visualpython-users

[Visualpython-users] kepler.py

[Bruce S. <bas...@un...>]

Added to the contributed programs section of vpython.org: an 
illustration of Kepler's "equal area" rule for planetary orbits, by 
Peter Borcherds, University of Birmingham.

Bruce Sherwood

[Visualpython-users] Re: Visual Python on Fedora

[James R. <u32...@an...>]

>Those are the gtkglarea packages for Gtk 2, you need the ones for Gtk
>1.2.  On my system gtkglarea version 1.2.3 is what is installed, and I
>believe that is the most recent version that was produced for Gtk 1.x.
>
>HTH,
>Jonathan Brandmeyer
>
>  
>
Thanks for that, I installed version 1.2.2 (because there are Fedora 
rpms for it) and it installs and runs very well now :)

James

Re: [Visualpython-users] Visual Python on Fedora

[Jonathan B. <jbr...@ea...>]

On Thu, 2004-03-11 at 08:45, James Roper wrote:
> Hi,
> 
> Has anyone here managed to install Visual Python on Fedora?  When I run 
> the configure script, it keeps telling me that I don't have GtkGLArea 
> installed, even though I have installed the following two rpms:
> 
> gtkglarea2-1.99.0-1.i386.rpm
> gtkglarea2-devel-1.99.0-1.i386.rpm

Those are the gtkglarea packages for Gtk 2, you need the ones for Gtk
1.2.  On my system gtkglarea version 1.2.3 is what is installed, and I
believe that is the most recent version that was produced for Gtk 1.x.

HTH,
Jonathan Brandmeyer

[Visualpython-users] Visual Python on Fedora

[James R. <u32...@an...>]

Hi,

Has anyone here managed to install Visual Python on Fedora?  When I run 
the configure script, it keeps telling me that I don't have GtkGLArea 
installed, even though I have installed the following two rpms:

gtkglarea2-1.99.0-1.i386.rpm
gtkglarea2-devel-1.99.0-1.i386.rpm

Thanks,

James

[Visualpython-users] stereo property of display

[Bruce P. <bap...@te...>]

Can the stereo property be changed on the fly? It works fine when setting 
up a static scene -- but if changed during an animation (eg stonehenge.py) 
it terminates the program. I'd like to be able to allow the user to toggle 
stereo viewing while an animation is in progress.
Thanks

Bruce Peterson

Re: [Visualpython-users] What does 'visible' actually do ..

[Jonathan B. <jbr...@ea...>]

On Fri, 2004-02-20 at 02:16, Alan Littleford wrote:
> Hi all,
> 
>    Just started looking at VPython and instantly got confused by the
> reference manual (!):
> 
> In one section I read
> 
> "visible If false (0), object is not displayed; e.g. ball.visible = 0
> Use ball.visible = 1 to make the ball visible again."
> 
> Whereas in another I read
> 
> "To delete a Visual object just make it invisible: ball.visible = 0
> 
> Technical detail: If you later re-use the name ball, for example by
> creating a new object and naming it ball, Python will be free to release
> the memory used by the object formerly named ball"
> 
> So which is it? I tried a test and created a frame with a number of
> objects, walked the objects attribute setting them to invisible. When I
> looked at the objects attribute again it was empty - certainly implying
> the latter case is correct and once I set something invisible I should
> assume it is gone forever.
> 
> Is this true? How can I set something to be invisible and then make it
> visible again without having to reconstruct the object?
> 
> Tnx
> Alan

The idea is this: when an object is visible, the display that the object
is being rendered in owns at least one reference to the object.  So, as
long as you also own a reference to the object (by having it as a named
variable), it will not be deleted.

Recall that Python's garbage collection is a reference-counting system. 
When the reference count reaches zero, the object's memory is freed.

Does that help?
-Jonathan Brandmeyer

[Visualpython-users] What does 'visible' actually do ..

