An interface to Anders Buch's Littlewood-Richardson Calculator lrcalc #10333
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
CC: @sagetrac-sage-combinat @asbuch @saliola
Component: packages: optional
Keywords: spkg package, Schubert calculus, Littlewood-Richardson, days30
Author: Mike Hansen, Anders Buch, Nicolas M. Thiéry, Anne Schilling
Reviewer: Nicolas M. Thiéry, Anne Schilling
Merged: sage-5.0.beta2
Issue created by migration from https://trac.sagemath.org/ticket/10333