.  This design makes more sense, since the
View object knows it's left, bottom, width, height etc so it makes it
easier to do layout.  The example shows how to use mpl connections to
toggle labels on and off.  

In any case, the two mpl classes you want to study are
matplotlib.patches.Rectangle and matplotlib.text.Text, and you may
want to take a close look at matplotlib.axes.Axes.barh method.

Sometimes it's easier to write an example than it is to explain how to
use everything together.  If you can think of a nice way to wrap some
of the functionality into reusable pieces, that would be great.

JDH


####################
#  Begin track1.py #
####################

from matplotlib.dates import date2num
from matplotlib.dates import HourLocator, DateFormatter
from matplotlib.mlab import rand
from matplotlib.numerix import arange
from datetime import datetime
from pylab import figure, show

N = 7
labels = ['S%d'%i for i in range(N)]
colors = ('red', 'green', 'purple', 'brown', 'yellow', 'black', 'blue')

t0 = date2num(datetime.now())
start = t0 + rand(N)  # add random days in seconds
locator = HourLocator(arange(0,24,2))  # ticks every 2 hours
formatter = DateFormatter('%H')  # hour

ylocs = arange(N)  # ylocs of the bar, arbitrary

duration = rand(N)*0.2  # random durations in fraction of day

fig = figure()
ax = fig.add_subplot(111)
ax.xaxis.set_major_formatter(formatter)
ax.xaxis.set_major_locator(locator)

height = 0.5  # the height of the bar, arbitrary
bars = ax.barh(duration, ylocs, height=height, left=start)
ax.set_yticks(ylocs)
ax.set_yticklabels(labels)

for bar, color in zip(bars, colors):
    bar.set_facecolor(color)

# define some location arrays for labeling
left = start
right = left + duration
top = ylocs + height/2.
bottom = ylocs - height/2.
center = ylocs



# label the 4th bar on top right
ind = 3
note = 'hi mom'
x = right[ind]
y = top[ind]
ax.text(x,y,note)
#ax.set_xlim((min(left), max(right)+2))
ax.grid(True)
ax.set_title('Time windows when craft visible by station')
ax.set_xlabel('Time (h)')

show()

####################
#  End track1.py   #
####################


####################
#  Begin track2.py #
####################

from matplotlib.artist import Artist
from matplotlib.dates import date2num
from matplotlib.dates import HourLocator, DateFormatter
from matplotlib.patches import Rectangle
from matplotlib.mlab import rand
from matplotlib.numerix import arange
from datetime import datetime

import pylab 

class View(Rectangle):
    """
    A view of when a craft is visible defined by a start and stop time
    (days as float) with labeling capability.

    A rectangle will be drawn 
    """
    def __init__(self, ax, ind, station, start, stop, timefmt='%H:%M',
                 timeloc='top', height=0.5, **kwargs):
        """
        ax is an axes instance -- the class will add required Artists
        to to axes

        ind is the station number for yaxis positions -- the rectangles will be
        drawn with vertical centers at ind with a height height.

        station is a string label
        
        start and stop will be the left and right side of the
        rectangles 
        """
        # for rects, x,y is lower left but we want ind to be the
        # center
        Rectangle.__init__(self, (start, ind-height/2), stop-start, height, **kwargs)
        ax.add_patch(self)
        self.ind = ind
        self.station = station
        
        self.timefmt = timefmt
        self.formatter = DateFormatter(timefmt)

        self.labelstart  = ax.text(start, 0, self.formatter(start),
                                horizontalalignment='right')
        self.labelstop = ax.text(stop, 0, self.formatter(stop),
                                horizontalalignment='left')

        self.labelstart.set_visible(False)
        self.labelstop.set_visible(False)
        if timeloc is not None:
            if timeloc == 'top':
                y = ind + height/2.
                valign = 'bottom'
            elif timeloc == 'bottom':
                y = ind - height/2.
                valign = 'top'
            elif timeloc == 'center':
                y = ind
                valign = 'center'

            self.labelstart.set_visible(True)
            self.labelstop.set_visible(True)

            self.labelstart.set_y(y)
            self.labelstop.set_y(y)

            self.labelstart.set_verticalalignment(valign)
            self.labelstop.set_verticalalignment(valign)




