Banking simulation

holmusk.hs

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--                               Banking simulation
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import Control.Monad
import System.Random

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-- Control Paramenters
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yellow = (2, 5, "yellow")
red  = (2, 2, "red")
blue = (5, 1, "blue")

p = 200
alpha = 100

pickP = 0.6
randRange = (0, 1000)
iters = 1000
invIters = 0.001

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betaDist (a,b,_) x  = p * (x^(a-1)) * ((1-x)^(b-1))
pArrival t = 1 - ((exp 1)**((-1.0)*(fromIntegral t) / fromIntegral alpha))

-- intervals = map (uncurry (-)) $ zip a (tail a)
--   where a = map pArrival [1..1000]

waitY :: Integer -> Double
waitY x
  | y > pickP   = z + betaDist yellow (z*invIters)
  | otherwise = z
  where y = pArrival x
        z = fromIntegral x

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statsCol col@(a,b,c) = (maximum aVal - ((sum $ aVal) / (fromIntegral $ length simL)), c)
  where simL = [invIters, invIters*2 .. 1.0]
        aVal = map (\x -> betaDist col x) simL

q3 = snd $ minimum $ map statsCol [yellow, red, blue]

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main = do
-- q1
  xs <- replicateM iters (randomRIO randRange) :: IO [Integer]
  ys <- return $ waitY <$> xs
  putStrLn $ "q1: Average wait: " ++ show ((sum ys)/(fromIntegral $ length xs)) ++ " Maximum wait: "

-- q2

-- q3
  putStrLn $ "q3: closest time: " ++ q3