There is a nice matrix representation of consecutive Fibonacci numbers: [[1, 1], [1, 0]] ** n = [[F_n+1, F_n], [F_n, F_n-1]]. Using the third party mpmath module, which uses arbitrary precision floating point arithmetic, we can calculate the n'th Fibonacci number for an arbitrary n as follows:
import mpmath A = mpmath.matrix([[1, 1], [1, 0]]) F = A ** n The n'th Fibonacci number is then found as the elements [0, 1] and [1, 0] in the matrix F. This is more expensive than the formula involving the golden ratio, but I like the compact representation. -- http://mail.python.org/mailman/listinfo/python-list