[Alan L. <al...@li...>]

Hi all,

   Just started looking at VPython and instantly got confused by the
reference manual (!):

In one section I read

"visible If false (0), object is not displayed; e.g. ball.visible = 0
Use ball.visible = 1 to make the ball visible again."

Whereas in another I read

"To delete a Visual object just make it invisible: ball.visible = 0

Technical detail: If you later re-use the name ball, for example by
creating a new object and naming it ball, Python will be free to release
the memory used by the object formerly named ball"

So which is it? I tried a test and created a frame with a number of
objects, walked the objects attribute setting them to invisible. When I
looked at the objects attribute again it was empty - certainly implying
the latter case is correct and once I set something invisible I should
assume it is gone forever.

Is this true? How can I set something to be invisible and then make it
visible again without having to reconstruct the object?

Tnx
Alan

---
Outgoing mail is certified Virus Free.
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Re: [Visualpython-users] invoking help under Python 2.3 on Mac OS X

[Jonathan B. <jbr...@ea...>]

On Fri, 2004-02-06 at 13:44, Joe Heafner wrote:
> Hi.
> Has anyone has any success in successfully invoking Help from inside 
> IDLE in Python 2.3 (Fink's version, installed on Mac OS X 10.3.2 using 
> Kelvin Chu's instructions)? Setting the BROWSER environment variable 
> has no visible effect. Nicholas Riley on the Pythonmac-SIG list noted a 
> bug in IDLE that mistakenly identifies the 'win' in Darwin as Microsoft 
> Windows so Python thinks it's running on Windows rather than on Darwin. 
> Is this the culprit:
> 
>      def python_docs(self, event=None):
>          if sys.platform.count('win') or sys.platform.count('nt'):
>              os.startfile(self.help_url)
>              return "break"
>          else:
>              webbrowser.open(self.help_url)
>              return "break"

The simplest workaround is to simply remove the test for the presence of
Windows, making the function:

     def python_docs(self, event=None):
         webbrowser.open(self.help_url)
         return "break"


-Jonathan Brandmeyer

[Visualpython-users] invoking help under Python 2.3 on Mac OS X

[Joe H. <hea...@ct...>]

Hi.
Has anyone has any success in successfully invoking Help from inside 
IDLE in Python 2.3 (Fink's version, installed on Mac OS X 10.3.2 using 
Kelvin Chu's instructions)? Setting the BROWSER environment variable 
has no visible effect. Nicholas Riley on the Pythonmac-SIG list noted a 
bug in IDLE that mistakenly identifies the 'win' in Darwin as Microsoft 
Windows so Python thinks it's running on Windows rather than on Darwin. 
Is this the culprit:

     def python_docs(self, event=None):
         if sys.platform.count('win') or sys.platform.count('nt'):
             os.startfile(self.help_url)
             return "break"
         else:
             webbrowser.open(self.help_url)
             return "break"

Cheers,
Joe Heafner -- Astronomy/Physics Instructor (by some definitions)

[Visualpython-users] Another graphing option

[Gary P. <gp...@ri...>]

I've been experimenting with Tkinter and Pmw (Python mega widgets) to=
=20
provide widgets to control and modify visual apps in real time. I've=
=20
also played with using Blt to display real time graphs in a Tkinter=
=20
frame. My starting point was David Anderson's Tk-Visual.py, one of th=
e=20
demos that comes with the standard visual distrubution.

I've got two-way communication going between visual and Tkinter, and=
=20
graphs running in a Tkinter frame. Get it here:

http://enigma.rider.edu/~gpajer/python.htm

We have plusses and minuses. On the plus side, we add fast graphing, =
no=20
timing glitches on Mac OSX, the large variety of control and display=
=20
widgets in Tkinter and Pmw.

On the minus side we must live with a more involved set up, learning =
to=20
use Tkinter, learning to use Blt.

It=92s not for everyone, but for those who are looking for more=20
flexibility and another graphing option: here you go.

Warning: there seems to be a Pmw.Blt bug that is preventing me from=
=20
turning off lines connecting data symbols. You'll see what I mean if =
you=20
get the demo running.

