pyddlib package

Submodules

pyddlib.add module

class pyddlib.add.ADD(index, low, high, value)

Bases: pyddlib.dd.DD

Reduced Ordered Algebraic Decision Diagram class.

Parameters:

• index (int) – root vertex variable index (-1 if terminal vertex)
• low (pyddlib.ADD) – low child vertex of ADD (None if terminal vertex)
• high (pyddlib.ADD) – high child vertex of ADD (None if terminal vertex)
• value – terminal numeric value (None if non-terminal vertex)

classmethod constant(value)

Return a terminal node with a given numeric value.

Parameters:value (Number) – numeric value Return type:pyddlib.ADD

index

Return variable index of node.

Return type:int

is_constant()

Return True if ADD function represents a constant value. Otherwise, return False.

Return type:bool

is_terminal()

Return True if ADD function represents a constant value. Otherwise, return False.

Return type:bool

is_variable()

Return True if ADD function represents the function of a single boolean variable. Otherwise, return False.

Return type:bool

marginalize(variable)

Compute a new reduced ADD with variable marginalized. Return self.restrict({variable.index: 1}) + self.restrict({variable.index: 0})

Parameters:variable – ADD variable node Return type:pyddlib.ADD

classmethod terminal(value)

Return a terminal node with a given numeric value.

Parameters:value (Number) – numeric value Return type:pyddlib.ADD

value

Return node value.

Return type:Number or None

classmethod variable(index)

Return the ADD representing the function of a single boolean variable with given index.

Parameters:index (int) – variable index Return type:pyddlib.ADD

pyddlib.bdd module

class pyddlib.bdd.BDD(index, low, high, value)

Bases: pyddlib.dd.DD

Reduced Ordered Binary Decision Diagram class.

Parameters:

• index (int) – root vertex variable index (-1 if terminal vertex)
• low (pyddlib.BDD) – low child vertex of BDD (None if terminal vertex)
• high (pyddlib.BDD) – high child vertex of BDD (None if terminal vertex)
• value – terminal boolean value (None if non-terminal vertex)

is_one()

Return True if BDD function represents boolean value True. Otherwise, return False.

Return type:bool

is_terminal()

Return True if BDD function represents a constant value. Otherwise, return False.

Return type:bool

is_variable()

Return True if BDD function represents the function of a single boolean variable. Otherwise, return False.

Return type:bool

is_zero()

Return True if BDD function represents boolean value False. Otherwise, return False.

Return type:bool

classmethod one()

Return the BDD representing the constant function True.

Return type:pyddlib.BDD

classmethod terminal(value)

Return a terminal node with a given boolean value.

Parameters:value (bool) – True or False Return type:pyddlib.BDD

classmethod variable(index)

Return the BDD representing the function of a single boolean variable with given index.

Parameters:index (int) – variable index Return type:pyddlib.BDD

classmethod zero()

Return the BDD representing the constant function False.

Return type:pyddlib.BDD

pyddlib.dd module

class pyddlib.dd.DD

Bases: object

Decision Diagram abstract base class.

classmethod apply(v1, v2, op)

Return a new canonical representation of the pyddlib.DD object for the result of v1 op v2.

Parameters:

• v1 (pyddlib.DD) – root vertex of left operand
• v2 (pyddlib.DD) – root vertex of right operand
• op (callable object or function) – a binary operator

Return type:

pyddlib.DD

reduce()

Reduce in place a pyddlib.DD object rooted in self by removing duplicate nodes and redundant sub-trees. Return the canonical representation of the pyddlib.DD object.

Return type:pyddlib.DD

restrict(valuation)

Return a new reduced ADD with variables in valuation.keys() restricted to valuation.values().

Parameters:valuation (dict(int,bool)) – mapping from variable index to boolean value Return type:pyddlib.ADD

Module contents