  The 10j symbol is a spin network that appears in the partition function for
the Barrett-Crane model of Riemannian quantum gravity. Elementary methods of
calculating the 10j symbol require order(j^9) or more operations and order(j^2)
or more space, where j is the average spin. We present an algorithm that
computes the 10j symbol using order(j^5) operations and order(j^2) space, and a
variant that uses order(j^6) operations and a constant amount of space. An
implementation has been made available on the web.

General Relativity and Quantum Cosmology