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 O(j9) or more operations and O(j2) or more space, where j is the average spin. We present an algorithm that computes the 10j symbol using O(j5) operations and O(j2) space, and a variant that uses O(j6) operations and a constant amount of space. An implementation has been made available on the web.
Classical and Quantum Gravity
- Pub Date:
- March 2002
- General Relativity and Quantum Cosmology
- 9 pages, 5 postscript figures. This is the version that is to appear in Classical and Quantum Gravity. See also http://jdc.math.uwo.ca/spin-foams