Opened 5 years ago

Closed 2 years ago

#14107 closed enhancement (fixed)

Expose quantum Littlewood-Richardson coefficients from lrcalc

Reported by: nthiery Owned by: sage-combinat
Priority: major Milestone: sage-6.9
Component: combinatorics Keywords: days45, lrcalc
Cc: tscrim Merged in:
Authors: Frédéric Chapoton, Travis Scrimshaw Reviewers: Frédéric Chapoton
Report Upstream: N/A Work issues:
Branch: 4637407 (Commits) Commit: 46374079d04c4cdfb7dc72f6dd12691d396ec9da
Dependencies: Stopgaps:

Description

Beside Littlewood-Richardson coefficient calculations and fusion products, Anders Buch's lrcalc C library implements quantum products, using the rim-hook rewriting rule (this corresponds to cup products in the cohomology of quantum Grassmanian variety). The latter functionality needs to be exposed in Sage's interface to lrcalc.

Roadmap:

Change mult to accept a "quantum" argument:

def mult(part1, part2, maxrows=None, level=None, quantum=None):
    """

    ...

    - ``quantum`` -- an element of a ring


    ...

    EXAMPLES::

        sage: var('q')
        sage: mult([1],[2,1],2,2, quantum=q)
        {[2, 2]: 1, []: q}
        sage: mult([2,1],[2,1],2,2, quantum=q)
        {[2]: q, [1,1]: q} 
   """

If quantum is set, then maxrows and level should be set. Looking at <lrcalc>src/mult.c one would just need to call the quantum_reduce function function on the result of lrcalc's mult_c. The result is a list of hash tables, each giving one homogeneous pieces of the result w.r.t. q.

Attachments (1)

trac_14107_quantum_coho.patch (3.8 KB) - added by chapoton 4 years ago.

Download all attachments as: .zip

Change History (14)

comment:1 Changed 4 years ago by jdemeyer

  • Milestone changed from sage-5.11 to sage-5.12

Changed 4 years ago by chapoton

comment:2 Changed 4 years ago by chapoton

Here is a patch which is not working !

I have been unable to sort things out.

Maybe some Cython expert can help to correct it ?

comment:3 Changed 4 years ago by tscrim

  • Cc tscrim added

comment:4 Changed 4 years ago by vbraun_spam

  • Milestone changed from sage-6.1 to sage-6.2

comment:5 Changed 3 years ago by vbraun_spam

  • Milestone changed from sage-6.2 to sage-6.3

comment:6 Changed 3 years ago by vbraun_spam

  • Milestone changed from sage-6.3 to sage-6.4

comment:7 Changed 3 years ago by chapoton

  • Branch set to u/chapoton/14107
  • Commit set to d0e9d3588672cdd3b080ab352824ea89027ab1b1

New commits:

48ec624trac_14107_quantum_coho.patch
d0e9d35trac #14107 branch not working

comment:8 Changed 2 years ago by tscrim

  • Authors set to Frédéric Chapoton, Travis Scrimshaw
  • Branch changed from u/chapoton/14107 to u/tscrim/quantum_LR_coeff-14107
  • Commit changed from d0e9d3588672cdd3b080ab352824ea89027ab1b1 to 37e2e9d18eb73df0f631366117b95cbfb79cd1c2
  • Milestone changed from sage-6.4 to sage-6.9
  • Status changed from new to needs_review

New commits:

2b012bbMerge branch 'u/chapoton/14107' of trac.sagemath.org:sage into u/tscrim/quantum_LR_coeff-14107
37e2e9dImplementing the quantum product from lrcalc.

comment:9 Changed 2 years ago by git

  • Commit changed from 37e2e9d18eb73df0f631366117b95cbfb79cd1c2 to 46374079d04c4cdfb7dc72f6dd12691d396ec9da

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

4637407Implementing the quantum product from lrcalc and some cython cleanup.

comment:10 Changed 2 years ago by tscrim

I also added some more explicit cdef/type info, which should result in faster code.

comment:11 Changed 2 years ago by chapoton

  • Reviewers set to Frédéric Chapoton
  • Status changed from needs_review to positive_review

Thanks a lot Travis.

ok, good to go. Next step would be to wrap that into an algebra.

comment:12 Changed 2 years ago by tscrim

Thanks for doing the review. I could finally do this ticket now that I've learned more Cython. I agree that is definitely the next step. Will you be creating said wrapper?

(Sorry, I have to do a Matrix pun: I know CyFu. :P)

comment:13 Changed 2 years ago by vbraun

  • Branch changed from u/tscrim/quantum_LR_coeff-14107 to 46374079d04c4cdfb7dc72f6dd12691d396ec9da
  • Resolution set to fixed
  • Status changed from positive_review to closed
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