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Fix DFA minimization

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I assumed bijectivty between behaviours and equivalence groups, but
there was no bijectivity.
This commit is contained in:
Joscha 2019-11-01 00:54:17 +00:00
parent 764fffa1ca
commit 3b8e2fcbf9
1 changed files with 9 additions and 10 deletions
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19
src/Rextra/Automaton.hs
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@ -119,28 +119,28 @@ groupByBehaviour mapping = groupByFirst . map (\s -> (mapping Map.! s, s)) . Set
groupAllByBehaviour :: (Ord s, Ord t) groupAllByBehaviour :: (Ord s, Ord t)
=> Map.Map s (Behaviour s t) => Map.Map s (Behaviour s t)
-> Partition s -> Partition s
-> Map.Map (Behaviour s t) (EquivalenceGroup s) -> Map.Map (EquivalenceGroup s) (Behaviour s t)
groupAllByBehaviour mapping = Map.unions . map (groupByBehaviour mapping) . Set.toList groupAllByBehaviour mapping = Map.fromList
. map swap
. concatMap (Map.assocs . groupByBehaviour mapping)
. Set.toList
findNewBehaviourGrouping :: (Ord s, Ord t) findNewBehaviourGrouping :: (Ord s, Ord t)
=> Map.Map s (Dfa.State s t) => Map.Map s (Dfa.State s t)
-> Partition s -> Partition s
-> Map.Map (Behaviour s t) (EquivalenceGroup s) -> Map.Map (EquivalenceGroup s) (Behaviour s t)
findNewBehaviourGrouping statemap partition = findNewBehaviourGrouping statemap partition =
let mapping = partitionToMap partition let mapping = partitionToMap partition
behaviours = findBehaviours mapping statemap behaviours = findBehaviours mapping statemap
in groupAllByBehaviour behaviours partition in groupAllByBehaviour behaviours partition
groupingToPartition :: (Ord s) => Map.Map (Behaviour s t) (EquivalenceGroup s) -> Partition s
groupingToPartition = Set.fromList . Map.elems
findGroupingFixpoint :: (Ord s, Ord t) findGroupingFixpoint :: (Ord s, Ord t)
=> Map.Map s (Dfa.State s t) => Map.Map s (Dfa.State s t)
-> Partition s -> Partition s
-> Map.Map (Behaviour s t) (EquivalenceGroup s) -> Map.Map (EquivalenceGroup s) (Behaviour s t)
findGroupingFixpoint statemap partition = findGroupingFixpoint statemap partition =
let newGrouping = findNewBehaviourGrouping statemap partition let newGrouping = findNewBehaviourGrouping statemap partition
newPartition = groupingToPartition newGrouping newPartition = Map.keysSet newGrouping
in if partition == newPartition in if partition == newPartition
then newGrouping then newGrouping
else findGroupingFixpoint statemap newPartition else findGroupingFixpoint statemap newPartition
@ -154,7 +154,6 @@ minimizeDfa :: (Ord s, Ord t) => Dfa.Dfa s t -> Dfa.Dfa (EquivalenceGroup s) t
minimizeDfa a = minimizeDfa a =
let grouping = findGroupingFixpoint (stateMap a) (initialPartition a) let grouping = findGroupingFixpoint (stateMap a) (initialPartition a)
mapping = partitionToMap $ groupingToPartition grouping mapping = partitionToMap $ groupingToPartition grouping
newStateMap = Map.fromList $ map swap $ Map.assocs grouping
newEntryState = mapping Map.! entryState a newEntryState = mapping Map.! entryState a
newExitStates = Set.map (mapping Map.!) (exitStates a) newExitStates = Set.map (mapping Map.!) (exitStates a)
in fromJust $ fa newStateMap newEntryState newExitStates in fromJust $ fa grouping newEntryState newExitStates