N = 8
t0 = date2num(datetime.now())
start = t0 + rand(N)  # add random days in seconds
locator = HourLocator(arange(0,24,2))  # ticks every 2 hours
formatter = DateFormatter('%H')  # hour

duration = rand(N)*0.2  # random durations in fraction of day
stop = start + duration
fig = pylab.figure()
ax = fig.add_subplot(111)
ax.xaxis.set_major_formatter(formatter)
ax.xaxis.set_major_locator(locator)

views = []
for ind, x1, x2 in zip(range(1,N+1), start, stop):
    view = View(ax, ind, 'S%d'%ind, x1, x2, timeloc='center')
    # Now call any Rectangle function on view instance to customize rect,
    # and any Text prop on view.labelstart and view.labelstop
    views.append(view)


yticks = [view.ind for view in views]
ylabels = [view.station for view in views]

ax.set_yticks(yticks)
ax.set_yticklabels(ylabels)

def toggle_labels(event):
    if event.key != 't': return
    toggle_labels.on = not toggle_labels.on
    for view in views:
        view.labelstart.set_visible(toggle_labels.on)
        view.labelstop.set_visible(toggle_labels.on)
    pylab.draw()
toggle_labels.on = True    

# use canvas.mpl_connect in API
pylab.connect('key_press_event', toggle_labels)

ax.autoscale_view()  # this is normally called by a plot command

ax.set_xlim((min(start)-.1, max(stop)+.1))
ax.set_ylim((0,N+1))
ax.set_title("Press 't' to toggle labels")
ax.set_xlabel('Time (hours)')
ax.grid(True)
pylab.show()


####################
#  End track2.py   #
####################

Re: [Matplotlib-users] The plot symbol 'x' fails?

[Shidai L. <shi...@gm...>]

On Fri, 11 Mar 2005 14:29:19 -0500, Haibao Tang <ba...@ug...> wrote:
>  
> Greetings all, trivial problem, don't know if it's my machine problem. 
>   
> <<< plot([1,2,3],'gx') 
>   
> fails to plot the canvas. 
>   
> Py2.3 + Pylab .70 
>   
> Thanks. 

To back you up, it failed in version 7.2.1 as well.
-- 
With best wishes!
Shidai

[Matplotlib-users] RE: matplotlib questions

[Ted D. <ted...@jp...>]

We have some data that we'd like to plot and I'd like to know if matplotlib 
(MPL) supports this directly (I don't think it does) or where we should 
start looking to implement this capability.

We want to plot time intervals in a similar way to a horizontal bar 
graph.  In this case, the data is when a spacecraft is in view of a ground 
station.  So for a list of ground stations (the y axis), we have lists of 
start and stop times that represent the view periods.  So we need to:

- show the list of ground stations (i.e. arbitrary labels) along the Y axis 
like you would on a bar chart.

- draw sets of rectangles at the right y location with the length 
determined by the x data (in user controllable line styles, colors, and fills).

- optionally label the start and stop points of each interval with the X 
value for that point (in this case a date/time).  Ideally, the user would 
have the option of specifying a location relative to the bar for each end 
point like this (none, high, mid, low):

High              High
     |-----------|
Mid |    BAR    | Mid
     |-----------|
Low               Low


I don't think I can currently do this in MPL so I'd like to here ideas from 
John and anyone else on which classes I should start looking at any 
suggestions on how this should work.

Thanks,
Ted
Ted Drain     Jet Propulsion Laboratory   ted...@jp...    

[Matplotlib-users] The plot symbol 'x' fails?

[Haibao T. <ba...@ug...>]

Greetings all, trivial problem, don't know if it's my machine problem.

<<< plot([1,2,3],'gx')

fails to plot the canvas.

Py2.3 + Pylab .70

Thanks.

Re: [Matplotlib-users] Zoom problem with Polar

[John H. <jdh...@ac...>]

>>>>> "Philippe" == Philippe COLLET <kal...@ho...> writes:

    Philippe> Hi, Is it normal we can't use the zoom mode on a polar?

    Philippe> regards, Philippe

    Philippe> I'm using on Windows :/: - Pyhon 2.3 - Matplotlib 0.72 -
    Philippe> numarray 1.2.3 - pygtk 2.4.1 - GTk re 2.6.2 rc1 - GTKagg
    Philippe> as backend

This is a bug -- it shouldn't crash.  I've fixed my local tree so that
it doesn't crash (eg for the next release), but it still doesn't do
anything smart.  We haven't figured out yet how polar axes should
respond to navigation.  Last time I checked with matlab, I don't think
the mathworks has either.  If you have an informed opinion on this,
please advise.  Eg, what does it mean to zoom into a polar axes?

JDH

Re: [Matplotlib-users] bug with horizontal colorbar?

[John H. <jdh...@ac...>]

>>>>> "Humufr" == Humufr  <hu...@ya...> writes:

    Humufr>        Hi, I was trying to use colorbar and to place it
    Humufr> horizontal or vertical. I saw that I can't use the
    Humufr> horizontal bar because the scale is not taken in
    Humufr> count. Instead to have a scale between 3 and 9 (for
    Humufr> example) like I have with a vertical colorbar, I obtain a
    Humufr> scale between 0 and 1.

