#10333: An interface to Anders Buch's Littlewood-Richardson Calculator
``lrcalc``
----------------------------------------------+-----------------------------
Reporter: mhansen | Owner: sage-combinat
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-4.7.1
Component: combinatorics | 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:
> 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}
> }}}
>
> Apply: trac_10333-lrcalc-final.patch
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 lrcalc-1.1.5b.spkg
Apply: trac_10333-lrcalc-final.patch
--
Comment(by nthiery):
According to the vote on http://groups.google.com/group/sage-
devel/browse_thread/thread/2e7114375f6f88a5/, there is a consensus on
making lrcalc a standard package, after a one release probation period in
order to follow the official rule. See: #11563
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10333#comment:13>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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