CGC — Clebsch-Gordan Coefficients

CGC is a small C library and test program for calculating high order Clebsch-Gordan coupling coefficients. Here, high order means principal quantum numbers of up to about 260 in ordinary double precision and 400 or more in long double precision. When using the GMP arbitrary precision math library, there is essentially no limit on the maximum quantum numbers. The code was written by Dave Ritchie.

CGC was developed on a 64-bit Linux system, but it should be possible to compile it on Mac OS X or Windows. The only external pre-requisite is the GMP multiple precision math library.

CGC is released under the Gnu LGPL licence. This means you can include it in your own code.

CGC 1.0.0

A brief README file is included in the software installation.

The following publication describes the CGC algorithm:

• Whole Number Recursion Formulae for High Order Clebsch-Gordan Coupling Coefficients. D.W. Ritchie, 2018. To appear.