matplotlib-users Mailing List for matplotlib

On Thu, Apr 26, 2012 at 12:51 PM, willfurnass <wi...@th...> wrote:

>
> I've converted a simple MATLAB script [1] for wavelet decomposition-based
> analysis to Python.  I now want to create figures similar to [2] that
> feature five subplots in one column, with the 1st and 3rd being generated
> using 'subplot.plot' and the others being generated using
> 'subplot.imshow'.
>
> I want to find a way of scaling the  x and y axes of all subplots so that
> they're the same size on screen across all subplots.  Unfortunately I
> can't
> find any combination of 'aspect' or 'extent' that will let me do this.  I
> should note that I've added colorbars to all my image plots; the problem
> exists regardless of whether these are used.
>
> [1]
>
> http://www.mathworks.com/matlabcentral/fileexchange/18409-comparing-time-series-using-semblance-analysis
> [2] http://www.mathworks.com/matlabcentral/fx_files/18409/1/goldoil.jpg


You could try

    fig, axes = plt.subplots(nrows=5, sharex=True, sharey=True)

And then call `axes[0].plot(...)` and `axes[1].imshow(...)`. You could also
unpack the axes array and access them that way (if you prefer):

    ax0, ax1, ax2, ax3, ax4 = axes
    ax0.plot(...)

----

Hi Tony and others,

Thanks for the suggestion Tony.  It works if I remove my colour bars.
However if the colour bars are enabled (for the images on the 2nd, 4th
and 5th rows) then the image on the 5th and last row is squashed up on
the LHS of the subplot area to make room for all 3 (!) colour bars,
even though all subplots should share an x axis.  Any further
suggestions?

Also, I'm still having problems getting tick labels on ax.plot() and
ax.imshow() subplots to line up:

I create one subplot using plot(t_vec, y_vec)
I then create an image using t_vec and y_vec and display it as a second
subplot using imshow(image); the width of the image matrix is len(t_vec)
(not t_vec.max())

I am looking for a sane way of displaying the two subplots above each other
so that they are both the same width in pixels and have x tick labels at
consistent intervals (in pixels) that correspond to multiples of some value
of t.

I have tried using
ax.xaxis.set_major_formatter(ticker.FuncFormatter(xformat)) to scale the
image subplot ticks but can't get this to work in conjunction with the
setting of the tick intervals on both subplot axes using set_xticks.  Has
anyone got any suggestions?  

Regards,

Will
-- 
View this message in context: http://old.nabble.com/Set-x-axis-length-of-all-subplots-to-same-width-on-screen-tp33753799p33760460.html
Sent from the matplotlib - users mailing list archive at Nabble.com.

On Thu, Apr 26, 2012 at 12:51 PM, willfurnass <wi...@th...> wrote:

>
> I've converted a simple MATLAB script [1] for wavelet decomposition-based
> analysis to Python.  I now want to create figures similar to [2] that
> feature five subplots in one column, with the 1st and 3rd being generated
> using 'subplot.plot' and the others being generated using
> 'subplot.imshow'.
>
> I want to find a way of scaling the  x and y axes of all subplots so that
> they're the same size on screen across all subplots.  Unfortunately I
> can't
> find any combination of 'aspect' or 'extent' that will let me do this.  I
> should note that I've added colorbars to all my image plots; the problem
> exists regardless of whether these are used.
>
> [1]
>
> http://www.mathworks.com/matlabcentral/fileexchange/18409-comparing-time-series-using-semblance-analysis
> [2] http://www.mathworks.com/matlabcentral/fx_files/18409/1/goldoil.jpg


You could try

    fig, axes = plt.subplots(nrows=5, sharex=True, sharey=True)

And then call `axes[0].plot(...)` and `axes[1].imshow(...)`. You could also
unpack the axes array and access them that way (if you prefer):

    ax0, ax1, ax2, ax3, ax4 = axes
    ax0.plot(...)

