visualpython-users

Re: [Visualpython-users] SConstruct

[K.-Michael A. <kmi...@gm...>]

On 2012-04-19 16:02:17 +0000, Bruce Sherwood said:

> SConstruct was just an experience many years ago by Jonathan
> Brandmeyer and is now irrelevant.

Thanks, I am creating a cleaned up git branch ONLY for an Mac_EPD 
build. Thanks to git this can live totally independent from anything 
else, so I am kicking everything out that's not required anymore.

> 
> There are three quite different build procedures, for Windows, Mac,
> and Linux, each of them detailed in VCBuild/VCBuild.txt, MAC-OSX.txt,
> and INSTALL.txt, respectively. And in the Linux case, in addition to
> the complex autoconfigure machinery currently used to build the Linux
> tarball posted at vpython.org, there is a simple makefile in src/gtk2
> intended to give a sense of a basic build stripped to its essentials
> and aimed specifically at Ubuntu.

That was a good tip, thanks.
That leaves me puzzled, how the makefile in src/mac actually can work? 
My makefile-foo is a bit rusty, but I am missing something like this 
line from the src/gtk2/makefile:

%.o: %.cpp
	$(CXX) $(CVISUAL_CPPFLAGS) $(CVISUAL_CXXFLAGS) -MMD -MF $*.d -MT "$*.d 
$*.lo" -c -o $@ $<

in the src/mac version, that clearly makes use of the previously 
defined flags and tells the make system how to create all the objects.

Still it seems the system gets the CXXFLAGS in the Mac's makefile 
somehow at build time, because when I comment them out, the errors I 
get look different.
Just really puzzling…

Michael


> 
> Bruce Sherwood
> 
> On Thu, Apr 19, 2012 at 9:47 AM, K.-Michael Aye 
> <kmi...@gm...> wrote:
>> Dear all,
>> 
>> I see that somebody played with SConstruct in the sources.
>> Before I spend too much time on digging in there: What is it being used
>> for? Packaging for installations? Or also the building process? If also
>> building, only for Win and Linux, or also for Mac?
>> 
>> TIA,
>> 
>> Michael
> 
> ------------------------------------------------------------------------------
> For Developers, A Lot Can Happen In A Second.
> Boundary is the first to Know...and Tell You.
> Monitor Your Applications in Ultra-Fine Resolution. Try it FREE!
> http://p.sf.net/sfu/Boundary-d2dvs2

Re: [Visualpython-users] SConstruct

[Bruce S. <Bru...@nc...>]

SConstruct was just an experience many years ago by Jonathan
Brandmeyer and is now irrelevant.

There are three quite different build procedures, for Windows, Mac,
and Linux, each of them detailed in VCBuild/VCBuild.txt, MAC-OSX.txt,
and INSTALL.txt, respectively. And in the Linux case, in addition to
the complex autoconfigure machinery currently used to build the Linux
tarball posted at vpython.org, there is a simple makefile in src/gtk2
intended to give a sense of a basic build stripped to its essentials
and aimed specifically at Ubuntu.

Bruce Sherwood

On Thu, Apr 19, 2012 at 9:47 AM, K.-Michael Aye <kmi...@gm...> wrote:
> Dear all,
>
> I see that somebody played with SConstruct in the sources.
> Before I spend too much time on digging in there: What is it being used
> for? Packaging for installations? Or also the building process? If also
> building, only for Win and Linux, or also for Mac?
>
> TIA,
>
> Michael

[Visualpython-users] SConstruct

[K.-Michael A. <kmi...@gm...>]

Dear all,

I see that somebody played with SConstruct in the sources.
Before I spend too much time on digging in there: What is it being used 
for? Packaging for installations? Or also the building process? If also 
building, only for Win and Linux, or also for Mac?

TIA,

Michael

[Visualpython-users] g++-4.0 for Mac?

[K.-Michael A. <kmi...@gm...>]

Dear all,

in my efforts to build vpython for EPD I am currently at the hurdle of 
not having an g++-4.0 for Mac available.
Astonishingly, Macport's apple-gcc40 only provides gcc but no g++ ?
Would anybody know how to get a g++-4.0 installed on an up-to-date Lion Mac?

Best regards,
Michael

[Visualpython-users] New Mac installers reposted

[Bruce S. <Bru...@nc...>]

I discovered to my chagrin that my Mac hard drive had errors and had
to be repaired, and the VPython 5.73 installers for the Mac (for
Python 2.7 and Python 3.2) had to be rebuilt. These have now been
posted to the Mac download page at vpython.org.

