Re: [eigen] Thank you for creating Eigen!

[Alexander Voigt <alexander.voigt@xxxxxxxxxxxxxxxxxxxxx>]

Hi Christoph and Rasmus,

> Christoph Hertzberg wrote:
>
> Eigen::Tensor will not be included into Eigen 3.2, but Eigen 3.3 is
> "very close" to getting released, i.e., you can/should already try
> out Eigen 3.3rc1.

> Rasmus Larsen wrote
>
> That is wonderful to hear! I would just like to point you to the
> Eigen Tensor module, which (at least for Eigen 3.3) supports a
> variety of tensor operations. It actually forms the computational
> basis for Google's opensource TensorFlow project, and we are a few
> people in the TensorFlow team helping to develop/maintain it,
> including the main author Benoit Steiner.

Many thanks for the hints!  I've already tried the alpha version Eigen
3.3 and it looks very promising, in particular the TensorFixedSize
class template.  If it is ok for you, I'll give you some feedback when
we start making use of it.

> Sure! Could you write a short descriptive line about it (similar to the
> other projects)? And to which link of [1] shall we point to?
>
>> [1] https://flexiblesusy.hepforge.org
>>     https://github.com/FlexibleSUSY
>>     arXiv:1406.2319, arXiv:1609.00371

Many thanks for this!  I'd propose the following descriptive line:

  "FlexibleSUSY, a spectrum generator which calculates the masses of
   elementary particles."

It would be great if you could link to
https://flexiblesusy.hepforge.org .

Many thanks and best regards
Alex


On 10/21/2016 06:54 PM, Rasmus Larsen wrote:
> Hi Alexander,
> 
> That is wonderful to hear! I would just like to point you to the Eigen
> Tensor module, which (at least for Eigen 3.3) supports a variety of
> tensor operations. It actually forms the computational basis for
> Google's opensource TensorFlow project, and we are a few people in the
> TensorFlow team helping to develop/maintain it, including the main
> author Benoit Steiner. 
> 
> Take a look at the (not complete) documentation here: 
> https://bitbucket.org/eigen/eigen/src/c313894d14ea4aea129ffe82ad9c1cfec844c0dd/unsupported/Eigen/CXX11/src/Tensor/?at=default
> 
> The main interfaces are defined here:
> https://bitbucket.org/eigen/eigen/src/c313894d14ea4aea129ffe82ad9c1cfec844c0dd/unsupported/Eigen/CXX11/src/Tensor/TensorBase.h?at=default&fileviewer=file-view-default
> 
> The unit tests here provide some usage examples:
> https://bitbucket.org/eigen/eigen/src/c313894d14ea4aea129ffe82ad9c1cfec844c0dd/unsupported/test/?at=default
> 
> On Wed, Oct 19, 2016 at 3:57 AM, Alexander Voigt
> <alexander.voigt@xxxxxxxxxxxxxxxxxxxxx
> <mailto:alexander.voigt@xxxxxxxxxxxxxxxxxxxxx>> wrote:
> 
>     Dear Eigen developers,
> 
>     herewith I'd like to thank you very much creating the incredibly fast
>     and versatile Eigen package!
> 
>     I am a physicist working in theoretical particle physics and I'm using
>     Eigen for one of my projects: FlexibleSUSY [1].  FlexibleSUSY is a
>     spectrum generator, a program that calculates the masses of elementary
>     particles in a very wide class of particle physics models.
> 
>     For calculating the particle masses with high precision, one challenge
>     is to being able to calculate extremely complex matrix expressions
>     very efficiently (the so-called beta-functions [2]).  These matrix
>     expressions are so complicated that they usually span multiple pages
>     and they need to be evaluated tens of thousands of times.  Using
>     Eigen, we are able to evaluate these complicated expressions in an
>     incredibly short time, which gives us a big speed improvement over
>     other spectrum generators (SARAH/SPheno [3], SOFTSUSY [4]) and a high
>     speed is a premiss to study particle physics models at the LHC
>     experiment.  Interestingly, the evaluation of the matrix expressions
>     in C++ using the Eigen library is much faster than the classic matrix
>     multiplication in Fortran (using Fortran's MatMul() function).
> 
>     Best regards,
>     Alexander Voigt
> 
>     P.S.: One Eigen feature which we're looking forward to is rank-3 and
>     -4 tensors, which appear in some extended particle physics models.
>     Thus, we cannot easily handle such models for now due to the missing
>     support of rank-3 and -4 tensors in Eigen 3.2.
> 
>     P.P.S.: If you think FlexibleSUSY is relevant enough, I'd be happy if
>     it could be added to the list of "Projects using Eigen" in the section
>     "Science".
> 
>     [1] https://flexiblesusy.hepforge.org
>     <https://flexiblesusy.hepforge.org>
>         https://github.com/FlexibleSUSY <https://github.com/FlexibleSUSY>
>         arXiv:1406.2319, arXiv:1609.00371
>     [2] arxiv:hep-ph/9311340, arxiv:1107.2670, arxiv:1310.7629
>     [3] http://sarah.hepforge.org/
>     [4] http://softsusy.hepforge.org/

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Dr. Alexander Voigt
Institute for Theoretical Particle Physics and Cosmology
RWTH Aachen
Sommerfeldstr. 14
52074 Aachen
Room: 28A408
Phone: +49 (0)241 80 27049
Fax  : +49 (0)241 80 22187
E-Mail: alexander.voigt@xxxxxxxxxxxxxxxxxxxxx
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