[READ] cosmetics

src/Data/Graph/Clustering/FLouvain.hs

@@ -24,8 +24,11 @@ no further improvement can be achieved and the first phase is then
 complete.
 
 Reference:
-Blondel, Vincent D; Guillaume, Jean-Loup; Lambiotte, Renaud; Lefebvre, Etienne (9 October 2008). "Fast unfolding of communities in large networks". Journal of Statistical Mechanics: Theory and Experiment. 2008 (10): P10008. arXiv:0803.0476 Freely accessible. doi:10.1088/1742-5468/2008/10/P10008.
- 
+Blondel, Vincent D; Guillaume, Jean-Loup; Lambiotte, Renaud;
+Lefebvre, Etienne (9 October 2008). "Fast unfolding of communities
+in large networks". Journal of Statistical Mechanics: Theory and
+Experiment. 2008 (10): P10008. arXiv:0803.0476 Freely accessible.
+doi:10.1088/1742-5468/2008/10/P10008.
 
 -}
 
@@ -48,16 +51,21 @@ data ClusteringMethod = Glue | Klue
   deriving (Eq)
 
 
+------------------------------------------------------------------------
+-- | Specific FGL needed functions
+
 -- | Find LNode of a node (i.e. a node with label)
 lnode :: (Graph gr) => gr a b -> Node -> Maybe (LNode a)
 lnode cgr n = case lab cgr n of
   Nothing -> Nothing
   Just l  -> Just (n, l)
 
--- We need to implement a fold over graph
+-- | Fold over graph definitions: type and function
 
+-- | Fold over graph type
 type CFunFold a b c = Context a b -> c -> c
 
+-- | Fold over graph function
 xdfsFoldWith :: (Graph gr)
     => CFun     a b [Node]
     -> CFunFold a b c
@@ -67,10 +75,12 @@ xdfsFoldWith :: (Graph gr)
     -> c
 xdfsFoldWith _ _ acc [] _            = acc
 xdfsFoldWith _ _ acc _ g | isEmpty g = acc
-xdfsFoldWith d f acc (v:vs) g = case match v g of
-                                 (Just c, g')  -> xdfsFoldWith d f (f c acc) (d c++vs) g'
-                                 (Nothing, g') -> xdfsFoldWith d f acc vs g'
+xdfsFoldWith d f acc (v:vs) g =
+  case match v g of
+    (Just c, g')  -> xdfsFoldWith d f (f c acc) (d c++vs) g'
+    (Nothing, g') -> xdfsFoldWith d f acc vs g'
 
+------------------------------------------------------------------------
 
 -- Our basic graph. Nodes have custom labels. Edges have weight assigned to them.
 type FEdge = Double
@@ -106,7 +116,7 @@ iteration gr cs = xdfsFoldWith suc' step cs (nodes gr) gr
 step :: CFunFold a FEdge CGr
 step (p, v, l, s) cgr = cgr
   where
-    mNc  = nodeCommunity v cgr
+    mNc = nodeCommunity  v cgr
     ncs = nodeNeighbours v cgr
     -- We move node from community nc into ncs
     moves :: Maybe (LNode Community, [LNode Community])
@@ -162,30 +172,39 @@ moveNode gr n direction c = moveNodeWithNeighbours lnNeighbors n direction c
     lnNeighbors :: Adj FEdge
     lnNeighbors = lneighbors gr n
 
--- | Same asa 'moveNode' above but with only node neighbours, not whole graph
+-- | Same as 'moveNode' above but with only node neighbours, not whole graph
 moveNodeWithNeighbours :: Adj FEdge -> Node -> Direction -> Community -> Community
-moveNodeWithNeighbours lnNeighbors n direction (Community (ns, inwsum, totwsum)) = Community (newNs, newInWsum, newTotWsum)
-  where
-    newNs = case direction of
-      Into  -> n:ns
-      OutOf -> DL.delete n ns
-    comNeighbors :: Adj FEdge
-    comNeighbors = filter (\ln -> snd ln `elem` ns) lnNeighbors
-    nonComNeighbors :: Adj FEdge
-    nonComNeighbors = filter (\ln -> snd ln `notElem` ns) lnNeighbors
-    -- Update InWeightSum with connections between node and the community
-    sumN :: InWeightSum
-    sumN = sum $ map fst comNeighbors
-    -- Update TotWeightSum, subtracting connections between node and community
-    -- and adding connections of node to non-community
-    sumNonCom :: TotWeightSum
-    sumNonCom = sum $ map fst nonComNeighbors
-    directionN = case direction of
-      Into -> 1
-      OutOf -> -1
-    newInWsum = inwsum + directionN * sumN
-    newTotWsum = totwsum + directionN * (sumN - sumNonCom)
+moveNodeWithNeighbours lnNeighbors n direction (Community (ns, inwsum, totwsum)) =
+  Community (newNs, newInWsum, newTotWsum)
+    where
+
+      newNs = case direction of
+        Into  -> n:ns
+        OutOf -> DL.delete n ns
+
+      newInWsum  = inwsum  + directionN * sumN
+      newTotWsum = totwsum + directionN * (sumN - sumNonCom)
+
+      directionN :: Double
+      directionN = case direction of
+        Into  ->  1
+        OutOf -> -1
+
+      -- Update InWeightSum with connections between node and the community
+      sumN :: InWeightSum
+      sumN = sum $ map fst comNeighbors
+
+      -- Update TotWeightSum, subtracting connections between node and community
+      -- and adding connections of node to non-community
+      sumNonCom :: TotWeightSum
+      sumNonCom = sum $ map fst nonComNeighbors
+
+      -- Node Adj Context
+      comNeighbors    :: Adj FEdge
+      comNeighbors    = filter (\ln -> snd ln `elem`    ns) lnNeighbors
 
+      nonComNeighbors :: Adj FEdge
+      nonComNeighbors = filter (\ln -> snd ln `notElem` ns) lnNeighbors
 
 
 {-