commit 1d4a17fa529d674476b4b84fd3195afc7ce0e966 parent 2e321fc7c01f52f4325bf7bffd450cf0c07f0621 Author: Jared Tobin <jared@jtobin.ca> Date: Sat, 7 Jul 2018 13:25:37 +1200 Simplify. Diffstat:
| M | 20180705_estimate_pi/Pi.hs | | | 16 | ++++++---------- |
1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/20180705_estimate_pi/Pi.hs b/20180705_estimate_pi/Pi.hs @@ -1,5 +1,4 @@ {-# OPTIONS_GHC -Wall -fno-warn-type-defaults #-} -{-# LANGUAGE ScopedTypeVariables #-} import Control.Monad.Primitive (PrimMonad, PrimState) import System.Random.MWC as MWC @@ -8,22 +7,19 @@ import Pipes ((>->)) import qualified Pipes as P import qualified Pipes.Prelude as P -sample :: forall m. PrimMonad m => Gen (PrimState m) -> P.Producer Bool m () +sample + :: PrimMonad m + => Gen (PrimState m) -> P.Producer Bool m () sample prng = do - val <- P.lift (relPrime prng) + val <- P.lift (rprime <$> uniform prng <*> uniform prng) P.yield val sample prng where - relPrime rng = - rprime <$> (uniform rng :: m Word) <*> (uniform rng :: m Word) - + rprime :: Word -> Word -> Bool rprime a b = gcd a b == 1 count :: Num a => L.Fold Bool a -count = L.Fold alg 0 id where - alg acc tru - | tru = acc + 1 - | otherwise = acc +count = L.Fold (\acc tr -> if tr then acc + 1 else acc) 0 id avg :: Fractional a => L.Fold Bool a avg = (/) <$> count <*> L.genericLength