add random generator

ChangeLog.md

 Revision history for haskell-igraph
 ===================================
 
-v0.7.1 -- 2018-XX-XX
+v0.7.2 -- XXXX-XX-XX
+--------------------
+
+* Add random number generator.
+
+v0.7.1 -- 2018-11-26
+--------------------
 
 * Add a few more functions.
 

haskell-igraph.cabal

@@ -30,6 +30,7 @@ library
     IGraph.Internal
     IGraph
     IGraph.Mutable
+    IGraph.Random
     IGraph.Types
     IGraph.Exporter.GEXF
     IGraph.Algorithms

src/IGraph/Algorithms/Generators.chs

@@ -22,6 +22,7 @@ import qualified Foreign.Ptr as C2HSImp
 import Foreign
 
 import           IGraph
+import           IGraph.Random (Gen)
 import           IGraph.Mutable (MGraph(..))
 {#import IGraph.Internal #}
 {#import IGraph.Internal.Constants #}
@@ -86,8 +87,9 @@ data ErdosRenyiModel = GNP Int Double  -- ^ G(n,p) graph, every possible edge is
 erdosRenyiGame :: forall d. SingI d
                => ErdosRenyiModel
                -> Bool  -- ^ self-loop
+               -> Gen
                -> IO (Graph d () ())
-erdosRenyiGame model self = do
+erdosRenyiGame model self _ = do
     igraphInit
     gr <- case model of
         GNP n p -> igraphErdosRenyiGame IgraphErdosRenyiGnp n p directed self
@@ -107,8 +109,9 @@ erdosRenyiGame model self = do
 -- | Generates a random graph with a given degree sequence.
 degreeSequenceGame :: [Int]   -- ^ Out degree
                    -> [Int]   -- ^ In degree
+                   -> Gen
                    -> IO (Graph 'D () ())
-degreeSequenceGame out_deg in_deg = do
+degreeSequenceGame out_deg in_deg _ = do
     igraphInit
     withList out_deg $ \out_deg' ->
         withList in_deg $ \in_deg' -> do
@@ -127,8 +130,9 @@ rewireEdges :: MGraph RealWorld d v e
                         -- one (inclusive).
             -> Bool     -- ^ whether loop edges are allowed in the new graph, or not.
             -> Bool     -- ^ whether multiple edges are allowed in the new graph.
+            -> Gen
             -> IO ()
-rewireEdges gr p loop multi = igraphRewireEdges (_mgraph gr) p loop multi
+rewireEdges gr p loop multi _ = igraphRewireEdges (_mgraph gr) p loop multi
 {#fun igraph_rewire_edges as ^ 
     { `IGraph'
     , `Double'
@@ -140,8 +144,9 @@ rewireEdges gr p loop multi = igraphRewireEdges (_mgraph gr) p loop multi
 rewire :: (Serialize v, Ord v, Serialize e)
        => Int    -- ^ Number of rewiring trials to perform.
        -> Graph d v e
+       -> Gen
        -> IO (Graph d v e)
-rewire n gr = do
+rewire n gr _ = do
     gr' <- thaw gr
     igraphRewire (_mgraph gr') n IgraphRewiringSimple
     unsafeFreeze gr'

src/IGraph/Internal.chs

@@ -115,6 +115,12 @@ module IGraph.Internal
       -- * Igraph arpack options type
     , ArpackOpt
     , allocaArpackOpt
+
+      -- * Random numbers
+    , RNG
+    , igraphRngSetDefault
+    , allocaRng
+    , igraphRngSeed
     ) where
 