----

Hi Tony and others,

Thanks for the suggestion Tony.  It works if I remove my colour bars.
However if the colour bars are enabled (for the images on the 2nd, 4th
and 5th rows) then the image on the 5th and last row is squashed up on
the LHS of the subplot area to make room for all 3 (!) colour bars,
even though all subplots should share an x axis.  Any further
suggestions?

Also, I'm still having problems getting tick labels on ax.plot() and
ax.imshow() subplots to line up:

I create one subplot using plot(t_vec, y_vec)
I then create an image using t_vec and y_vec and display it as a second
subplot using imshow(image); the width of the image matrix is len(t_vec)
(not t_vec.max())

I am looking for a sane way of displaying the two subplots above each other
so that they are both the same width in pixels and have x tick labels at
consistent intervals (in pixels) that correspond to multiples of some value
of t.

I have tried using
ax.xaxis.set_major_formatter(ticker.FuncFormatter(xformat)) to scale the
image subplot ticks but can't get this to work in conjunction with the
setting of the tick intervals on both subplot axes using set_xticks.  Has
anyone got any suggestions?  

Regards,

Will

-- 
View this message in context: http://old.nabble.com/Set-x-axis-length-of-all-subplots-to-same-width-on-screen-tp33753799p33760459.html
Sent from the matplotlib - users mailing list archive at Nabble.com.

> -----Original Message-----
> From: Ignas Anikevicius [mailto:ani...@gm...]
> Sent: Friday, April 13, 2012 4:25 PM
> To: mat...@li...
> Subject: [Matplotlib-users] Matplotlib and Cpp
> 
> Dear all,
> 
> I was wondering if it is possible to use matplotlib from C++ directly
> and I have found an example on how to do this on StackOverflow:
> 
> http://stackoverflow.com/questions/2509156/anyone-knows-a-matplotlib-
> equivalent-in-c-or-c
> 
> However, my question is about piping. Where could I find any tutorials
> on how to pipe data directly to matplotlib so that I would not need to
> right it to a file and then read it?
> 
> Also, does matplotlib benefit from usage of cython and if it does, are
> there any things I should know before just trying to compile a
> matplotlib script with cython?
> 
> All best,
> Ignas A.
> 

You're trying to solve the wrong problem.  If you want to use matplotlib to show your results this way the easiest thing to do would be to rework so that python was the driver.  i.e wrap your C++ code so that a python program called it instead of trying to call python from C++.

The better solution here is probably to abandon matplotlib and use a plotting library that has C bindings.  One example is DISLIN, but I'm sure there are others (and don't take this as a recommendation.)

Eric

On Fri, Apr 13, 2012 at 4:24 PM, Ignas Anikevicius <ani...@gm...>wrote:

> Dear all,
>
> I was wondering if it is possible to use matplotlib from C++ directly
> and I have found an example on how to do this on StackOverflow:
>
>
> http://stackoverflow.com/questions/2509156/anyone-knows-a-matplotlib-equivalent-in-c-or-c
>
>
Well, using that "method", you could interface with any python libraries in
C++, but you wouldn't be able to do anything useful.


> However, my question is about piping. Where could I find any tutorials
> on how to pipe data directly to matplotlib so that I would not need to
> right it to a file and then read it?
>
>
Not from C++, sorry.  matplotlib is primarially python with some C++ stuff
for efficiency.


> Also, does matplotlib benefit from usage of cython and if it does, are
> there any things I should know before just trying to compile a
> matplotlib script with cython?
>
>
matplotlib does not use Cython, it uses CXX for accelerating special parts
of the library.  Maybe you can use matplotlib in cython (I have never
tried), but there are no cython bindings that I am aware of for matplotlib.

Sorry I could not be of more help.

