criterion-1.6.4.1: examples/Fibber.hs

{- cabal:
build-depends: base, criterion
-}

import Criterion.Main

-- The function we're benchmarking.
fib :: Int -> Int
fib m | m < 0     = error "negative!"
      | otherwise = go m
  where
    go 0 = 0
    go 1 = 1
    go n = go (n-1) + go (n-2)

main :: IO ()
main = defaultMain [
  bgroup "fib" [ bench "1"  $ whnf fib 1
               , bench "5"  $ whnf fib 5
               , bench "9"  $ whnf fib 9
               , bench "11" $ whnf fib 11
               ]
  ]