On Fri, Nov 13, 2009 at 5:09 PM, kstueve <kevin.stu...@gmail.com> wrote:
>
> To sage-dev
> Can someone please explain to me what traits are in the context of
> tvisual? The wiki page for it (http://www.enthought.com/traits from
> the page https://svn.enthought.com/enthought/wiki/TVTKIntroduction) is
> a dead link.
> A google search of either vpython.org or svn.enthought.com produces
> many results for visual, but none for tvisual. I am guessing that
> tvisual is part of TVTK and visual part of VPython.
>
> I see tvtk at the page
> https://svn.enthought.com/enthought/wiki/TVTKIntroduction
> (traited vtk), and vtk at http://mayavi.sourceforge.net/.
> http://www.vtk.org/ says that vtk is the visualization toolkit.
>
> Jason Grout said "Since we also already have momentum for
> incorporating mayavi.." Can someone please give me details. Is Jason
> saying that Sage-dev is in the process of making mayavi part of Sage,
> so it would be easy to use parts of mayavi?
No. To the best of my knowledge nobody is working on including
mayavai + vtk in Sage. VTK is quite difficult to build, to put it
mildly.
> What are the benefits of using tvtk over vpython? Vpython is faster.
> How does Tvtk has a cleaner API?
Note that tvtk and vpython don't work via a web browser. Part of the
challenge of Sage -- and the opportunity -- is making capabilities
available via a webpage. For that, the only options are javascript
(=AJAX) or Java.
> Does anyone have any thoughts on using OpenModelica?
It's license is GPL-incompatible. However, I've been told they are in
the process of changing their license to be GPL-compatible. I hope
this happens.
>
> Another question:
> Time permitting, I would like to be able to solve symbolic physics
> problems. Instead of just giving initial conditions and solving for
> later values, it would be nice to say (symbolically) "it takes t
> seconds for the ball to reach the basket, at what angle was it
> thrown". How might you go about this? I think that this could be
> done using a theorem prover of sorts that searches the space of
> theorems that can be proven from a small set of axioms and givens and
> a set of manipulation rules. Of course this is an NP-complete problem
> that is intractable in general (think Fermat's last theorem),
Fermat's last theorem has nothing to do with NP complete problems, as
far as I know. What connection were you thinking of? I'm curious.
I'm also confused as to what doing physics symbolically has to do with
theorem provers.
> but most
> problems given to freshman physics students are only a few steps long,
> meaning that the tree of possible proofs is relatively small and can
> be exhaustively searched.
> Does Sage have the ability to symbolically simplify "sin^2(theta)+cos^2
> (theta)" to "1"?
Yes:
sage: var('theta')
theta
sage: f = sin(theta)^2 + cos(theta)^2
sage: f.trig_simplify()
1
> For numeric problems such as "at what angle must the ball be thrown to
> reach the basket in 2 seconds?", it might be possible to use some sort
> of binary search to find the correct value.
>
> Here is a link to my (very early) pre-draft of my writeup, so that you
> can view the bibliography.
> http://docs.google.com/View?id=df9q29vh_45dfx2wmfg
>
> I declare Crocker's rules. http://www.sl4.org/crocker.html
And I exercise it :-)
William
>
> Kevin Stueve
>
>
> On Sep 23, 3:31 pm, Fernando Perez <fperez....@gmail.com> wrote:
>> On Wed, Sep 23, 2009 at 4:41 AM, Prabhu Ramachandran
>>
>> <pra...@aero.iitb.ac.in> wrote:
>> > Thanks Fernando. The speed issue is still true but I wouldn't blame
>> > traits since that isn't the source of the bottleneck. I think there are
>> > a little too many events and too many renders. I have not had the time
>> > to profile it carefully.
>>
>> Thanks for the clarifications, Prabhu. I remembered the performance
>> drop, but wasn't sure what all of the reasons were under the hood and
>> I was worried I could misrepresent the issue.
>>
>> It would really be great to have vpython-like performance with the
>> clean tvtk api! Here's to hoping it's possible :)
>>
>> Cheers,
>>
>> f
> >
>
--
William Stein
Associate Professor of Mathematics
University of Washington
http://wstein.org
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