Warning: Blt is a bit of a pain to install on Windows. Try following =
the=20
instructions on my website. I wrote them from memory. When I get back=
 to=20
my Windows machine I'll check and see how good my memory was.

Good Luck,
Gary Pajer

Re: [Visualpython-users] Memory problems with gdots()

[Bruce S. <bas...@un...>]

The gdots feature is a horrible kludge, and I'm not too surprised that 
the performance is very poor. The problem is that I need to plot 
something circular or square, not elliptical or rectangular, in a window 
that typically has very different x and y scale factors. In the absence 
of an appropriate Visual object, I'm plotting a letter "o". This has 
many disadvantages, including (probably) great slowness. What is needed 
is an option on the sphere or cylinder object that says "here is the 
radius in x, make the object look circular on the screen".

Bruce Sherwood

Andrew Dougherty wrote:

> I'm running into performance and memory problems with gdots() under Linux.
> Specifically, the following program:
> 
>     from visual.graph import *
>     gdisplay()
>     funct = gcurve()
>     for t in arange(0, 100, .1):
> 	funct.plot( pos=(t, cos(t)))
> 
> completes in about 6 seconds and uses 13 Meg of memory (according to top), but
> the same program with gdots() instead of gcurve() takes about 135 seconds
> and consumes about 96 Megs of memory!
> 
> Does anyone have any idea what's up?
> 
> Thanks,
> 

[Visualpython-users] Memory problems with gdots()

[Andrew D. <dou...@la...>]

I'm running into performance and memory problems with gdots() under Linux.
Specifically, the following program:

    from visual.graph import *
    gdisplay()
    funct = gcurve()
    for t in arange(0, 100, .1):
	funct.plot( pos=(t, cos(t)))

completes in about 6 seconds and uses 13 Meg of memory (according to top), but
the same program with gdots() instead of gcurve() takes about 135 seconds
and consumes about 96 Megs of memory!

Does anyone have any idea what's up?

Thanks,

-- 
    Andy Dougherty		dou...@la...
    Dept. of Physics
    Lafayette College, Easton PA 18042

Re: [Visualpython-users] slider

[Arnd B. <arn...@we...>]

Hi,

On Wed, 28 Jan 2004, Andrew Dougherty wrote:
> On Tue, 27 Jan 2004, P H Borcherds wrote:
[...]
> > I have increased the number of points displayed in the poincare section to
> > 400 (see attached jpeg: 40 points is not sufficient).
>
> That, of course, depends both on what you're trying to do and on the speed
> of your computer (and/or the patience of your users!).  In my case, the
> students were supposed to be exploring period-doubling, so 40 points was
> plenty.  Obviously for more interesting behavior, more would usually be
> better.

I am not sure if this is of any help, but we have
been using scipy.xplt for things like this.
An example is
http://www.comp-phys.tu-dresden.de/cp2003/uebung3/standardabbildung.py
where we use the standard map (think of this as the Poincare map
of something more complicated) - sorry the doc inside is
in German.
In this example the points are _not_ shown dynamically (i.e. not one after
another) but this can be achieved as well.
(Notice that, as with most of the newer plotting tools,
all the points are kept in memory, but our students had
no basic problems running this on their machines (both Linux/Windows)
at home).
Of course scipy (www.scipy.org) is a pretty big package,
but personally I think it is really worth installing ...

Arnd

Re: [Visualpython-users] slider

[Andrew D. <dou...@la...>]

On Tue, 27 Jan 2004, P H Borcherds wrote:

> Dear all
>
> I have downloaded and run Andy Dougherty's program. It is helpful to have an
> example like this to see how to put several windows on the screen

Thanks.  I don't pretend it's "good" or "right" -- it's just the first
thing that worked for me :-).

> I have increased the number of points displayed in the poincare section to
> 400 (see attached jpeg: 40 points is not sufficient).

That, of course, depends both on what you're trying to do and on the speed
of your computer (and/or the patience of your users!).  In my case, the
students were supposed to be exploring period-doubling, so 40 points was
plenty.  Obviously for more interesting behavior, more would usually be
better.

