distribution 1.0.1.0 → 1.1.0.0

raw patch · 5 files changed

+105/−42 lines, 5 filesdep ~MonadRandomPVP ok

version bump matches the API change (PVP)

Dependency ranges changed: MonadRandom

API changes (from Hackage documentation)

Files

• Data/Distribution.hs +7/−1
• Data/Distribution/Core.hs +41/−38
• Data/Distribution/Monadic.hs +52/−0
• Data/Distribution/Sample.hs +1/−1
• distribution.cabal +4/−2

@@ -43,6 +43,10 @@       -- | The "Data.Distribution.Sample" module provides ways to efficiently       --   randomly sample values from distributions. +    , module Data.Distribution.Monadic+      -- | The "Data.Distribution.Monadic" module provides a monadic interface+      --   to build distributions.+       -- * Other modules        -- | Not all modules related to distributions are exported by default.@@ -169,7 +173,9 @@  import System.Random (mkStdGen)  -- For doctest. +import Data.Distribution.Aggregator import Data.Distribution.Core import Data.Distribution.Measure-import Data.Distribution.Aggregator+import Data.Distribution.Monadic import Data.Distribution.Sample+

@@ -36,14 +36,16 @@     , select     , assuming       -- ** Combination-    , combine+    , combineWith       -- ** Sequences       -- *** Independant experiments     , trials     , times+    , iid       -- *** Dependant experiments     , andThen-    , on+      -- ** Utilities+    , isValid     ) where  import Control.Arrow (second)@@ -134,15 +136,15 @@     abs = select abs     signum = select signum     negate = select negate-    d1 + d2 = d1 `andThen` (+) `on` d2-    d1 - d2 = d1 `andThen` (-) `on` d2-    d1 * d2 = d1 `andThen` (*) `on` d2+    d1 + d2 = combineWith (+) d1 d2+    d1 - d2 = combineWith (-) d1 d2+    d1 * d2 = combineWith (*) d1 d2  -- Binary operations on distributions are defined to -- be the binary operation on each pair of elements. instance (Ord a, Fractional a) => Fractional (Distribution a) where     fromRational = always . fromRational-    d1 / d2 = d1 `andThen` (/) `on` d2+    d1 / d2 = combineWith (+) d1 d2     recip = select recip  -- Binary operations on distributions are defined to@@ -152,8 +154,8 @@     exp = select exp     sqrt = select sqrt     log = select log-    d1 ** d2 = d1 `andThen` (**) `on` d2-    d1 `logBase` d2 = d1 `andThen` logBase `on` d2+    d1 ** d2 = combineWith (**) d1 d2+    d1 `logBase` d2 = combineWith logBase d1 d2     sin = select sin     tan = select tan     cos = select cos@@ -169,7 +171,7 @@  instance (Ord a, Monoid a) => Monoid (Distribution a) where     mempty = always mempty-    mappend d1 d2 = d1 `andThen` mappend `on` d2+    mappend d1 d2 = combineWith mappend d1 d2  -- | Converts the distribution to a list of increasing values whose probability --   is greater than @0@. To each value is associated its probability.@@ -257,7 +259,7 @@ --   >>> assuming (> 2) $ uniform [1 .. 6] --   fromList [(3,1 % 4),(4,1 % 4),(5,1 % 4),(6,1 % 4)] -----   Note that the resulting distribution will be empty+--   Note that the resulting distribution will be invalid --   if the predicate does not hold on any of the values. -- --   >>> assuming (> 7) $ uniform [1 .. 6]@@ -272,25 +274,12 @@  -- Combination ---- | Combines multiple weighted distributions into a single distribution.------   The probability of each element is the weighted sum of the element's---   probability in every distribution.------   >>> combine [(always 2, 1 / 3), (uniform [1..6], 2 / 3)]---   fromList [(1,1 % 9),(2,4 % 9),(3,1 % 9),(4,1 % 9),(5,1 % 9),(6,1 % 9)]------   Note that the weights do not have to sum up to @1@. Distributions with---   negative or null weight will be ignored.-combine :: (Ord a, Real p) => [(Distribution a, p)] -> Distribution a-combine dws = Distribution $ Map.unionsWith (+) $ zipWith go ds ps-  where-    (ds, ws) = unzip $ filter ((> 0) . snd) $ map (second toRational) dws-    w = sum ws-    ps = map (/ w) ws-    go (Distribution xs) p = fmap (* p) xs-+combineWith :: (Ord b) => (a -> a -> b) -> Distribution a -> Distribution a -> Distribution b+combineWith f (Distribution xs) (Distribution ys) = Distribution $ Map.unionsWith (+) $ do+    (x, p) <- Map.toList xs+    return $ Map.fromListWith (+) $ do+        (y, q) <- Map.toList ys+        return (f x y, p * q)  -- Sequences @@ -363,13 +352,29 @@             let p' = 2 * p * q             return (y + x, p') +iid :: (Ord a) => (a -> a -> a) -> Int -> Distribution a -> Distribution a+iid f n d+    | n <= 0 = error "Called iid with a non-positive number of trials."+    | otherwise = go n+    where+      go 1 = d+      go m =+        let (i, j) = quotRem m 2 +            sub = go i+            combined = combineWith f sub sub+        in if j == 0+          then combined+          else combineWith f combined d++ -- | Computes for each value in the distribution a new distribution, and then --   combines those distributions, giving each the weight of the original value. -- --   >>> uniform [1 .. 3] `andThen` (\ n -> uniform [1 .. n]) --   fromList [(1,11 % 18),(2,5 % 18),(3,1 % 9)] -----   See the 'on' function for a convenient way to chain distributions.+--   See the 'Experiment' data type in the 'Data.Distribution.Monadic' module+--   for a more "natural" monadic interface.  infixl 7 `andThen` andThen :: Ord b => Distribution a -> (a -> Distribution b) -> Distribution b andThen (Distribution xs) f = Distribution $@@ -377,12 +382,10 @@   where     go (x, p) = fmap (* p) $ toMap $ f x --- | Utility to partially apply a function on a distribution.---   A use case for 'on' is to use it in conjunction with 'andThen'---   to combine distributions.++-- | Determines if a distribution is valid. -----   >>> uniform [1 .. 3] `andThen` (+) `on` uniform [1 .. 2]---   fromList [(2,1 % 6),(3,1 % 3),(4,1 % 3),(5,1 % 6)]-infixl 8 `on`-on :: Ord c => (a -> b -> c) -> Distribution b -> a -> Distribution c-on f d x = select (f x) d+--   A distribution is valid if and only if its domain is non-empty.+--   Invalid distributions may arise from the use of 'assuming' for instance.+isValid :: Distribution a -> Bool+isValid (Distribution xs) = not $ Map.null xs

