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Manuscript Title: A more efficient version of the WEIGHTS and NJSYM packages. | ||

Authors: N.S. Scott, A. Hibbert | ||

Program title: NJSYM - A MORE EFFICIENT VERSION | ||

Catalogue identifier: AAGD_v3_0Distribution format: gz | ||

Journal reference: Comput. Phys. Commun. 28(1982)189 | ||

Programming language: Fortran. | ||

Computer: CRAY-1. | ||

Operating system: OS 1.10. | ||

RAM: 38K words | ||

Word size: 64 | ||

Keywords: General purpose, Rotation group, Structure, Scattering, Recoupling coefficients, Racah coefficient, 3n-j symbol, Angular momentum, Element matrix, Angular integral. | ||

Classification: 4.1. | ||

Nature of problem:A general recoupling coefficient for an arbitrary number of integer or half integer angular momenta is calculated. | ||

Solution method:The recoupling coefficient is first expressed as a sum over products of Racah coefficients multiplied by (-1) factors and (2j+1)**1/2 factors. This summation is then evaluated using an efficient Rach coefficient subroutine which is a factor of six faster than the original one employed in the NJSYM package. | ||

Restrictions:The program can be used to calculate a recoupling coefficient containing any number of angular momenta by modifying the dimensions of appropriate arrays. | ||

Unusual features:When the program has been used once to evaluate a given recoupling coefficient it is possible to call the routine over and over again for the same coefficient with different angular momenta without re-expressing the recoupling coefficient in terms of Racah coefficients. This facilty now works in all circumstances (see section 2 of the long write-up). | ||

Running time:The test run took 0.5 s execution time on the CRAY-1. |

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