genRange should be constant for a RandomGen - enforce this with types

Benchmark/Makefile

@@ -1,7 +1,6 @@
 
 
-#OPTS= -O2 -Wall -XCPP
-OPTS= -O2 -Wall -XCPP -Werror
+OPTS= -O2 -Wall -XCPP
 
 all: lib bench
 

Benchmark/RandomnessTest2.hs

@@ -0,0 +1,42 @@
+module Main where
+
+import Control.Monad
+import System.Random
+
+-- splitN :: (RandomGen g) => Int -> g -> ([g], g)
+splitN 0 g = ([], g)
+splitN n g = (g1:l, g')
+  where
+  (l, g') = splitN (n-1) g2
+  (g1, g2) = split g
+
+-- The funny splitting operation.
+split' :: (RandomGen g) => g -> (g, g)
+split' g = (g12, g21)
+  where
+  (g1, g2) = split g
+  (_, g12) = split g1
+  (g21, _) = split g2
+
+-- This test checks if generators created by calling split 2 times are independent.
+-- It generates pairs of integers from 0 to n-1, using split' to
+-- generate both numbers using one seed. Then it counts how often the
+-- two numbers are equal.
+test :: (RandomGen g) => Int -> Int -> g -> Int
+test numTests n g = equals
+  where
+  (gs, _) = splitN numTests g
+  equals = count id $ map single gs
+  count p l = length $ filter p l
+  single g' = (fst $ randomR (0, n-1) g1) == (fst $ randomR (0, n-1) g2)
+    where
+    (g1, g2) = split' g'
+
+main = do
+  let g = mkStdGen 42
+  forM_ [2..15] $ \i -> do
+    let actual = test (i * 1000) i g
+    putStrLn $ "Generated " ++ show (i * 1000)
+      ++ " pairs of numbers from 0 to " ++ show (i - 1)
+      ++ " -- " ++ show actual ++ " pairs contained equal numbers "
+      ++ "and we expected about 1000."

Benchmark/RandomnessTest3.hs

@@ -0,0 +1,43 @@
+module Main where
+
+import Control.Monad
+import System.Random.TF.Gen
+import System.Random.TF.Instances
+
+splitN :: (RandomGen g) => Int -> g -> ([g], g)
+splitN 0 g = ([], g)
+splitN n g = (g1:l, g')
+  where
+  (l, g') = splitN (n-1) g2
+  (g1, g2) = split g
+
+-- The funny splitting operation.
+split' :: (RandomGen g) => g -> (g, g)
+split' g = (g12, g21)
+  where
+  (g1, g2) = split g
+  (_, g12) = split g1
+  (g21, _) = split g2
+
+-- This test checks if generators created by calling split 2 times are independent.
+-- It generates pairs of integers from 0 to n-1, using split' to
+-- generate both numbers using one seed. Then it counts how often the
+-- two numbers are equal.
+test :: (RandomGen g) => Int -> Int -> g -> Int
+test numTests n g = equals
+  where
+  (gs, _) = splitN numTests g
+  equals = count id $ map single gs
+  count p l = length $ filter p l
+  single g' = (fst $ randomR (0, n-1) g1) == (fst $ randomR (0, n-1) g2)
+    where
+    (g1, g2) = split' g'
+
+main = do
+  let g = seedTFGen (42, 42, 42, 42)
+  forM_ [2..15] $ \i -> do
+    let actual = test (i * 1000) i g
+    putStrLn $ "Generated " ++ show (i * 1000)
+      ++ " pairs of numbers from 0 to " ++ show (i - 1)
+      ++ " -- " ++ show actual ++ " pairs contained equal numbers "
+      ++ "and we expected about 1000."

Benchmark/SimpleRNGBench.hs

@@ -33,6 +33,7 @@ import Prelude  hiding (last,sum)
 import BinSearch
 
 #ifdef TEST_COMPETITORS
+import System.Random.TF
 import System.Random.Mersenne.Pure64
 import System.Random.MWC
 import Control.Monad.Primitive
@@ -44,11 +45,11 @@ import GHC.IO
 -- Miscellaneous helpers:
 
 -- Readable large integer printing:
-commaint :: Integral a => a -> String
+commaint :: (Show a, Integral a) => a -> String
 commaint n = 
    reverse $ concat $
    intersperse "," $ 
-   chunk 3 $ 
+   chunksOf 3 $ 
    reverse (show n)
 
 padleft :: Int -> String -> String
@@ -281,7 +282,13 @@ main = do
 	 timeit th freq "System.Random.Mersenne.Pure64 Ints"   gen_mt randInt2
 	 timeit th freq "System.Random.Mersenne.Pure64 Floats" gen_mt randFloat2
 
---	 gen_mwc <- create
+         let gen_tf = seedTFGen (0,1,2,3)
+             randInt4   = random :: RandomGen g => g -> (Int,g)
+	     randFloat4 = random :: RandomGen g => g -> (Float,g)
+         timeit th freq "System.Random.TF next" gen_tf next
+	 timeit th freq "System.Random.TF Ints"   gen_tf randInt4
+	 timeit th freq "System.Random.TF Floats" gen_tf randFloat4
+
          withSystemRandom $ \ gen_mwc -> do
 	    let randInt3   = random :: RandomGen g => g -> (Int,g)
 		randFloat3 = random :: RandomGen g => g -> (Float,g)

README.md

@@ -10,7 +10,7 @@ The API documentation can be found here:
 
 A module supplying this interface is required for Haskell 98 (but not Haskell
 2010). An older [version]
-(http://www.haskell.org/ghc/docs/latest/html/libraries/haskell98/Random.html)
+(https://downloads.haskell.org/~ghc/latest/docs/html/libraries/haskell98-2.0.0.3/Random.html)
 of this library is included with GHC in the haskell98 package. This newer
 version, with compatible api, is included in the [Haskell Platform]
 (http://www.haskell.org/platform/contents.html).