Ben Root

On Fri, Apr 27, 2012 at 10:11 AM, Francesco Montesano <
fra...@go...> wrote:

> Dear matplotlibers,
>
> I know almost nothing about mpl_toolkits (matplolib.__version__ = 1.1.0).
> >From the help of
> "mpl_toolkits.axisartist.floating_axes.FloatingSubplot", the init
> function reads
> __init__(self, fig, *args, **kwargs)
>
> In the example here
> (
> http://matplotlib.sourceforge.net/examples/axes_grid/demo_floating_axes.html
> )
> the object is initialised as
>  FloatingSubplot(fig, rect, grid_helper=grid_helper)
>
> If I take out 'grid_helper' I get this error:
> "ValueError: FloatingAxes requires grid_helper argument"
>
> In my understanding, **kwargs (like grid_helper) are optional
> arguments and I think that 'required' options do not make much sense.
> Besides its not documented in the help of the class.
>
> Could grid_helper be upgraded to *args?
>
> Cheers,
> Francesco
>
>
Francesco,

Yes and no.  In the most basic sense, the **kwargs are generally considered
as optional.  However, in some very advance python code, we use the
argument unpacking features of (*args, **kwargs) to create a more agnostic
API (duck-typing for call signatures, if you will).  Unfortunately, I don't
think we can update the call signature until we can drop python 2.x support.

The doc string you see when you look up FloatingSubplot is actually from
the class definition a few superclasses up.  If this makes no sense, you
aren't alone... The way FloatingSubplot is made is extremely convoluted and
I am still trying to wrap my head around it.  A docstring should probably
be added for the __init__ function of FloatingAxesBase so that its
constructor could be better explained.

Ben Root

Dear matplotlibers,

I know almost nothing about mpl_toolkits (matplolib.__version__ = 1.1.0).
>From the help of
"mpl_toolkits.axisartist.floating_axes.FloatingSubplot", the init
function reads
__init__(self, fig, *args, **kwargs)

In the example here
(http://matplotlib.sourceforge.net/examples/axes_grid/demo_floating_axes.html)
the object is initialised as
 FloatingSubplot(fig, rect, grid_helper=grid_helper)

If I take out 'grid_helper' I get this error:
"ValueError: FloatingAxes requires grid_helper argument"

In my understanding, **kwargs (like grid_helper) are optional
arguments and I think that 'required' options do not make much sense.
Besides its not documented in the help of the class.

Could grid_helper be upgraded to *args?

Cheers,
Francesco

Dear Nils,

I think that I've found what you need (example adapted from
http://notes.brooks.nu/2008/03/plotting-on-left-and-right-axis-simulateously-using-matplotlib-and-numpy/
)

import matplotlib.pyplot as plt
import numpy as np

#data to plot
x = np.linspace(0,5,num=100)
y = np.sinc(x)

fig   = plt.figure(figsize=(16,10))  #figure
ax    = fig.add_subplot(111)    #axis containing the figure
ax1 = fig.add_subplot(111, sharex=ax, sharey=ax, frameon=False)
#axis that shares both x and y and without frame (so ax is visible)

ax.plot(x, y)   #plot the data

ax1.xaxis.tick_top()  #show ticks on top
ax1.yaxis.tick_right()  #show ticks on the right

Now if you do any modification on the ax limits should reflect on ax1.

Might be that there is some smarter way of doing it, but if the
project is not too long and efficiency is not a problem, I think that
this example will suffice