Bruce Sherwood

Re: [Visualpython-users] covering a sphere with patches

[Anton S. <br...@po...>]

On 2012-4-17 21:26, Anton Sherwood wrote:
> http://maths.anu.edu.au/~leopardi/Leopardi-Sphere-PhD-Thesis.pdf (5.8MB)
> gives a partition of the sphere into relatively compact "rectangles" of
> equal area.  ...

And now looking at Leopardi's homepage I see that he's made a Matlab 
'toolbox' for the algo: http://eqsp.sourceforge.net/ -- maybe looking at 
the source will be useful even without Matlab.

-- 
Anton Sherwood *\\* www.bendwavy.org *\\* www.zazzle.com/tamfang

Re: [Visualpython-users] covering a sphere with patches

[Anton S. <br...@po...>]

On 2012-4-17 10:12, Joe Heafner wrote:
> Can someone direct me to an algorithm for covering a sphere with
> patches of equal area for the purposes of illustrating the surface
> integral in Gauss's law? I've tried three so far and can't get
> good results. The problem is mostly with the poles and in the
> foreshortening of the patches near the poles. Is there a standard
> algorithm for this somewhere? Rectangular surfaces are easy.

The key thing to remember is that equally spaced parallel planes cut the 
sphere into bands of equal area.

http://maths.anu.edu.au/~leopardi/Leopardi-Sphere-PhD-Thesis.pdf (5.8MB) 
gives a partition of the sphere into relatively compact "rectangles" of 
equal area.  I think it even covers spheres of higher dimension.

-- 
Anton Sherwood *\\* www.bendwavy.org *\\* www.zazzle.com/tamfang

Re: [Visualpython-users] covering a sphere with patches

[Kevin K. <ka...@so...>]

Try 
http://www.cse.cuhk.edu.hk/~ttwong/papers/udpoint/udpoints.html
http://local.wasp.uwa.edu.au/~pbourke/geometry/spherepoints/
http://mathforum.org/kb/thread.jspa?forumID=13&threadID=1248382&messageID=3985254
http://www.mathworks.com/matlabcentral/newsreader/view_thread/21747

Many of these use random points with a uniform distribution on the
surface of the sphere, but at least one of them was deterministic.
Most of the surface integral calculations I've seen have used sample
points, rather than patches.

Re: [Visualpython-users] covering a sphere with patches

[kirby u. <kir...@gm...>]

> OK, I know, I forgot the octahedron...
> Then, the subdivision of the faces you obtain into smaller ones should not
> be too difficult.
>
> Jerzy Karczmarczuk
>

The triangles of a geodesic sphere e.g. subdivided icosahedron, are
not equal area though, not exactly.  Maybe exactness is not critical.

There are lots of reflections so don't have to compute a full sphere.
1/120th is a common patch to reflect around, based on rhombic
triacontahedron breaking into 4 triangles.

There's a book coming out any day now, 'Divided Spheres' by Edward
Popko that should have a lot of good info.

Kirby

http://www.amazon.com/Divided-Spheres-Geodesics-Orderly-Subdivision/dp/1466504293
> PS. People who want always have one nice mathematical formula for some
> spherical problems too often forget that it is not necessary to have two
> singularities at the poles, just one is possible with the stereographic
> projection. But the distortions are awful...
>
>
> ------------------------------------------------------------------------------
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>

Re: [Visualpython-users] covering a sphere with patches

[Jerzy K. <jer...@un...>]

Joe Heafner:
> Can someone direct me to an algorithm for covering a sphere with patches of equal area for the purposes of illustrating the surface integral in Gauss's law? I've tried three so far and can't get good results. The problem is mostly with the poles and in the foreshortening of the patches near the poles. Is there a standard algorithm for this somewhere? Rectangular surfaces are easy.
>
> Joe Heafner
I don't think there is any "standard" algorithm.
Perhaps you should have written what DID you try...
And, what are your restrictions concerning patches?

There are of course some trivial ways. Map into your sphere through the 
central projection one of the following:
1. A tetrahedron
2. A cube (this is known as the Cobe Sky Cube...)
3. A dodecahedron.
Voilà. May I suggest one more? Thanks...
4. An icosahedron...   (http://space.mit.edu/home/tegmark/icosahedron.gif)

OK, I know, I forgot the octahedron...
Then, the subdivision of the faces you obtain into smaller ones should 
not be too difficult.