@@ -0,0 +1,52 @@+{-# LANGUAGE GADTs #-}++{- Copyright 2016 Romain Edelmann++   Licensed under the Apache License, Version 2.0 (the "License");+   you may not use this file except in compliance with the License.+   You may obtain a copy of the License at++       http://www.apache.org/licenses/LICENSE-2.0++   Unless required by applicable law or agreed to in writing, software+   distributed under the License is distributed on an "AS IS" BASIS,+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.+   See the License for the specific language governing permissions and+   limitations under the License. -}++-- | This modules provides a monadic interface to build distributions.+module Data.Distribution.Monadic +    ( Experiment, from, run ) where++import Data.Distribution.Core++-- | Monadic description of distributions.+data Experiment a where+  Return :: a -> Experiment a+  Bind :: Experiment b -> (b -> Experiment a) -> Experiment a+  Prim :: (Ord a) => Distribution a -> Experiment a++instance Functor Experiment where+  fmap f d = Bind d (\ x -> Return (f x))++instance Applicative Experiment where+  pure x = Return x+  df <*> d = Bind df (\ f -> Bind d (\ x -> Return (f x)))++instance Monad Experiment where+  return x = Return x+  d >>= f = Bind d f++-- | Converts a concrete distribution into its+--   monadic representation.+from :: (Ord a) => Distribution a -> Experiment a+from d = Prim d++-- | Converts the monadic description of the distribution +--   to a concrete distribution.+run :: (Ord a) => Experiment a -> Distribution a+run (Return x) = always x+run (Bind (Return x) f) = run (f x)+run (Bind (Bind i g) f) = run (Bind i (\ x -> Bind (g x) f))+run (Bind (Prim d) f) = d `andThen` \ x -> run (f x)+run (Prim d) = d

@@ -176,8 +176,8 @@ getSample :: MonadRandom m => Generator a -> m a getSample g = do     let n = capacity g-    u <- getRandom     j <- getRandomR (0, n - 1)+    u <- getRandom     let i = if u < probabilities g ! j                 then j                 else indexes g ! j

@@ -8,7 +8,7 @@ -- PVP summary:      +-+------- breaking API changes --                   | | +----- non-breaking API additions --                   | | | +--- code changes with no API change-version:             1.0.1.0+version:             1.1.0.0  -- A short (one-line) description of the package. synopsis:             Finite discrete probability distributions.@@ -51,8 +51,10 @@                        Data.Distribution.Domain.Coin,                        Data.Distribution.Domain.Dice,                        Data.Distribution.Measure,+                       Data.Distribution.Monadic,                        Data.Distribution.Sample +   -- Modules included in this library but not exported.   -- other-modules: @@ -60,6 +62,6 @@   build-depends:       array >=0.4,                        base >=4.5 && <5,                        containers ==0.5.*,-                       MonadRandom ==0.4.*,+                       MonadRandom >=0.4,                        random ==1.1.*