> On my computer (PC with tft screen) the DISPLAY of the pendulum is very
> jerky: Can anyone offer help on this?

Only the observation that I see such behavior (or much worse, a failure to
even run) on slower machines or on machines with strained resources.  It
won't work at all on any of my Linux systems (though none of them are
blazingly fast) nor on some of the slower windows systems around here.

This is a general problem I've observed with many programs using gdots.
I tend not to see it so much using gcurve.  I also tend to see such
problems when using more than one window, especially on my Linux systems.
I vaguely suspect that there is a buried race condition somewhere in the
inter-thread communications, and also that there's something amiss with
the gdots() representation.  However, I haven't been able to track it down
further.  I may have some oppotunities this spring since I'm using vpython
in a course.

-- 
    Andy Dougherty		dou...@la...

Re: [Visualpython-users] scene.select() active screen

[Bruce S. <bas...@un...>]

Hmm. Although every Visual object has an attribute "display" (so that if 
you knew an object you could know what display it was in), there does 
indeed seem to be a gap in the Visual machinery, in that I too see no 
way to determine what graphics window the mouse is in.

Bruce Sherwood

CHAPMAN, RICHARD wrote:

> hi
>  
> is there a function to obtain what the current active screen is, the
> screen that the user is currently entering input into. if you have no
> idea what scenes the "users" might have created?
>  
> example application: say i wanted to animate the drawing of a line
> where the user just drags the mouse.  but i do not want to have to
> pass into that function what screen is currently being used. i would
> like the line function to detect what screen the user is currently
> using.
>  
> thanks 
>  
> rich
> 
> 
> -------------------------------------------------------
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> See the breadth of Eclipse activity. February 3-5 in Anaheim, CA.
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> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users

Re: [Visualpython-users] minimized display zaps VPython

[Bruce S. <bas...@un...>]

I don't see this behavior on Windows, nor have I ever seen it on 
Windows. I have no clue as to why you're seeing this.

Bruce Sherwood

Bruce Peterson wrote:

> Under windows, when a VPython display window is minimized (using the 
> window minimize button) and the un-minimized, when the window 
> re-appears, all Vpython objects are gone. (no error messages, just no 
> visuals)
> First -- is this expected behavior? and what can be done about it. I can 
> see how VPython may have difficulty updating a minimized window scene -- 
> could smarts be added to freeze updating when the window is minimized? 
> or alternately could window minimization be trapped so that full 
> minimization is not allowed.
> 
> Bruce Peterson
> 
> 
> 
> -------------------------------------------------------
> The SF.Net email is sponsored by EclipseCon 2004
> Premiere Conference on Open Tools Development and Integration
> See the breadth of Eclipse activity. February 3-5 in Anaheim, CA.
> http://www.eclipsecon.org/osdn
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users

Re: [Visualpython-users] slider

[P H B. <P.H...@bh...>]

Dear all

I have downloaded and run Andy Dougherty's program. It is helpful to have an
example like this to see how to put several windows on the screen

I have increased the number of points displayed in the poincare section to
400 (see attached jpeg: 40 points is not sufficient).

On my computer (PC with tft screen) the DISPLAY of the pendulum is very
jerky: Can anyone offer help on this?

Regards

Peter Borcherds



> 
>   http://www.lafayette.edu/~doughera/other/python/examples/drivenpend.py
> 
-- 
Dr P H Borcherds	|<mailto:P.H...@bh...>
			|phone 	0044 (0)121 475 3029

[Visualpython-users] ALERT - GroupShield ticket number OA152_1075215622_UPS_1 was gen erated

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[Visualpython-users] minimized display zaps VPython

[Bruce P. <bap...@te...>]

Under windows, when a VPython display window is minimized (using the window 
minimize button) and the un-minimized, when the window re-appears, all 
Vpython objects are gone. (no error messages, just no visuals)
First -- is this expected behavior? and what can be done about it. I can 
see how VPython may have difficulty updating a minimized window scene -- 
could smarts be added to freeze updating when the window is minimized? or 
alternately could window minimization be trapped so that full minimization 
is not allowed.

