Created
January 21, 2016 00:11
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Just an exercise to compute pi based on random number generation
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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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