Jerzy Karczmarczuk

PS. People who want always have one nice mathematical formula for some 
spherical problems too often forget that it is not necessary to have two 
singularities at the poles, just one is possible with the stereographic 
projection. But the distortions are awful...

**

Re: [Visualpython-users] covering a sphere with patches

[Kadir H. <kha...@ya...>]

You may try something like a Geodesic Dome.

http://en.wikipedia.org/wiki/Geodesic_dome

Kadir



________________________________
 From: Joe Heafner <hea...@gm...>
To: Visualpython-users Visualpython-users <vis...@li...> 
Sent: Tuesday, April 17, 2012 8:12 PM
Subject: [Visualpython-users] covering a sphere with patches
 
Can someone direct me to an algorithm for covering a sphere with patches of equal area for the purposes of illustrating the surface integral in Gauss's law? I've tried three so far and can't get good results. The problem is mostly with the poles and in the foreshortening of the patches near the poles. Is there a standard algorithm for this somewhere? Rectangular surfaces are easy.

Joe Heafner
Sent from one of my Macs


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[Visualpython-users] covering a sphere with patches

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

Can someone direct me to an algorithm for covering a sphere with patches of equal area for the purposes of illustrating the surface integral in Gauss's law? I've tried three so far and can't get good results. The problem is mostly with the poles and in the foreshortening of the patches near the poles. Is there a standard algorithm for this somewhere? Rectangular surfaces are easy.

Joe Heafner
Sent from one of my Macs

[Visualpython-users] Rebuilt VPython 5.73 installer for Mac Python 3.2

[Bruce S. <Bru...@nc...>]

Ralph Martin kindly pointed out that I made a mistake in posting the
new Mac installer for Python 3.2 (it required that Python 3.1 was
installed instead of Python 3.2). Now fixed.

I would appreciate a report from someone using the latest Mac
operating system (Lion), as I built this on Snow Leopard. I don't
expect any problem, because this was also the situation for VPython
5.72, which worked on Lion, but it would be good to know. Thanks.

Bruce Sherwood

Re: [Visualpython-users] bug in vpython path library

[Bruce S. <Bru...@nc...>]

>From what you describe, perhaps a curve object would suit your
purposes better than an extrusion object.

Bruce Sherwood

Re: [Visualpython-users] bug in vpython path library

[Bruce S. <Bru...@nc...>]

I'm afraid this is a feature, not a bug. There just isn't any way that
I can think of for such a sharp turn to work in something called an
"extrusion". Think about creating such an object by extruding metal
and you may see that this is a fundamental problem.

In the example program "extrusion_overview.py", step through the first
page to get an index, then choose page 12 to see an illustration of
the problem.

On the other hand, perhaps you or someone else can come up with some
scheme that would work better.

Bruce Sherwood

On Mon, Apr 16, 2012 at 8:12 PM, sufyan fehe <sis...@ya...> wrote:
> I am using the extrusion object library, path library of Vpyhon for my
> project. my program simply extracts or parses G-codes with X,Y, Z
> coordinates, the program then uses this extracted points as my path, a 2D
> square shape is then extruded through these points or path in that sequence.
> the problem is, these points are line segments, where a line segment is
> define by two points i.e X1,Y1,Z1 and X2,Y2,Z2. Now if the third point
> X3,Y3Z3 is sharp turn, i.e the angle between the line segment becomes > 270,
> the extrusion generates very long spikes or glitches which makes my work
> messy. my G-codes are all accurate, because it is tested. this is a special
> case where the preceding point makes that sharp turn. i showed it to some
> programmers and they say it might be a bug with vpython extrusion library. i
> can share my program with you, or pictures of what i mean. hope i get a
> response from you. thanks
> 1 Attached file| 6KB

Re: [Visualpython-users] bug in vpython path library

[Eric Z. <zar...@gm...>]