Bruce Peterson

Re: [Visualpython-users] vpython fink package for Mac OSX 10.3

[Jonathan B. <jbr...@ea...>]

On Sun, 2004-01-25 at 18:22, Martin Costabel wrote:
> Jonathan Brandmeyer wrote:
> 
> 
> > Excellent, I got it.  I have a build going as I write this on a 10.2 box
> > with Python 2.2 and an Apple-distributed GCC 3.1.
> 
> Yes, I found now that the error I am seeing comes from using gcc-3.3 
> which is the standard on OSX 10.3. It goes away when I use gcc-3.1. It 
> seems that the CXX library does not work with gcc-3.3. This is really 
> weird, because all these things are in the end linked with the python2.3 
> executable which was compiled with gcc-3.3, and C++-compiled binaries 
> are, in general, not compatible between gcc-3.1 and gcc-3.3.

It isn't an issue because the interface between cvisualmodule.so and
Python(.exe) is exclusively C-based, and the C ABI did not change
between those releases.  The only conflict would arise if you linked
some other shared object to cvisualmodule.so, which I can't imagine
anyone doing.

> Anyway, if no solution is found to make the CXX stuff compatible with 
> gcc-3.3, I can require that the package is built with gcc-3.1, crossing 
> fingers that this will not break other things.
> 

> > cvisual/Makefile is totally insensitive to the DESTDIR variable, exactly
> > why is it needed?  Is the makefile not picking up on the value of
> > 'prefix' for some reason?
> 
> It is, but the fink build process is like with debian or rpm: You don't 
> install to the final destination, but to some build-root from which the 
> package is then created. Thus the prefix is set to /sw (%p in the info 
> file), but the make install has to install into 
> /sw/src/root-visual-py23-2.1.9-1/sw/
> 
> Hence the need for the DESTDIR variable which is respected in all 
> subdirectories except cvisual. cvisual/Makefile installs the vpython 
> script directly into /sw/bin which is illegal, because in this way it 
> does not get into the package.

OK.  I'll put this change into CVS.

> 
> > With the changes that your patch makes to OSX_SORULE, the link step
> > fails with many undefined references to functions defined in the Python
> > executable itself.
> 
> The "-bundle_loader $PYTHON" flag takes care of this. It tells ld to 
> look for undefined symbols in the python executable. There was just a 
> syntax error: -bundle_loader doesn't take a "=" sign. I removed the 
> -flat_namespace, because the python executable is compiled as a 
> two_level binary, but I guess this doesn't make much difference.
> In any case, it compiled OK for me, both with gcc-3.3 and with gcc-3.1.

It was the "=" sign that was the problem, I didn't see notice that
before.  I'll put this into CVS as well.

> > Just exactly what does that sed script do?  I've never used sed.
> 
> This is something completely unimportant. I wanted to have something 
> other than the license.txt in the doc directory. For every fink package 
> there is a doc directory in /sw/share/doc, in this case 
> /sw/share/doc/visual-py23. I took the docs/index.html to put there, 
> renamed to visual.html, and the sed changes the links in that file so 
> that they point to the other local vpython html files in 
> /sw/lib/python2.3/site-packages/visual/docs. I don't know enough about 
> the inner workings of vpython to see whether the latter need to remain 
> in the site-packages/visual/docs directory or whether they could be 
> moved to /sw/share/doc/visual, so I let them where they were installed 
> by default.

No, they don't need to be in any place special.  We did that for a
distribution-independent location, and I fully expect distributors to
rearrange file locations as required to satisfy the distribution's
policies.

