#10333: An interface to Anders Buch's Littlewood-Richardson Calculator
``lrcalc``
----------------------------------------------+-----------------------------
Reporter: mhansen | Owner: sage-combinat
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-5.0
Component: optional packages | Keywords: spkg package,
Schubert calculus, Littlewood-Richardson, days30
Work_issues: | Upstream: N/A
Reviewer: Nicolas Thiery, Anne Schilling | Author: Mike Hansen,
Anders Buch, Nicolas Thiery, Anne Schilling
Merged: | Dependencies:
----------------------------------------------+-----------------------------
Old description:
> The attached patch, and spkg implements an interface to Anders Buch's
> Littlewood-Richardson Calculator ``lrcalc``
>
> The "Littlewood-Richardson Calculator" is a C library for fast
> computation of Littlewood-Richardson (LR) coefficients and products of
> Schubert polynomials. It handles single LR coefficients, products of
> and coproducts of Schur functions, skew Schur functions, and
> fusion products. All of the above are achieved by counting LR
> (skew)-tableaux (also called Yamanouchi (skew)-tableaux) of
> appropriate shape and content by iterating through them.
> Additionally, ``lrcalc`` handles products of Schubert polynomials.
>
> The web page of ``lrcalc`` is: http://math.rutgers.edu/~asbuch/lrcalc/
>
> Here is a short extract of the doc:
>
> {{{
> EXAMPLES::
>
> sage: import sage.libs.lrcalc.lrcalc as lrcalc
>
> Compute a single Littlewood-Richardson coefficient::
>
> sage: lrcalc.lrcoef([3,2,1],[2,1],[2,1]) #optional -
> lrcalc
> 2
>
> Compute a product of Schur functions; return the coefficients in the
> Schur expansion::
>
> sage: lrcalc.mult([2,1], [2,1]) #optional -
> lrcalc
> {[3, 3]: 1, [4, 2]: 1, [3, 1, 1, 1]: 1, [4, 1, 1]: 1, [2, 2, 2]: 1,
> [3, 2, 1]: 2, [2, 2, 1, 1]: 1}
> }}}
>
> Add optional package [attachment:lrcalc-1.1.6beta.spkg]
>
> Apply: [attachment:trac_10333-lrcalc-final.patch]
>
> Making lrcalc into a standard package in the next Sage release is the
> topic of the followup ticket: #12284
New description:
The attached patch, and spkg implements an interface to Anders Buch's
Littlewood-Richardson Calculator ``lrcalc``
The "Littlewood-Richardson Calculator" is a C library for fast
computation of Littlewood-Richardson (LR) coefficients and products of
Schubert polynomials. It handles single LR coefficients, products of
and coproducts of Schur functions, skew Schur functions, and
fusion products. All of the above are achieved by counting LR
(skew)-tableaux (also called Yamanouchi (skew)-tableaux) of
appropriate shape and content by iterating through them.
Additionally, ``lrcalc`` handles products of Schubert polynomials.
The web page of ``lrcalc`` is: http://math.rutgers.edu/~asbuch/lrcalc/
Here is a short extract of the doc:
{{{
EXAMPLES::
sage: import sage.libs.lrcalc.lrcalc as lrcalc
Compute a single Littlewood-Richardson coefficient::
sage: lrcalc.lrcoef([3,2,1],[2,1],[2,1]) #optional -
lrcalc
2
Compute a product of Schur functions; return the coefficients in the Schur
expansion::
sage: lrcalc.mult([2,1], [2,1]) #optional -
lrcalc
{[3, 3]: 1, [4, 2]: 1, [3, 1, 1, 1]: 1, [4, 1, 1]: 1, [2, 2, 2]: 1,
[3, 2, 1]: 2, [2, 2, 1, 1]: 1}
}}}
Add optional package [attachment:lrcalc-1.1.6beta.spkg]
Apply: [attachment:trac_10333-lrcalc-final.patch]
Making lrcalc into a standard package in the next Sage release is the
topic of the followup ticket: #11563
--
Comment(by nthiery):
Replying to [comment:27 jdemeyer]:
> Maybe this should be discussed on sage-devel? I don't have an opinion
either way.
Ok, I just relaunched the discussion there:
http://groups.google.com/group/sage-devel/msg/9a7b4987ae974b2b
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10333#comment:28>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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