Cheers,
Francesco

Il 27 aprile 2012 14:50, Nils Wagner <ni...@go...> ha scritto:
> Dear Francesco,
>
> Thank you for your prompt reply !
> My incomplete example is below.
>
> import matplotlib.pyplot as plt
> fig   = plt.figure(figsize=(16,10))
> ax    = fig.add_subplot(111)
> ind = np.arange(nfreq)
> yoff = np.array([0.0]*nfreq)
> for row in range(nsets):
>
>    ax.bar(ind,A[row,:],width,bottom=yoff, color=colours[row],label=elabel[row])
>    yoff = yoff + A[row,:]
>
> plt.legend(loc="upper left", bbox_to_anchor=(1,1))
> plt.xticks(ind+0.5*width,np.arange(nfreq)+1,rotation=90)
> ax.set_xlim(0.,nfreq)
> ax.set_ylim(0.,102.)
> plt.subplots_adjust(left=0.075, right=0.85, top=0.9, bottom=0.05)
> plt.show()
>
> How can I add xtick labels on the top of my figure ?
>
> Cheers,
>               Nils
>
>
> On 4/27/12, Francesco Montesano <fra...@go...> wrote:
>> Dear Nils,
>>
>> you can try to play with
>> i) ax.axis["right", "top", "bottom", "left"] and their methods (see
>> setup_axis3 here
>> http://matplotlib.sourceforge.net/examples/axes_grid/demo_floating_axes.html
>> for an example)
>> ii) twinx and twiny axes (example
>> http://matplotlib.sourceforge.net/examples/api/two_scales.html )
>>
>> The first one can be a bit confusing with orientations. Once I found
>> an explanation about it on matplotlib website, but I cannot find it
>> right now.
>> The second way creates a second axis that you probably don't need.
>>
>> Cheers,
>> Francesco
>>
>> Il 27 aprile 2012 11:48, Nils Wagner <nw...@ia...> ha
>> scritto:
>>> Hi all,
>>>
>>> I would like to add different xtick labels on the top and
>>> bottom of a figure. The number and position of the xticks
>>> is the same.
>>> How can I do that ?
>>>
>>> An example would be appreciated.
>>>
>>> Nils
>>>
>>> ------------------------------------------------------------------------------
>>> Live Security Virtual Conference
>>> Exclusive live event will cover all the ways today's security and
>>> threat landscape has changed and how IT managers can respond. Discussions
>>> will include endpoint security, mobile security and the latest in malware
>>> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
>>> _______________________________________________
>>> Matplotlib-users mailing list
>>> Mat...@li...
>>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>>



-- 
personals: mon...@ya..., mon...@ho... (messenger),
fra...@go....
work: mon...@mp...

http://picasaweb.google.it/franz.bergesund

Dear Nils,

you can try to play with
i) ax.axis["right", "top", "bottom", "left"] and their methods (see
setup_axis3 here
http://matplotlib.sourceforge.net/examples/axes_grid/demo_floating_axes.html
for an example)
ii) twinx and twiny axes (example
http://matplotlib.sourceforge.net/examples/api/two_scales.html )

The first one can be a bit confusing with orientations. Once I found
an explanation about it on matplotlib website, but I cannot find it
right now.
The second way creates a second axis that you probably don't need.

Cheers,
Francesco

Il 27 aprile 2012 11:48, Nils Wagner <nw...@ia...> ha scritto:
> Hi all,
>
> I would like to add different xtick labels on the top and
> bottom of a figure. The number and position of the xticks
> is the same.
> How can I do that ?
>
> An example would be appreciated.
>
> Nils
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

Hi all,

I would like to add different xtick labels on the top and 
bottom of a figure. The number and position of the xticks 
is the same.
How can I do that ?

An example would be appreciated.

Nils

Hello everyone,

I Have a problem. I have a graph inserted in a PyQt interface and I
want to clear it (When I click on a button).

I initialise the graph like that:

class Graph(FigureCanvas):
    def __init__(self,parent):

        self.fig = Figure()
        self.ax = self.fig.add_subplot(111)
        FigureCanvas.__init__(self, self.fig)

        self.R1, time,= [], []

        self.l_R1, = self.ax.plot([], self.R1,"-o", color = 'b',
label='R1')

        self.fig.canvas.draw()
        FigureCanvas.updateGeometry(self)


Later on the program I append values to the arrays: self.R1 and time  and I do:


self.l_R1.set_data(time, self.R1)
self.fig.canvas.draw()
FigureCanvas.updateGeometry(self)


So the values are correctly added to the Graph. My problem is I want
to clear the graph and re-initialize the arrays self.R1 and time to
empty arrays.
I've tried to create a def  activated by a button that do:

        self.R1, time,= [], []

        self.l_R1, = self.ax.plot([], self.R1,"-o", color = 'b',
label='R1')

        self.fig.canvas.draw()
        FigureCanvas.updateGeometry(self)

But no effects...


Anybody has an idea?

Thanks!

Fab