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Hi,

that's true... I have been playing with maxima.

I define the function

F(x,y,z):=38244.74787*%pi*(x^2+y^2+z^2)^0.125
        +1615.975261*%pi*z^2/(x^2+y^2+z^2)^0.875
        +(-1292.78021)*%pi*z^2/((x^2+y^2+z^2)^0.875*(1+y^2/x^2))
        +1292.78021*%pi*(x^2+y^2+z^2)^0.125/(1+y^2/x^2);

then I factor it

factor(F(x,y,z)=0);

Multiply it by the denominator

% * 32365900000*(z^2+y^2+x^2)^(7/8);

divide by pi


% / %pi;


So that  F(x,y,z)=0 is equivalent to

1290128178785633*z^2+1237825685085633*y^2+1279667680084472*x^2=0

The only real solution is 0,0,0,


But then I try to define a cube centered at the origin which contains
at least a part of the surface:

load(draw);
n: 10$
draw3d(
    enhanced3d = true,
    implicit(
        F(x,y,z) = k,
        x,-n,n,y,-n,n,z,-n,n));

Since it's taking huge values even for small x,y,z, one has to use
either very small n or very large k but even in that case I get
draw3d (implicit): non real value

How could I check the same in matplotlib?

Am I missing something? Maybe this is a bug in maxima...

Any help will be appreciated!

On Tue, Jan 22, 2013 at 3:29 PM, Benjamin Root <ben...@ou...> wrote:
>
>
> On Mon, Jan 21, 2013 at 8:06 PM, Pau <vim...@go...> wrote:
>>
>> Hi,
>>
>> I am somehow new to matplotlib and I am trying to plot this function of x
>> ,y ,z
>>
>> F(x,y,z)=
>> 38244.74787*Pi*(x^2+y^2+z^2)^.125+1615.975261*Pi*z^2/(x^2+y^2+z^2)^.875-1292.780210*Pi*z^2/((x^2+y^2+z^2)^.875*(1+y^2/x^2))+1292.78*Pi*(x^2+y^2+z^2)^.125/(1+y^2/x^2)
>>
>> in a similar way as
>>
>> http://matplotlib.org/mpl_examples/mplot3d/contour3d_demo3.hires.png
>>
>> The code is
>> http://matplotlib.org/mpl_examples/mplot3d/contour3d_demo3.py
>>
>> But I have no idea where to start...
>>
>> some help would be appreciated...
>>
>> thanks
>>
>
> The reason you are having difficulty coming up with a way to plot this is
> because you have 3 input dimensions, and 1 output dimension that you wish to
> plot.  If you were to plot this in 3D space, it would have to be done as
> F(x,y,z) as a colored "mist" in the domain of (x,y,z).  While a "mist" can't
> be done in mplot3d, you could plot out scatter points to emulate this.  One
> could also use contourf3d(..., zdir='z', offset=...) to create slices of the
> filled contours, similar to this example:
>
> http://matplotlib.org/examples/mplot3d/contourf3d_demo2.html
>
> Now, if the domain of (x,y,z) can be parameterized as a surface (i.e., a
> sphere or a cylinder), then you are looking to do an image of F(x,y,z)
> plotted on that surface, which is a little bit difficult, but also do-able
> using the plot_surface() function.
>
> Cheers!
> Ben Root
>

Hi,

I often use mpl interactively (in ipython --pylab) to plot 2d data on
basemaps using pcolormesh. When moving the mouse over the map, I can see
x,y coordinates being displayed in the bottom right of the plot window.
What would be more interesting for me is the value of the pcolomesh'ed
data variable at the point where the mouse cursor is.

Any way I can get this information?

Cheers, Andreas.

Dear all

  Has anyone attempted to use matplotlib within a mac (cocoa) application
before (e.g. using PyRun_SimpleFile or PyRun_SimpleString)?  I can
successfully get get a plot to appear in a new window but when closing this
window the entire application quits without any error.  Looking at the
source code, the macosx backend seems to kill the currently running NSApp.
 Is there a reason for this and is there any way around it?

Many thanks!

2013/2/1 Benjamin Root <ben...@ou...>

>
>
> On Fri, Feb 1, 2013 at 11:04 AM, Jeff Layton <lay...@at...> wrote:
>
>> Good morning,
>>
>> I'm been using matplotlib for a while but it's always been very
>> simple plots (hey - I'm a simple person). I have a need for some
>> "fancier" plots using subplots.
>>
>> I want to have 3 charts one above the other with a single set of
>> x-axis labels on the bottom subplot that works for all three charts.
>> I'd also like to put a legend outside the set of three charts - either
>> to the top right or horizontally along the bottom.
>>
>> I've been reading a number of links and nothing really works.
>> Most everything is around pylab and I'm using just straight
>> matploblib. I hate to say it, but I need to have the solution and
>> I'm looking for some newbie help. One of the frustrating aspects
>> is I need to make sure it works for version 0.91 :(
>>
>> I'm attaching a simple example script that shows the plots
>> as I currently have achieved them. Apologies for any bad coding.
>> Just in case the attachment doesn't make it through the code is
>> below.
>>
>> Thanks!
>>
>> Jeff
>>
>>
>>
> I don't know when it was introduced, but ax.label_outer() (called on each
> axes object) can help you with the axis labeling.  If that works, we can
> then tackle legend placement.
>

if it does not work should be possible to do for ax1 and ax2

[t.set_visible(False) for t in ax.get_xticklabels()]

