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Hi,<br>
<br>
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. <br>
<br>
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). <br>
<br>
Best<br>
Benoit<br>
<br>
<br>
<div class="moz-cite-prefix">On 19/01/2018 22:28, oss wrote:<br>
</div>
<blockquote type="cite"
cite="mid:C0FFA963-9481-4E38-AC59-C74369D3A7DA@multiwave.ch">
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
Hello,
<div class=""><br class="">
</div>
<div class="">Maybe this could come in handy regarding transforms
matrices quaternions</div>
<div class=""> etc.</div>
<div class=""><br class="">
</div>
<div class=""><a
href="https://www.lfd.uci.edu/%7Egohlke/code/transformations.py.html"
class="" moz-do-not-send="true">https://www.lfd.uci.edu/~gohlke/code/transformations.py.html</a></div>
<div class=""><br class="">
</div>
<div class="">Best</div>
<div class=""><br class="">
</div>
<div class="">Tryfon</div>
<div class=""><br class="">
<div><br class="">
<blockquote type="cite" class="">
<div class="">On Jan 19, 2018, at 4:25 PM, Eric Larson <<a
href="mailto:larson.eric.d@gmail.com" class=""
moz-do-not-send="true">larson.eric.d@gmail.com</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<div dir="ltr" class="">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!
<div class=""><br class="">
</div>
<div class="">I'd be happy to be a secondary mentor on
this if you (or someone else) wants to be primary.</div>
<div class=""><br class="">
</div>
<div class="">Best,
<div class="">Eric</div>
<div class=""><br class="">
</div>
</div>
</div>
<div class="gmail_extra"><br class="">
<div class="gmail_quote">On Fri, Jan 19, 2018 at 10:11
AM, Nikolay Mayorov <span dir="ltr" class=""><<a
href="mailto:nikolay.mayorov@zoho.com"
target="_blank" class="" moz-do-not-send="true">nikolay.mayorov@zoho.com</a>></span>
wrote:<br class="">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class="">
<div
style="font-size:10pt;font-family:Verdana,Arial,Helvetica,sans-serif"
class="">
<div id="m_1873504344155388281message" class="">
<div class="">Hi!<br class="">
<br class="">
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. <br
class="">
<br class="">
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).<br class="">
<br 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.
<div class=""><br class="">
</div>
<div class="">Overall it seems reasonably
straightforward , but with enough
challenges in design and implementation<br
class="">
</div>
<div class=""><br class="">
</div>
<div class="">As currently described, it
might be not enough volume for the GSoC,
but we can develop it farther. </div>
<div class=""><br class="">
</div>
<div class="">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.<br class="">
<div class=""><br class="">
</div>
<div class="">Nikolay</div>
<div class=""><br class="">
</div>
<div class="">
<div id="m_1873504344155388281content"
class=""><br class="">
---- On Wed, 10 Jan 2018 17:02:33
+0500 <b class=""> <a
href="mailto:jomsdev@gmail.com"
target="_blank" class=""
moz-do-not-send="true">jomsdev@gmail.com</a>
</b> wrote ----<span class=""><br
class="">
<br class="">
<blockquote style="border-left:1px
solid
rgb(204,204,204);padding-left:6px;margin-left:5px"
class="">
<div class="">
<div dir="ltr" class="">
<div class="">
<div class="">
<div class="">
<div class="">Hi all,<br
class="">
<br class="">
</div>
Last year I started
implementing some
methods for Randomized
Numerical Linear Algebra
(RNLA) in scipy. <br
class="">
</div>
By now it is only the
CountMin Sketch
(clarkson_woodruff_<wbr
class="">transformation)
for reducing the
dimensionality of a vector
space to an embedded
space. <br class="">
</div>
</div>
<div class=""><br class="">
</div>
<div class="">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.</div>
<div class=""><br class="">
</div>
<div class="">Would some other
people be interesting in
this?<br class="">
</div>
<div class=""><br class="">
</div>
<div class=""><br class="">
</div>
<div class="">PS: I have a
project called <a
href="https://github.com/jomsdev/randNLA"
target="_blank" class=""
moz-do-not-send="true">RandNLA</a>
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.</div>
<div class=""><br class="">
</div>
<div class="">Thanks,</div>
<div class=""><br class="">
</div>
<div class="">Jordi.<br
class="">
</div>
</div>
<div class=""><br class="">
<div class="">On 10 January
2018 at 10:42, Ralf Gommers
<span class=""><<a
href="mailto:ralf.gommers@gmail.com"
target="_blank" class=""
moz-do-not-send="true">ralf.gommers@gmail.com</a>></span>
wrote:<br class="">
<blockquote style="margin:0
0 0 0.8ex;border-left:1px
rgb(204,204,204)
solid;padding-left:1ex"
class="">
<div dir="ltr" class="">
<div class="">
<div class="">
<div class="">
<div class="">
<div class="">Hi
all,<br
class="">
<br class="">
</div>
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.<br
class="">
<br class="">
</div>
Who is interested
in mentoring this
year?<br class="">
<br class="">
</div>
I'm happy to do the
admin again, but
probably won't have
time to mentor.<br
class="">
<br class="">
</div>
Cheers,<br class="">
</div>
Ralf<br class="">
<br class="">
</div>
<br class="">
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