# GYutsis: heuristic based calculation of general recoupling coefficients

## Description

Abstract General angular momentum recoupling coefficients can be expressed as a summation formula over products of 6-j coefficients. Yutsis, Levinson and Vanagas developed graphical techniques for representing the general recoupling coefficient as a cubic graph and they describe a set of reduction rules allowing a stepwise generation of the corresponding summation formula. This paper is a follow up to [Van Dyck and Fack, Comput. Phys. Comm. 151 (2003) 353–368] where we described a heuristic algorithm ... Title of program: GYutsis: VAN DYCK, FACK Catalogue Id: ADRM_v2_0 [ADSA] Nature of problem A general recoupling coefficient for an arbitrary number of (integer or half-integer) angular momenta can be expressed as a formula consisting of products of 6-j coefficients summed over a certain number of variables . Such a formula can be generated using the program GYutsis (with a grap hical user front end ) or CycleCostAlgorithm (with a text-mode user fron t end). Versions of this program held in the CPC repository in Mendeley Data ADRM_v1_0; CycleCostAlgorithm, GYutsis; 10.1016/S0010-4655(02)00733-6 ADRM_v2_0; GYutsis: VAN DYCK, FACK; 10.1016/S0010-4655(03)00280-7 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2019)