41 lines
605 B
Lua
41 lines
605 B
Lua
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-- fibonacci function with cache
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-- very inefficient fibonacci function
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function fib(n)
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N=N+1
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if n<2 then
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return n
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else
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return fib(n-1)+fib(n-2)
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end
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end
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-- a general-purpose value cache
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function cache(f)
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local c={}
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return function (x)
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local y=c[x]
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if not y then
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y=f(x)
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c[x]=y
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end
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return y
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end
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end
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-- run and time it
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function test(s,f)
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N=0
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local c=os.clock()
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local v=f(n)
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local t=os.clock()-c
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print(s,n,v,t,N)
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end
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n=arg[1] or 24 -- for other values, do lua fib.lua XX
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n=tonumber(n)
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print("","n","value","time","evals")
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test("plain",fib)
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fib=cache(fib)
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test("cached",fib)
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