Clarification of some functions' role

The `filterNodes` function's name and type signature were confusing, so
they were changed to make it evident that the filtering function for an
antry is applied to its total number of cooccurrences.

src/Gargantext/Core/Text/Metrics/Count.hs

@@ -138,11 +138,11 @@ occurrences = occurrencesOn _terms_stem
 -- Note: Compared to `occurences`, this is the more elementary function, maybe
 -- it would make more sense to rename this one into `occurences` and the other
 -- into something more descriptive
-countOccurrences :: (Foldable f, Ord a, Num n)
-                 => f a     -- ^ The collection whose items will be counted
-                 -> Map a n -- ^ A map whose keys are items of the input
-                            -- collection, and whose values are the number of
-                            -- times those items appear in the input collection
+countOccurrences :: (Foldable f, Ord a)
+                 => f a       -- ^ The collection whose items will be counted
+                 -> Map a Int -- ^ A map whose keys are items of the input
+                              -- collection, and whose values are the number of
+                              -- times those items appear in the input collection
 countOccurrences collection =
   foldl' (\occurenceMap item -> insertWith (+) item 1 occurenceMap)
          empty

src/Gargantext/Core/Viz/Graph/Tools.hs

@@ -33,7 +33,7 @@ import Gargantext.Core.Viz.Graph.Bridgeness (bridgeness, nodeId2comId, setNodes2
 import Gargantext.Core.Viz.Graph.Index (createIndices, toIndex, map2mat, mat2map, Index, MatrixShape(..))
 import Gargantext.Core.Viz.Graph.Tools.IGraph (mkGraphUfromEdges, spinglass)
 import Gargantext.Core.Viz.Graph.Types (Attributes(..), BridgenessMethod, Edge(..), Graph(..), MultiPartite(..), Node(..), Partite(..), Strength(..), LegendField(..))
-import Gargantext.Core.Viz.Graph.Utils (edgesFilter, nodesFilter)
+import Gargantext.Core.Viz.Graph.Utils (edgesFilter, filterNodesByCount)
 import Gargantext.Prelude
 import Graph.BAC.ProxemyOptim qualified as BAC
 import Graph.Types (ClusterNode(..))
@@ -189,7 +189,7 @@ data2graph multi labels' occurences bridge conf partitions =
             ]
     -- Remove vertices not connected to any other node, i.e. vertices that have
     -- zero edge joining them to other vertices
-    (bridge', toKeep) = nodesFilter (> 0) bridge
+    (bridge', toKeep) = filterNodesByCount (> 0) bridge
 
     edges = [ Edge { edge_source = show s
                    , edge_hidden = Nothing

src/Gargantext/Core/Viz/Graph/Utils.hs

@@ -81,8 +81,17 @@ edgesFilter m = Map.fromList $ catMaybes results
     keys    = Set.toList $ Set.fromList (x <> y)
     (x,y)   = unzip $ Map.keys m
 
-nodesFilter :: (Show a, Show b, Ord a, Ord b, Num b) => (b -> Bool) -> Map (a,a) b -> (Map (a,a) b, Set a)
-nodesFilter f m = (m', toKeep)
+-- | Filter nodes depending on how many times they (co)occur.
+-- More specifically, for a given value `x :: a`, this sums all entries in the
+-- map that have `x` as a value, and then it filters by applying `f` to the sum.
+-- Warning: This counts the value at `(x, x)` twice.
+filterNodesByCount :: (Show node, Ord node)
+                   => (Int -> Bool) -- ^ Filtering function
+                   -> Map (node, node) b   -- ^ Input map
+                   -> (Map (node, node) b, Set node)
+                   -- ^ The map without the filtered out nodes, and the set of
+                   -- remaining nodes
+filterNodesByCount f m = (m', toKeep)
   where
     m' = Map.filterWithKey (\(a,b) _ -> Set.member a toKeep && Set.member b toKeep) m
     toKeep = Set.fromList