Francesco



> Ben Root
>
>
>
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>
>

On Fri, Feb 1, 2013 at 11:04 AM, Jeff Layton <lay...@at...> wrote:

> Good morning,
>
> I'm been using matplotlib for a while but it's always been very
> simple plots (hey - I'm a simple person). I have a need for some
> "fancier" plots using subplots.
>
> I want to have 3 charts one above the other with a single set of
> x-axis labels on the bottom subplot that works for all three charts.
> I'd also like to put a legend outside the set of three charts - either
> to the top right or horizontally along the bottom.
>
> I've been reading a number of links and nothing really works.
> Most everything is around pylab and I'm using just straight
> matploblib. I hate to say it, but I need to have the solution and
> I'm looking for some newbie help. One of the frustrating aspects
> is I need to make sure it works for version 0.91 :(
>
> I'm attaching a simple example script that shows the plots
> as I currently have achieved them. Apologies for any bad coding.
> Just in case the attachment doesn't make it through the code is
> below.
>
> Thanks!
>
> Jeff
>
>
>
I don't know when it was introduced, but ax.label_outer() (called on each
axes object) can help you with the axis labeling.  If that works, we can
then tackle legend placement.

Ben Root

Good morning,

I'm been using matplotlib for a while but it's always been very
simple plots (hey - I'm a simple person). I have a need for some
"fancier" plots using subplots.

I want to have 3 charts one above the other with a single set of
x-axis labels on the bottom subplot that works for all three charts.
I'd also like to put a legend outside the set of three charts - either
to the top right or horizontally along the bottom.

I've been reading a number of links and nothing really works.
Most everything is around pylab and I'm using just straight
matploblib. I hate to say it, but I need to have the solution and
I'm looking for some newbie help. One of the frustrating aspects
is I need to make sure it works for version 0.91 :(

I'm attaching a simple example script that shows the plots
as I currently have achieved them. Apologies for any bad coding.
Just in case the attachment doesn't make it through the code is
below.

Thanks!

Jeff




#!/usr/bin/python
#

import matplotlib.pyplot as plt;

if __name__ == '__main__':

    x=[0.0, 1.0, 2.0, 3.0, 4.0];
    y1 = [11.97, 1.01, 2.97, 1.0, 1.01];
    y2 = [3.55, 1.01, 3.96, 1.0, 0.0];
    y3 = [0.29, 0.0, 0.0, 0.0, 0.0];

    fig = plt.figure();
    ax1 = fig.add_subplot(311);
    ax2 = fig.add_subplot(312, sharex=ax1);
    ax3 = fig.add_subplot(313, sharex=ax1);

    ax1.plot(x, y1, "ro-");
    ax2.plot(x, y2, "bo-");
    ax3.plot(x, y3, "go-");

    ax1.grid();
    ax2.grid();
    ax3.grid();

    plt.show();

# end main

FancyArrowPatch behaves quite differently from normal patches.
Most importantly, the path must be reevaluated during the drawing time, so
a normal PatchCollection, which evaluate the paths during the instance
creation, won't work. i.e., you need a new Collection class.

Below is a very incomplete implementation of FancyArrowPatchCollection,
just for a demonstration purpose. And I recommend you to open a wishlist
ticket at the issue tracker (https://github.com/matplotlib/matplotlib/issues
).

Regards,

-JJ


class FancyArrowPatchCollection(PatchCollection):
    def set_paths(self, patches):
        self._patches = patches

    def get_paths(self):
        paths = []
        for p in self._patches:
            p.set_transform(self.get_transform())
            _path, fillable = p.get_path_in_displaycoord()
            paths.extend(_path)
        return paths

    def _prepare_points(self):
        import matplotlib.transforms as mtransforms
        transform, transOffset, offsets, paths =
PatchCollection._prepare_points(self)
        return mtransforms.IdentityTransform(), transOffset, offsets, paths




On Thu, Jan 31, 2013 at 6:33 AM, Skipper Seabold <jss...@gm...>wrote:

> Hi,
>
> Trying to figure out why these two do not create the same plot. Bug or
> user error?
>
> import matplotlib.pyplot as plt
> from matplotlib.patches import FancyArrowPatch
> from matplotlib.collections import PatchCollection
>
> def correct_patch(pos):
>     fig, ax = plt.subplots()
>     for src, dst in pos:
>         arrow = FancyArrowPatch(posA=src, posB=dst,
>                                 color='k', arrowstyle='-|>',
>                                 mutation_scale=30, connectionstyle="arc3")
>         ax.add_patch(arrow)
>     return fig
>
> def patch_collection_problem(pos):
>     fig, ax = plt.subplots()
>     pos = [[(.5, .5), (.25, .25)],
>            [(.1, .5), (.2, .75)]]
>     arrows = []
>     for src, dst in pos:
>         arrows.append(FancyArrowPatch(posA=src, posB=dst,
>                                 color='k', arrowstyle='-|>',
>                                 mutation_scale=30, connectionstyle="arc3"))
>     collection = PatchCollection(arrows, match_original=True)
>
>     ax.add_collection(collection, autolim=False)
>     return fig
>
> pos = [[(.5, .5), (.25, .25)],
>           [(.1, .5), (.2, .75)]]
>
> correct_patch(pos)
> patch_collection_problem(pos)
>
>
> ------------------------------------------------------------------------------
> Everyone hates slow websites. So do we.
> Make your web apps faster with AppDynamics
> Download AppDynamics Lite for free today:
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> _______________________________________________
> Matplotlib-users mailing list
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> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>
>