While I can figure these problems out on my own, it always helps if
you provide small examples that I can run on my machine that expose
the problem.

Remember the maxim: a code snippet is worth a thousand words...

JDH

Re: [Matplotlib-users] title, xlabel, ylabel in embedded Tk plot

[John H. <jdh...@ac...>]

>>>>> "Wendell" == Wendell Cropper <wcr...@uf...> writes:

    Wendell> Hi, Following the examples I have embedded a matplotlib
    Wendell> plot in a Tk canvas. I can't get the plot title and
    Wendell> xlabel to be added. I can use Tk to create text on the
    Wendell> canvas, but that isn't a very good solution. Could
    Wendell> someone show me a simple example?

If you post your code, we can show you the problem


Hint: where ax is an Axes or Subplot instance returned from 
fig.add_axes or fig.add_subplot

use one of 

    ax.set_title
    ax.set_xlabel
    ax.set_ylabel
    ax.text

See http://matplotlib.sf.net/matplotlib.axes.html

JDH

[Matplotlib-users] title, xlabel, ylabel in embedded Tk plot

[Wendell C. <wcr...@uf...>]

Hi,

Following the examples I have embedded a matplotlib plot in a Tk canvas. I
can't get the plot title and xlabel to be added. I can use Tk to create
text on the canvas, but that isn't a very good solution. Could someone show
me a simple example? 

Thanks,

Wendell Cropper


University of Florida
School of Forest Resources and Conservation
214 Newins-Ziegler
PO Box 110410
Gainesville, FL 32611-0410

352-846-0859  phone
352-392-1707  fax

wcr...@uf...

[Matplotlib-users] bug with horizontal colorbar?

[Humufr <hu...@ya...>]

       Hi,

I was trying to use colorbar and to place it horizontal or vertical. I 
saw that I can't use the horizontal bar because the scale is not taken 
in count. Instead to have a scale between 3 and 9 (for example) like I 
have with a vertical colorbar, I obtain a scale between 0 and 1.

Thanks,

N.

Re: [Matplotlib-users] xlabel and ylabel don't have the same comportment

[John H. <jdh...@ac...>]

>>>>> "Humufr" == Humufr  <hu...@ya...> writes:

    Humufr>             Hi, There are probably a bug (or I miss
    Humufr> another thing) in the ylabel, the fonts definitions is not
    Humufr> use like it is for the xlabel. The y label still small but
    Humufr> the x label is how I want it.

Yes this is a bug -- take the line in axes.Axes.set_ylabel that reads

        if fontdict is not None: self.title.update(fontdict)

and replace it with 

        if fontdict is not None: label.update(fontdict)

(oops)

    Humufr> ps: I'm using the last CVS.

This is not too informative.  Unfortunately, non-developer CVS lags
can be so long that "latest" can be any of many different versions.
Most helpful would be a revision number of the file you think is
involved in the bug

peds-pc311:~/python/projects/matplotlib> cvs status lib/matplotlib/axes.py
Enter passphrase for key '/home/jdhunter/.ssh/id_dsa':
===================================================================
File: axes.py           Status: Up-to-date
                                                                                
   Working revision:    1.81
   Repository revision: 1.81    /cvsroot/matplotlib/matplotlib/lib/matplotlib/axes.py,v

Thanks for the report!

[Matplotlib-users] Lines

[leonardo <le...@ya...>]

I'd like to draw lots of (2-point) segments (and then
lots of dots/cirles) in a Tk window (probably using
LineCollection), can you show me a tiny example? I've
found very useful the "Screenshots" page on the site.

I've tried to do for myself, but so far I've failed.
In the tutorial there is:

from matplotlib.backends.backend_agg import
RendererAgg
from matplotlib.transforms import Value
dpi = Value(72.0)
o = RendererAgg(400, 400, dpi)
gc = o.new_gc()
o.draw_lines(gc, (50, 100, 150, 200, 250), (400, 100,
300, 200, 250) )
o._renderer.write_png('saved.png')

(But it's for lines composed of many segments, and it
doesn't show the result in a window). Using
LineCollection, but this is still wrong:

from pylab import *
import matplotlib.collections as col
line1 = ((1,3),(4,6))
line2 = ((3,6),(2,1))
linest = (line1, line2)
lc = col.LineCollection(linest)
lc.show()
#show()

Thank you,
leonardo


		
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Do you Yahoo!? 
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[Matplotlib-users] Zoom problem with Polar

[Philippe C. <kal...@ho...>]

Hi,

Is it normal we can't use the zoom mode on a polar?

