dawg-0.7.1: Directed acyclic word graphs

Safe HaskellNone



Internal representation of the Data.DAWG automaton. Names in this module correspond to a graphical representation of automaton: nodes refer to states and edges refer to transitions.



data Graph a Source

A set of nodes. To every node a unique identifier is assigned. Invariants:

  • freeIDs \intersection occupiedIDs = \emptySet,
  • freeIDs \sum occupiedIDs = {0, 1, ..., |freeIDs \sum occupiedIDs| - 1},

where occupiedIDs = elemSet idMap.

TODO: Is it possible to merge freeIDs with ingoMap to reduce the memory footprint?




idMap :: !(Map (Node a) ID)

Map from nodes to IDs.

freeIDs :: !IntSet

Set of free IDs.

nodeMap :: !(IntMap (Node a))

Map from IDs to nodes.

ingoMap :: !(IntMap Int)

Number of ingoing paths (different paths from the root to the given node) for each node ID in the graph. The number of ingoing paths can be also interpreted as a number of occurences of the node in a tree representation of the graph.


Eq a => Eq (Graph a) 
(Eq (Graph a), Ord a) => Ord (Graph a) 
Show a => Show (Graph a) 
(Ord a, Binary a) => Binary (Graph a) 

empty :: Graph aSource

Empty graph.

size :: Graph a -> IntSource

Size of the graph (number of nodes).

nodeBy :: ID -> Graph a -> Node aSource

Node with the given identifier.

nodeID :: Ord a => Node a -> Graph a -> IDSource

Retrieve the node identifier.

insert :: Ord a => Node a -> Graph a -> (ID, Graph a)Source

Insert node into the graph. If the node was already a member of the graph, just increase the number of ingoing paths. NOTE: Number of ingoing paths will not be changed for any descendants of the node, so the operation alone will not ensure that properties of the graph are preserved.

delete :: Ord a => Node a -> Graph a -> Graph aSource

Delete node from the graph. If the node was present in the graph at multiple positions, just decrease the number of ingoing paths. NOTE: The function does not delete descendant nodes which may become inaccesible nor does it change the number of ingoing paths for any descendant of the node.