Mehmet Hakan SatmanFibonacci numbers as matrix determinants
Steven G. Johnson@mhsatman With BigInt arithmetic so you can go to larger Fibonacci numbers without overflow:
@stevengj how about the @btime?
@mhsatman This is a terrible way to compute Fibonacci numbers if you care about performance. The fastest method in Julia is about 3000× faster than this for n=499: https://discourse.julialang.org/t/efficient-implementations-of-fibonacci-function-with-interesting-results/18123/5?u=stevengj
Efficient implementations of Fibonacci function with interesting results
The fastest method in Julia is probably to call the optimized C implementation from the underlying libgmp library: function fastfib(n) z = BigInt() ccall((:__gmpz_fib_ui, :libgmp), Cvoid, (Ref{BigInt}, Culong), z, n) return z end This is about 50% faster than your memo-ized fib implementation above (which means your fib function is quite good)!
@stevengj the aim is not to find a fiboanacci number, the aim is to teach how to construct matrices in my side :)