 import Control.Monad
@@ -749,3 +755,33 @@ allocaArpackOpt fun = allocaBytes {# sizeof igraph_arpack_options_t #} $ \opt ->
     igraphArpackOptionsInit opt >> fun opt
 {-# INLINE allocaArpackOpt #-}
 {#fun igraph_arpack_options_init as ^ { castPtr `Ptr ArpackOpt' } -> `CInt' void- #}
+
+
+--------------------------------------------------------------------------------
+-- Random numbers
+--------------------------------------------------------------------------------
+
+data RNG
+
+-- | Set the default igraph random number generator.
+{#fun igraph_rng_set_default as ^ { castPtr `Ptr RNG' } -> `()' #}
+
+-- | Allocate and initialize a RNG.
+allocaRng :: (Ptr RNG -> IO a) -> IO a
+allocaRng fun = allocaBytes {# sizeof igraph_rng_t #} $ \rng ->
+    bracket_ (igraphRngInit_ rng) (igraphRngDestroy rng) (fun rng)
+{-# INLINE allocaRng #-}
+
+{#fun igraph_rng_init_ as igraphRngInit_
+    { castPtr `Ptr RNG' } -> `CInt' void- #}
+{#fun igraph_rng_destroy as ^ { castPtr `Ptr RNG' } -> `()' #}
+
+-- | Set the seed of a random number generator
+{#fun igraph_rng_seed as ^
+    { castPtr `Ptr RNG', `Int' } -> `CInt' void- #}
+
+#c
+int igraph_rng_init_(igraph_rng_t *rng) {
+    return(igraph_rng_init(rng, &igraph_rngtype_mt19937));
+}
+#endc

src/IGraph/Random.hs

+module IGraph.Random
+    ( Gen
+    , withSystemRandom
+    , withSeed
+    ) where
+
+import IGraph.Internal
+
+-- | Random number generator
+data Gen = Gen
+
+withSystemRandom :: (Gen -> IO a) -> IO a
+withSystemRandom fun = fun Gen
+{-# INLINE withSystemRandom #-}
+
+withSeed :: Int -> (Gen -> IO a) -> IO a
+withSeed seed fun = allocaRng $ \rng -> do
+    igraphRngSetDefault rng
+    igraphRngSeed rng seed
+    fun Gen
+{-# INLINE withSeed #-}
\ No newline at end of file

stack.yaml

@@ -7,5 +7,5 @@ packages:
 
 extra-deps: []
 
-resolver: nightly-2018-11-24
-#resolver: lts-12.14
+#resolver: nightly-2018-11-24
+resolver: lts-12.14

tests/Test/Algorithms.hs

@@ -11,6 +11,7 @@ import           Test.Tasty
 import           Test.Tasty.HUnit
 
 import           IGraph
+import           IGraph.Random
 import           IGraph.Algorithms
 import qualified IGraph.Mutable      as GM
 
@@ -72,7 +73,7 @@ decomposeTest = testGroup "Decompose"
     [ testCase "ring" $ edges (head $ decompose $ ring 10) @?=
         [(0,1), (1,2), (2,3), (3,4), (4,5), (5,6), (6,7), (7,8), (8,9), (0,9)]
     , testCase "1 component" $ do
-        gr <- erdosRenyiGame (GNP 100 (40/100)) False :: IO (Graph 'U () ())
+        gr <- (withSystemRandom $ erdosRenyiGame (GNP 100 (40/100)) False) :: IO (Graph 'U () ())
         1 @?= length (decompose gr)
     , testCase "toy example" $ map (sort . edges) (decompose gr) @?=
         [ [(0,1), (0,2), (1,2)]

tests/Test/Basic.hs

@@ -13,7 +13,9 @@ import           Test.Tasty.HUnit
 import           Test.Utils
 
 import           IGraph
+import           IGraph.Random
 import qualified IGraph.Mutable    as GM
+import IGraph.Algorithms.Generators
 
 tests :: TestTree
 tests = testGroup "Basic tests"
@@ -21,6 +23,7 @@ tests = testGroup "Basic tests"
     , graphCreationLabeled
     , graphEdit
     , nonSimpleGraphTest
+    , randomGeneratorTest
     ]
 
 graphCreation :: TestTree
@@ -82,3 +85,14 @@ nonSimpleGraphTest = testGroup "loops, multiple edges"
          , ((0,2), 'd') ]
     gr :: Graph 'U Int Char
     gr = mkGraph [0,1,2] es
+
+randomGeneratorTest :: TestTree
+randomGeneratorTest = testGroup "random generator"
+    [ t1 ]
+  where
+    t1 = testCase "random graph" $ do
+        gr1 <- sort . edges <$> genGr 1244
+        gr2 <- sort . edges <$> genGr 1244
+        gr1 @=? gr2
+    genGr :: Int -> IO (Graph 'D () ())
+    genGr seed = withSeed seed $ erdosRenyiGame (GNP 1000 0.5) False