fix spelling of Petersen graph

Author: larskuhtz

src/Data/DiGraph.hs

@@ -80,6 +80,7 @@ module Data.DiGraph
 , diCycle
 , line
 , diLine
+, petersenGraph
 , petersonGraph
 , twentyChainGraph
 , hoffmanSingleton
@@ -540,15 +541,15 @@ diLine n = unsafeFromList [ (a, [ a + 1 | a /= int n - 1]) | a <- [0 .. int n -
 line :: Natural -> DiGraph Int
 line = symmetric . diLine
 
--- | The Peterson graph.
+-- | The Petersen graph.
 --
 -- * order: 10
 -- * size: 30
 -- * degree: 3
 -- * diameter: 2
 --
-petersonGraph :: DiGraph Int
-petersonGraph = DiGraph
+petersenGraph :: DiGraph Int
+petersenGraph = DiGraph
     [ (0, [2,3,5])
     , (1, [3,4,6])
     , (2, [4,0,7])
@@ -561,6 +562,10 @@ petersonGraph = DiGraph
     , (9, [4,8,5])
     ]
 
+petersonGraph :: DiGraph Int
+petersonGraph = petersenGraph
+{-# DEPRECATED petersonGraph "Use petersenGraph instead" #-}
+
 -- | The "twenty chain" graph.
 --
 -- * order: 20

test/Data/DiGraph/Test.hs

@@ -62,16 +62,16 @@ properties_singletonGraph = prefixProperties "singletonGraph: "
   where
     g = singleton
 
-properties_petersonGraph :: [(String, Property)]
-properties_petersonGraph = prefixProperties "petersonGraph: "
+properties_petersenGraph :: [(String, Property)]
+properties_petersenGraph = prefixProperties "petersenGraph: "
     $ ("order == 10", order g === 10)
     : ("size == 15", symSize g === 15)
     : ("outDegree == 3", maxOutDegree g === 3)
     : ("isRegular", property $ isRegular g)
     : ("diameter == 2", diameter g === Just 2)
     : properties_undirected g
   where
-    g = petersonGraph
+    g = petersenGraph
 
 properties_twentyChainGraph :: [(String, Property)]
 properties_twentyChainGraph = prefixProperties "twentyChainGraph: "
@@ -179,7 +179,7 @@ properties = (concat :: [[(String, Property)]] -> [(String, Property)])
     [ properties_emptyGraph 0
     , properties_emptyGraph 2
     , properties_singletonGraph
-    , properties_petersonGraph
+    , properties_petersenGraph
     , properties_twentyChainGraph
     , properties_hoffmanSingletonGraph
     , properties_pentagon