This follows from the recent micro-benchmarking discussion, though as
it concerns a potential bug, I'm starting a new thread.
With this (very inefficient) implementation of fib,
(defn fib [n]
(if (<= n 1)
1
(+ (fib (dec n)) (fib (- n 2)))))
computing (fib 40) takes, give or take, 12 seconds on a Core 2 (2
GHz).
Substituting unchecked-{add,dec,subtract} for +, dec and -, I've not
been able to complete (fib 40). For (fib 20), the original takes 63 ms
whereas the unchecked version takes 2215 ms.
Que pasa?
--
Michel
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