Package to calculate and manipulate Fibonacci numbers

The Fibonacci series is constructed using the formula:

F(n) = F(n - 1) + F (n - 2),

By convention: F(0) = 0, and F(1) = 1.

An alternative formula that uses the Golden Ratio can also be used:

F(n) = (PHI^n - phi^n)/sqrt(5) [Lucas' formula],


PHI = (1 + sqrt(5))/2

is the Golden Ratio and

phi = (1 - sqrt(5))/2

is its reciprocal

Requires Math_Integer, and can be used with big integers if the GMP or the BCMATH libraries are present.

This is old code I wrote for PEAR. Originally it was tracked in CVS, then it was moved to SVN, and now I am importing it to git :-)

-- Jesus M. Castagnetto