Ticket #15555 (Murnaghan-Nakayama formula)

[Keren Shao]

It looks like #15555 is still open (and I cannot find any implementation from the documentation.) Can anyone confirm its status with me?

Also, I am trying understand how to contribute, say a script for Murnaghan-Nakayama formula without dependencies, to SageMath but this link http://doc.sagemath.org/html/en/developer/#section-writing-code-for-sage looks like a textbook. Can anyone summarize the high-level process in an algorithmic way?

Thank you.

[Dima Pasechnik]

there are two mostly independent tasks - how to modify/improve Sage code, and how to contribute these changes to Sage.

which of the two would you like to be explained?

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[Eric Gourgoulhon]

Le samedi 2 novembre 2019 13:56:47 UTC+1, Keren Shao a écrit :

It looks like #15555 is still open (and I cannot find any implementation from the documentation.) Can anyone confirm its status with me?

Also, I am trying understand how to contribute, say a script for Murnaghan-Nakayama formula without dependencies, to SageMath but this link http://doc.sagemath.org/html/en/developer/#section-writing-code-for-sage looks like a textbook. Can anyone summarize the high-level process in an algorithmic way?

I don't know if this is what you are looking for, but here is some short text for new contributors, which summarizes some parts of the developer guide: 

https://sagemanifolds.obspm.fr/contrib.html

This is tailored to the manifold part of SageMath, but I guess you can easily adapt to your needs.

Best wishes,

Eric.

[Keren Shao]

Could you please explain both (just high level steps, assuming my module are standalone python scripts that imports nothing other than sage/standard library)?

On Saturday, November 2, 2019 at 6:04:16 AM UTC-7, Dima Pasechnik wrote:

there are two mostly independent tasks - how to modify/improve Sage code, and how to contribute these changes to Sage.

which of the two would you like to be explained?

On Sat, 2 Nov 2019, 14:56 Keren Shao, <k5s...@ucsd.edu> wrote:

It looks like #15555 is still open (and I cannot find any implementation from the documentation.) Can anyone confirm its status with me?

Also, I am trying understand how to contribute, say a script for Murnaghan-Nakayama formula without dependencies, to SageMath but this link http://doc.sagemath.org/html/en/developer/#section-writing-code-for-sage looks like a textbook. Can anyone summarize the high-level process in an algorithmic way?

Thank you.

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[Dima Pasechnik]

On Sat, 2 Nov 2019, 18:06 Keren Shao, <k5s...@ucsd.edu> wrote:
>
> Could you please explain both (just high level steps, assuming my module are standalone python scripts that imports nothing other than sage/standard library)?

Stand-alone Python scripts doing a particular maths computation don't
really belong to Sagemath library.

A natural addition to Sage would be a method to compute the value of
an irred. character on a group element (or just the corr. partition).

Characters of the symmetric group come in different ways into Sage,
from the symmetric group (a), from the
symmetric functions (b), and directly from partitions (c)

(a) Have you seen
https://ask.sagemath.org/question/33776/evaluation-of-character-of-symmetric-group/
?
(which points at
https://doc.sagemath.org/html/en/reference/combinat/sage/combinat/symmetric_group_representations.html#sage.combinat.symmetric_group_representations.SymmetricGroupRepresentation
which documents code in sage/combinat/symmetric_group_representations.py)

(b) http://doc.sagemath.org/html/en/reference/combinat/sage/combinat/sf/character.html

(c) http://doc.sagemath.org/html/en/reference/combinat/sage/combinat/partition.html?highlight=partition#sage.combinat.partition.Partition

For (a), computing the character values (that's what
Murnaghan-Nakayama formula does)
is available, although I don't know how efficient it is.

For (b), I don't even know how to get character values (would be good
to find out and document...)

For (c), one can think of adding Murnaghan-Nakayama as a method for
a partition
(which would take another partition and compute the corr. character value)
After all, there is already character_polynomial() there, so this does
not look unnatural place to add things
related to characters.

Probably (c) looks like the easiest place to add Murnaghan-Nakayama.

So this addresses "how to modify/improve Sage code".
Once you modified python/cython sage code, you need to update/rebuild,
by running

./sage -b

(this suffices for Python code in 100% cases, for Cython sometimes
more is needed...)

------------------

Once you have such a modifiction ready, you need to create a git
branch on Sage's git repo, and put it up for review
on trac.sagemath.org (this is documented already quite well, I think).

HTH
Dima

>
> On Saturday, November 2, 2019 at 6:04:16 AM UTC-7, Dima Pasechnik wrote:
>>
>> there are two mostly independent tasks - how to modify/improve Sage code, and how to contribute these changes to Sage.
>>
>> which of the two would you like to be explained?
>>
>> On Sat, 2 Nov 2019, 14:56 Keren Shao, <k5s...@ucsd.edu> wrote:
>>>
>>> It looks like #15555 is still open (and I cannot find any implementation from the documentation.) Can anyone confirm its status with me?
>>>
>>> Also, I am trying understand how to contribute, say a script for Murnaghan-Nakayama formula without dependencies, to SageMath but this link http://doc.sagemath.org/html/en/developer/#section-writing-code-for-sage looks like a textbook. Can anyone summarize the high-level process in an algorithmic way?
>>>
>>> Thank you.
>>>
>>> --
>>> You received this message because you are subscribed to the Google Groups "sage-devel" group.
>>> To unsubscribe from this group and stop receiving emails from it, send an email to sage-...@googlegroups.com.
>>> To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/3067c2fe-1588-40f9-aeba-74e5f9c8dc7e%40googlegroups.com.
>
> --
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