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@quephird quephird/Pi.hs
Created Jan 21, 2016

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What would you like to do?
Just an exercise to compute pi based on random number generation
module Pi where
import Data.List.Split (chunksOf)
import System.Random (newStdGen, randoms)
randomTuples :: Int -> IO [(Float, Float)]
randomTuples n = do
seed1 <- newStdGen
seed2 <- newStdGen
let xs = randoms seed1 :: [Float]
ys = randoms seed2 :: [Float]
return $ take n $ zipWith (,) xs ys
isInUnitCircle :: (Float, Float) -> Bool
isInUnitCircle (x,y) =
(x-0.5)**2 + (y-0.5)**2 < 0.25
main = do
putStrLn "How many random tuples do you want to use to approximate π?"
count <- getLine
allTuples <- randomTuples $ read count
let insideTuples = filter isInUnitCircle allTuples
pi = 4.0 * (fromIntegral $ length insideTuples) / (fromIntegral $ length allTuples)
putStrLn $ show pi
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