Can you share the part of the code in which is made the extrusion?
and if is possible, upload an image and post the link. I had a similar 
problem before, but for don´t talk on the air, is better to see the 
example and try to find the specific solution.
Eric.
El 16/04/2012 22:12, sufyan fehe escribió:
>
>
>
> ------------------------------------------------------------------------
> **
>
> I am using the extrusion object library, path library of Vpyhon for my 
> project. my program simply extracts or parses G-codes with X,Y, Z 
> coordinates, the program then uses this extracted points as my path, a 
> 2D square shape is then extruded through these points or path in that 
> sequence.
> the problem is, these points are line segments, where a line segment 
> is define by two points i.e X1,Y1,Z1 and X2,Y2,Z2. Now if the third 
> point X3,Y3Z3 is sharp turn, i.e the angle between the line segment 
> becomes > 270, the extrusion generates very long spikes or glitches 
> which makes my work messy. my G-codes are all accurate, because it is 
> tested. this is a special case where the preceding point makes that 
> sharp turn. i showed it to some programmers and they say it might be a 
> bug with vpython extrusion library. i can share my program with you, 
> or pictures of what i mean. hope i get a response from you. thanks
> *1*Attached file| *6*KB
>
>
>
>
> ------------------------------------------------------------------------------
> Better than sec? Nothing is better than sec when it comes to
> monitoring Big Data applications. Try Boundary one-second
> resolution app monitoring today. Free.
> http://p.sf.net/sfu/Boundary-dev2dev
>
>
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users

[Visualpython-users] bug in vpython path library

[sufyan f. <sis...@ya...>]

________________________________




 
I am using the extrusion
object library, path library of Vpyhon for my project. my program simply
extracts or parses G-codes with X,Y, Z coordinates, the program then uses this
extracted points as my path, a 2D square shape is then extruded through these points
or path in that sequence.
the problem is, these
points are line segments, where a line segment is define by two points i.e
X1,Y1,Z1 and X2,Y2,Z2. Now if the third point X3,Y3Z3 is sharp turn, i.e the
angle between the line segment becomes > 270, the extrusion generates very
long spikes or glitches which makes my work messy. my G-codes are all accurate,
because it is tested. this is a special case where the preceding point makes
that sharp turn. i showed it to some programmers and they say it might be a bug
with vpython extrusion library. i can share my program with you, or pictures of
what i mean. hope i get a response from you. thanks
1Attached file| 6KB

[Visualpython-users] (no subject)

[sufyan f. <sis...@ya...>]

 
I am using the extrusion
object library, path library of Vpyhon for my project. my program simply
extracts or parses G-codes with X,Y, Z coordinates, the program then uses this
extracted points as my path, a 2D square shape is then extruded through these points
or path in that sequence.
the problem is, these
points are line segments, where a line segment is define by two points i.e
X1,Y1,Z1 and X2,Y2,Z2. Now if the third point X3,Y3Z3 is sharp turn, i.e the
angle between the line segment becomes > 270, the extrusion generates very
long spikes or glitches which makes my work messy. my G-codes are all accurate,
because it is tested. this is a special case where the preceding point makes
that sharp turn. i showed it to some programmers and they say it might be a bug
with vpython extrusion library. i can share my program with you, or pictures of
what i mean. hope i get a response from you. thanks
1Attached file| 6KB

[Visualpython-users] 5.73 tarball for Linux

[Bruce S. <Bru...@nc...>]

On the Linux download page at vpython.org is a new tarball for VPython 5.73.

Bruce Sherwood

[Visualpython-users] Mac VPython 5.73 for 32-bit Python 2.7 and 3.2

[Bruce S. <Bru...@nc...>]

New installers for Mac VPython 5.73 for 32-bit Python 2.7 and 3.2 are
available at vpython.org. There isn't yet a new tarball for VPython
5.73 for Linux.

As many of you know, the Mac version of VPython is built on the Carbon
framework, which is no longer maintained by Apple and will not work
with 64-bit applications. The supported framework is Cocoa, but
efforts by David Scherer and me in 2008 were unsuccessful in using
Cocoa, due to seemingly unsolvable threading problems.

At the moment, both 32-bit and 64-bit versions of Python are available
from python.org, but presumably at some point only 64-bit versions of
Python will be available, at which point the only way to create and
use VPython on a Mac will be to use the X11 window manager, as is done
in the Fink distribution (see below), unless someone figures out how
to base VPython on Cocoa.

One possibility is the following: Suppose that on the Mac it were
obligatory to have a rate or similar statement in an animation loop,
so that instead of depending on having a rendering thread interrupt
the loop 30 times a second or so, you would explicitly state when the
render program could run. This would simplify the threading issues and
might make it possible to base a Mac version of VPython on Cocoa.

