[SciPy-Dev] GSoC'18 participation?

Sat Jan 20 05:09:15 EST 2018

Thanks for the suggestion, Benoit! I think the easiest way to achieve that is sample a quaternion uniformly on a unit 4D sphere. 

By the way I updated the ideas wiki and I will include your suggestion as well. Also as was suggested we could use a more general name scipy.spatial.transform.

Nikolay

Hi,

 I have used that library quite a few times, and it is rather slow. Adding a transformation (or, for starters, rotation) module to scipy would be, in my opinion, a nice addition. 

 Speaking about adding a few algorithms, one interesting add could be a function to uniformly sample the rotation space. It is a core functionality needed in a number of cases, and not that straightforward to perform properly (again, depending on the chosen formalism for representing the rotation). 

 Best

 Benoit

On 19/01/2018 22:28, oss wrote:

Hello, 

Maybe this could come in handy regarding transforms matrices quaternions

 etc.

https://www.lfd.uci.edu/~gohlke/code/transformations.py.html

Best

Tryfon

On Jan 19, 2018, at 4:25 PM, Eric Larson <larson.eric.d at gmail.com> wrote:

I have personally run into the need for such transformations in two separate domains (3D visualization, neuroscience / electrophysiology) and I know it's used in multiple other places, too. So I think it would be sufficiently general. I'd look forward to having it in SciPy! 

I'd be happy to be a secondary mentor on this if you (or someone else) wants to be primary.

Best, 

Eric

On Fri, Jan 19, 2018 at 10:11 AM, Nikolay Mayorov <nikolay.mayorov at zoho.com> wrote:

Hi!

 I have this idea, which I'm well familiar with. The module would be called like scipy.spatial.rotation and be devoted to the rotation formalism in 3 dimensions. 

 The main objects are Euler angles (and their variations), direction cosine matrices, quaternions and rotation vectors. We can go with an abstraction class Rotation (using DCMs or Qs internally), but we should be able to create that from any representation and see it in any representation. In spirit of scipy/numpy we use vectorized/bulk approaches (i.e. many rotations in single Rotation class).

 Rotation should support 2 operations: compose 2 consecutive rotations and rotate/project a 3d vector.  Of course all procedures must be 100% robust and there are some fine points, especially in conversions between representations.Also we can add some algorithms, like: quaternion interpolation (SLERP), least-squares vector matching by a rotation (Whabba's problem), more advanced and less known algotithms for rotation interpolation, and I will try to come up with something more. 

Overall it seems reasonably straightforward , but with enough challenges in design and implementation

As currently described, it might be not enough volume for the GSoC, but we can develop it farther. 

Also I'm not sure if its applicability is broad enough to include it into scipy. I believe similar functionality is available in Aerospace toolbox in Matlab. I want to hear some opinions on that.

Nikolay

---- On Wed, 10 Jan 2018 17:02:33 +0500 jomsdev at gmail.com  wrote ----

Hi all,

Last year I started implementing some methods for Randomized Numerical Linear Algebra (RNLA) in scipy.

By now it is only the CountMin Sketch (clarkson_woodruff_transformation) for reducing the dimensionality of a vector space to an embedded space.

I think that it would be interesting to add to scipy other methods for subspace embedding (like the Johnson-Lindenstrauss) and build some algorithms on top of it for things like least squeres or low rank approximation.

Would some other people be interesting in this?

PS: I have a project called RandNLA where I implemented some of the methods of RNLA. The idea is to implement only the most important methods of RNLA in scipy and have this other library for experimenting with new methods and APIs. That will let us not overloading scipy with features if people are not interested in them and focus on the ones that really brings value to the community.

Thanks,

Jordi.

On 10 January 2018 at 10:42, Ralf Gommers <ralf.gommers at gmail.com> wrote:

Hi all,

The GSoC schedule is a bit earlier than normal this year. The PSF is asking for ideas pages to be up and in decent shape by Jan 19th. So we'll need to come up with some content quick if we want to participate.

Who is interested in mentoring this year?

I'm happy to do the admin again, but probably won't have time to mentor.

Cheers,

Ralf

_______________________________________________

 SciPy-Dev mailing list

 SciPy-Dev at python.org

 https://mail.python.org/mailman/listinfo/scipy-dev

_______________________________________________

 SciPy-Dev mailing list 

 SciPy-Dev at python.org 

 https://mail.python.org/mailman/listinfo/scipy-dev 

_______________________________________________

 SciPy-Dev mailing list

 SciPy-Dev at python.org

 https://mail.python.org/mailman/listinfo/scipy-dev

_______________________________________________

 SciPy-Dev mailing list

 SciPy-Dev at python.org

 https://mail.python.org/mailman/listinfo/scipy-dev

_______________________________________________ SciPy-Dev mailing list SciPy-Dev at python.org https://mail.python.org/mailman/listinfo/scipy-dev 

_______________________________________________

SciPy-Dev mailing list 

SciPy-Dev at python.org 

https://mail.python.org/mailman/listinfo/scipy-dev 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/scipy-dev/attachments/20180120/d9bf3d39/attachment.html>