{-# LANGUAGE RankNTypes #-}
module Main where
import Control.Monad
import Data.AEq
import Data.Monoid
import Data.Summary.Double( Summary )
import qualified Data.Summary.Double as S
import Test.QuickCheck
import Test.Framework
import Test.Framework.Providers.QuickCheck2
import Control.Monad.MC.Walker
prop_table_probs :: Weights -> Bool
prop_table_probs (Weights n ws) =
let table = computeTable n ws
in all (\i -> probOf table i ~== ps !! i) [0..n-1]
where
ps = probsFromWeights ws
prop_table_index :: Weights -> Unif -> Bool
prop_table_index (Weights n ws) (Unif u) =
let table = computeTable n ws
i = indexTable table u
in i >= 0 && i < n && (ws !! i > 0)
tests_Walker :: Test
tests_Walker = testGroup "Walker"
[ testProperty "table probabilities" prop_table_probs
, testProperty "table indexing" prop_table_index
]
probOf :: Table -> Int -> Double
probOf table i =
(((sum . map ((1-) . fst) . filter ((==i) . snd))
(map (component table) [0..n-1]))
+ (fst . component table) i) / fromIntegral n
where
n = tableSize table
prop_monoid_update_equiv :: [Double] -> [Double] -> Bool
prop_monoid_update_equiv xs ys =
approxEqualS (S.fromList $ xs <> ys)
(S.fromList xs <> S.fromList ys)
prop_monoid_assoc :: [Double] -> [Double] -> [Double] -> Bool
prop_monoid_assoc xs ys zs =
let (sxs, sys, szs) = (S.fromList xs, S.fromList ys, S.fromList zs)
in ((sxs <> sys) <> szs) `approxEqualS` (sxs <> (sys <> szs))
prop_monoid_commute :: [Double] -> [Double] -> Bool
prop_monoid_commute xs ys =
let (sxs, sys) = (S.fromList xs, S.fromList ys)
in (sxs <> sys) `approxEqualS` (sys <> sxs)
tests_monoid :: Test
tests_monoid = testGroup "Monoid Instance"
[ testProperty "update equivalence" prop_monoid_update_equiv
, testProperty "associativity" prop_monoid_assoc
, testProperty "commutativity" prop_monoid_commute
]
------------------------------- Utility functions ---------------------------
probsFromWeights :: forall b. Fractional b => [b] -> [b]
probsFromWeights ws = let
w = sum ws
ps = map (/w) ws
in ps
approxEqualS :: Summary -> Summary -> Bool
approxEqualS a b =
S.size a == S.size b &&
all eq [ S.min, S.max, S.mean, S.variance ]
where
eq f = f a ~== f b
------------------------------- Test generators -----------------------------
posInt :: Gen Int
posInt = do
n <- arbitrary
return $! abs n + 1
weight :: Gen Double
weight = do
w <- liftM abs arbitrary
if w < infty then return w else weight
where
infty = 1/0
weights :: Int -> Gen [Double]
weights n = do
ws <- replicateM n weight
if not (all (== 0) ws) then return ws else return $ replicate n 1.0
unif :: Gen Double
unif = do
u <- choose (0,1)
if u == 1 then return 0 else return u
data Weights = Weights Int [Double] deriving Show
instance Arbitrary Weights where
arbitrary = do
n <- choose (1, 500)
ws <- weights n
return $ Weights n ws
data Unif = Unif Double deriving Show
instance Arbitrary Unif where
arbitrary = liftM Unif unif
main :: IO ()
main = defaultMain [ tests_Walker, tests_monoid ]