Two things encourage me to think that this might be a feasible
solution. One is that I only recently became aware of the fact that on
the Mac animation loops without rate statements run quite erratically.
This suggests that in the vast majority of cases people already put
rate statements in their animation loops. The second is that in
GlowScript (glowscript.org), with syntax similar to VPython but based
on JavaScript instead of Python, rate statements are obligatory due to
the fact that an infinite loop in JavaScript causes the browser to
freeze up. This requirement in GlowScript has not turned out to be
particularly onerous.

Bruce Sherwood

P.S. From the Mac download page at vpython.org:

At http://www.finkproject.org you will find many open source packages
for the Mac, including
http://pdb.finkproject.org/pdb/package.php/visual-py27 which is a Fink
package corresponding to VPython 5.40. Fink packages use the X11
window manager and are Unix-oriented, so the look and feel is
different from native Mac applications.

[Visualpython-users] 5.73 ubuntu 10.04

[Sammel L. <Sam...@gm...>]

Hi somone has managed to get this new version compiled on the Ubuntu LTS 
10.04

this is still the version most of CAD/CAM opensource and also Linuxcnc 
is running on
witch is in python an the best target to use this vpython mpodule in a 
real  therm

Thanks Sammel Lothar From Germany

[Visualpython-users] CVS -> git

[Bruce S. <Bru...@nc...>]

I want to thank Aaron Mavrinac for moving the VPython source files
from the increasingly obsolete CVS-format repository at
sourceforge.net to an up-to-date git repository at github.com. This
news is featured in the "Recent developments" section of vpython.org,
and a message about the change is in the summary of the now-obsolete
CVS repository at sourceforge.net.

Bruce Sherwood

[Visualpython-users] VPython 5.73 for Python 2.7 and 3.2 on Windows

[Bruce S. <Bru...@nc...>]

There is now an installer for VPython 5.73 for Python 2.7 and 3.2,
only for Windows at the moment. This includes minor bug fixes to the
controls module and the text object, but the main issue is having an
installer for Python 3.2.

I plan to maintain installers for Windows and Mac only for Python 2.7
and 3.x. Older installers for Python 2.6 can be found on the
vpython.org download pages.

Bruce Sherwood

Re: [Visualpython-users] Program 22_Gauss_2win.py brings machine to a crawl

[Bruce S. <Bru...@nc...>]

There is a known bug (with an unknown solution) that a VPython program
with while loops but no rate statement locks up on a Mac. I've
inserted rate(50) in all while loops in that program; the program
didn't have any rate statements. You can get a working copy in the
"Lecture-demo materials" section of matterandinteractions.org.

Bruce Sherwood

On Mon, Apr 9, 2012 at 8:27 AM, Joe Heafner <hea...@gm...> wrote:
> This morning in class, my students and I found that M&I demo program 22_Gauss_2win.py brought my MacBook Air and one of our MacBooks to a crawl, barely useable. At the same time, the program executed fine on another students Windows notebook. All of the other demo programs work fine for me but this one hangs after every mouse interaction and I must wait many seconds after each hang to proceed. The two Macs are several generations apart (2006 and 2011). Mine runs Lion and the other runs Leopard. The Windows notebook runs the same Python/VPython installation that I have. Any ideas as to what the problem could be? Nothing stands out to me.
>
> Joe Heafner
> Sent from one of my Macs
>
>
> ------------------------------------------------------------------------------
> For Developers, A Lot Can Happen In A Second.
> Boundary is the first to Know...and Tell You.
> Monitor Your Applications in Ultra-Fine Resolution. Try it FREE!
> http://p.sf.net/sfu/Boundary-d2dvs2
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users

[Visualpython-users] Program 22_Gauss_2win.py brings machine to a crawl

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

This morning in class, my students and I found that M&I demo program 22_Gauss_2win.py brought my MacBook Air and one of our MacBooks to a crawl, barely useable. At the same time, the program executed fine on another students Windows notebook. All of the other demo programs work fine for me but this one hangs after every mouse interaction and I must wait many seconds after each hang to proceed. The two Macs are several generations apart (2006 and 2011). Mine runs Lion and the other runs Leopard. The Windows notebook runs the same Python/VPython installation that I have. Any ideas as to what the problem could be? Nothing stands out to me.

Joe Heafner
Sent from one of my Macs