regards,
Philippe

I'm using on Windows :/:
- Pyhon 2.3
- Matplotlib 0.72
- numarray 1.2.3
- pygtk 2.4.1
- GTk re 2.6.2 rc1
- GTKagg as backend


>>>Traceback (most recent call last):
  File "C:\Python23\Lib\site-packages\matplotlib\backends\backend_gtk.py", 
line 158, in button_release_event
    FigureCanvasBase.button_release_event(self, x, y, event.button)
  File "C:\Python23\Lib\site-packages\matplotlib\backend_bases.py", line 
723, in button_release_event
    func(event)
  File "C:\Python23\Lib\site-packages\matplotlib\backend_bases.py", line 
1219, in release_zoom
    a.set_xlim((xmin, xmax))
  File "C:\Python23\Lib\site-packages\matplotlib\axes.py", line 2815, in 
set_xlim
    if self.transData.get_funcx().get_type()==LOG10 and min(vmin, vmax)<=0:
RuntimeError: This transformation does not support get_funcx

[Matplotlib-users] has anyone got matplotlib to work in a cgi script on Apache?

[Simon H. <sim...@jp...>]

Hi,

The code below when run from a file in the cgi-bin directory should 
generate a plot but it does not work:

#!d:/apps/Python23/python

import sys
import matplotlib
matplotlib.use('Agg')
from pylab import *

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

#print "Content-type: text/html\n\n"
#print "<html>Hello world!</html>"

print "Content-type: image/png\n\n"
print  savefig(sys.stdout)

However, it does not work and I am really struggling to get matplotlib 
to generate a plot dynamically in a cgi-script. If anyone has done this 
successfully I would really appreciate some help or a simple example. I 
am using Windows XP and Apache 2.0.53.

Many thanks,

Simon

[Matplotlib-users] xlabel and ylabel don't have the same comportment

[Humufr <hu...@ya...>]

            Hi,

There are probably a bug (or I miss another thing) in the ylabel, the 
fonts definitions is not use like it is for the xlabel. The y label 
still small but the x label is how I want it.


ps: I'm using the last CVS.



from pylab import *
fonts = {
      'color'               : 'k',
      'fontname'       : 'Courier',
      'fontsize'          : 'xx-large'
      }

xlabel(r'x',fonts)
ylabel(r'y',fonts)
show()

Re: [Matplotlib-users] Windows - Unable to import Pylab. Pb with Polar

[John H. <jdh...@ac...>]

>>>>> "Philippe" == Philippe COLLET <kal...@ho...> writes:

    Philippe> Hi, Sorry i have ever post this message in the support
    Philippe> section of matplotlib.sourceforge.net Maybe it was bad.
    Philippe> I try another time here :)

Remove site-packages/matplotlib and reinstall.  See, eg,

  http://matplotlib.sourceforge.net/faq.html#FAILURE

Hope this helps!
JDH

[Matplotlib-users] Windows - Unable to import Pylab. Pb with Polar

[Philippe C. <kal...@ho...>]

Hi,
Sorry i have ever post this message in the support section of 
matplotlib.sourceforge.net Maybe it was bad.
I try another time here :)

I have Python 2.3
Pygtk 2.4.1
gtk runtime environnement 2.6.2 rc1
I tryied with every version of Matplotlib since 0.63. Same error is 
happening: ImportError: cannot import name POLAR.

I decided to edit files:
- C:\Python23\Lib\site-packages\matplotlib\axes.py
l.36 put , NonSeparableTransformation in comment
l.37 put ,Polar in comment

- C:\Python23\Lib\site-packages\matplotlib\transforms.py
l.189 put ,Polar in comment
l.190 put , NonSeparableTransformation in comment

After that, it works well.
But i have no idea why this problem happened.
A colleague of mine hadn't to do it and it works perfectly.

Does someone have any idea?
Thanks,
Philippe

Here is the excecution of the python program with --verbose-helpful option

C:\>python "C:\Documents and Settings\cyril_2\Bureau\simple_plot.py" 
--verbose-h
elpful
matplotlib data path C:\Python23\share\matplotlib
loaded rc file C:\Python23\share\matplotlib\.matplotlibrc
matplotlib version 0.72
verbose.level helpful
interactive is True
platform is win32
numerix numarray 1.0
Traceback (most recent call last):
  File "C:\Documents and Settings\cyril_2\Bureau\simple_plot.py", line 3, in 
?
    from pylab import *
  File "C:\Python23\Lib\site-packages\pylab.py", line 1, in ?
    from matplotlib.pylab import *
  File "C:\Python23\Lib\site-packages\matplotlib\pylab.py", line 191, in ?
    from axes import Axes, PolarAxes
  File "C:\Python23\Lib\site-packages\matplotlib\axes.py", line 12, in ?