Subversion Repositories WoWGM

-- fibonacci function with cache

-- very inefficient fibonacci function

function fib(n)

	N=N+1

	if n<2 then

		return n

	else

		return fib(n-1)+fib(n-2)

	end

end

-- a general-purpose value cache

function cache(f)

	local c={}

	return function (x)

		local y=c[x]

		if not y then

			y=f(x)

			c[x]=y

		end

		return y

	end

end

-- run and time it

function test(s,f)

	N=0

	local c=os.clock()

	local v=f(n)

	local t=os.clock()-c

	print(s,n,v,t,N)

end

n=arg[1] or 24		-- for other values, do lua fib.lua XX

n=tonumber(n)

print("","n","value","time","evals")

test("plain",fib)

fib=cache(fib)

test("cached",fib)