> > What command do you execute to build the package? (eg, the counterpart
> > to dpkg-buildpackage in Debian).
> 
> The command is simply "fink install visual-py23". Fink actually creates 
> a *.deb package and then uses dpkg to install it at its final 
> destination. If one wants to build only the deb package without 
> isntallation, the command is "fink build visual-py23".
> 
> The package will first go into the unstable tree, so that fink users 
> will have to activate this. After some time, it will migrate to the 
> stable tree, and in this case it can then become part of Fink's binary 
> distribution. When this is achieved, Fink users can use "apt-get install 
> visual-py23" to get the precompiled binary directly.
> 
> > visual/Makefile byte-compiles site-packages/visual/*.py already, why is
> > the post-install script doing this as well?
> 
> I saw that the *.pyc files have the buildroot directory hardwired inside 
> and suspected that this could have something to do with my error, so I 
> compiled them a second time after they were installed at their final 
> place. But I think this is useless, after all. OK, while I wrote this, I 
> compiled it again without this PostInstScript, and the ball is still 
> bouncing, so I guess I'll remove this part.

If the *.pyc files have something wrong with them, then they would
normally be recompiled on use, but since normal users don't have access
to that directory, it is silently ignored and the interpreter will use
the plain .py files instead.  The only consequence would be a slightly
slower module loading time.  So, if there is a problem, you should
probably go ahead and re-run py-compile on those files.

> 
> Another question: I read Kelvin Chu's installation instructions, and he 
> says that gdbm3 is needed, too. Is this true? I don't see anything 
> gdbm-related in the compile log.

Is that the GNU Database Manager?  AFAIK it isn't needed.

Thanks again,
Jonathan Brandmeyer

Re: [Visualpython-users] vpython fink package for Mac OSX 10.3

[Martin C. <cos...@wa...>]

Gary Pajer wrote:
[]
> (Mine's already working on 10.2 ... but you are doing a great thing for
> future users.

OK guys, I have put the visual-py23 package into the Fink 10.3/unstable 
and 10.2-gcc3.3/unstable trees (Yes, 10.2-gcc3.3, although the package 
requires to be built with gcc-3.1, but the old 10.2 tree is not 
supported any more). They should show up on the next selfupdate soon. I 
let you in the later timezones give them a hard time while I sleep (1:30 
am here now).

-- 
Martin

Re: [Visualpython-users] vpython fink package for Mac OSX 10.3

[Aaron T. <ti...@ma...>]

Martin,

I also want to say "thank you" for creating the fink package. I use 
10.2, and will probably upgrade to 10.3 sometime this summer. I 
presently use visual, but it's not even the latest version. I'm too 
nervous to attempt the upgrade until I have time to troubleshoot. A 
Fink package will be welcomed indeed.

Thank you!

AT


> (Mine's already working on 10.2 ... but you are doing a great thing for
> future users.
> You deserve a medal.)

Re: [Visualpython-users] vpython fink package for Mac OSX 10.3

[Martin C. <cos...@wa...>]

Gary Pajer wrote:
[]
> I'm happy that Jonathan has been having success building on 10.2.  I
> encourage you again to ensure that it works in 10.2.

It works on 10.2 in the same way as on 10.3, that is, it works when 
compiled with gcc-3.1 and doesn't when compiled with gcc-3.3.

-- 
Martin

Re: [Visualpython-users] vpython fink package for Mac OSX 10.3

[Gary P. <pa...@in...>]

> Yes, I found now that the error I am seeing comes from using gcc-3.3
> which is the standard on OSX 10.3. It goes away when I use gcc-3.1. It
> seems that the CXX library does not work with gcc-3.3. This is really
> weird, because all these things are in the end linked with the python2.3
> executable which was compiled with gcc-3.3, and C++-compiled binaries
> are, in general, not compatible between gcc-3.1 and gcc-3.3.

FYI, these are the kinds of problems that have popped up on the fink
discussion board, and have been giving me agita about upgrading to 10.3.

I'm happy that Jonathan has been having success building on 10.2.  I
encourage you again to ensure that it works in 10.2.

(Mine's already working on 10.2 ... but you are doing a great thing for
future users.
You deserve a medal.)

-Gary