OBDD.Data

implementation of reduced ordered binary decision diagrams.

the data type

data OBDD v

assumes total ordering on variables

size :: OBDD v -> Index

for external use

null :: OBDD v -> Bool

does the OBDD not have any models?

satisfiable :: OBDD v -> Bool

does the OBDD have any models?

number_of_models :: Ord v => Set v -> OBDD v -> Integer

Number of satisfying assignments with given set of variables. The set of variables must be given since the current OBDD may not contain all variables that were used to construct it, since some nodes may have been removed because they had identical children.

some_model :: Ord v => OBDD v -> IO (Maybe (Map v Bool))

randomly select one model, if possible

all_models :: Ord v => OBDD v -> [Map v Bool]

list of all models (WARNING not using variables that had been deleted)

fold :: Ord v => (Bool -> a) -> (v -> a -> a -> a) -> OBDD v -> a

Apply function in each node, bottom-up. return the value in the root node. Will cache intermediate results. You might think that count_models = fold (b -> if b then 1 else 0) (v l r -> l + r) but that's not true because a path might omit variables. Use full_fold to fold over interpolated nodes as well.

foldM :: (Monad m, Ord v) => (Bool -> m a) -> (v -> a -> a -> m a) -> OBDD v -> m a

Run action in each node, bottum-up. return the value in the root node. Will cache intermediate results.

full_fold :: Ord v => Set v -> (Bool -> a) -> (v -> a -> a -> a) -> OBDD v -> a

Apply function in each node, bottom-up. Also apply to interpolated nodes: when a link from a node to a child skips some variables: for each skipped variable, we run the branch function on an interpolated node that contains this missing variable, and identical children. With this function, number_of_models can be implemented as full_fold vars (bool 0 1) ( const (+) ). And it actually is, see the source.

full_foldM :: (Monad m, Ord v) => Set v -> (Bool -> m a) -> (v -> a -> a -> m a) -> OBDD v -> m a

toDot :: Show v => OBDD v -> String

toDot outputs a string in format suitable for input to the "dot" program from the graphviz suite.

display :: Show v => OBDD v -> IO ()

Calls the dot executable (must be in $PATH) to draw a diagram in an X11 window. Will block until this window is closed. Window can be closed gracefully by typing q when it has focus.

for internal use

data Node v i

Constructors

Leaf !Bool

Branch !v !i !i

Instances

(Eq i, Eq v) => Eq (Node v i)

Methods

(==) :: Node v i -> Node v i -> Bool

(/=) :: Node v i -> Node v i -> Bool

(Ord i, Ord v) => Ord (Node v i)

Methods

compare :: Node v i -> Node v i -> Ordering

(<) :: Node v i -> Node v i -> Bool

(<=) :: Node v i -> Node v i -> Bool

(>) :: Node v i -> Node v i -> Bool

(>=) :: Node v i -> Node v i -> Bool

max :: Node v i -> Node v i -> Node v i

min :: Node v i -> Node v i -> Node v i

make :: State (OBDD v) Index -> OBDD v

register :: Ord v => Node v Index -> State (OBDD v) Index

checked_register :: Ord v => Node v Index -> State (OBDD v) Index

cached :: Ord v => (Index, Index) -> State (OBDD v) Index -> State (OBDD v) Index

top :: OBDD v -> Index

access :: OBDD v -> Node v (OBDD v)