constraint.BacktrackingSolver

Module constraint :: Class BacktrackingSolver

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Type BacktrackingSolver

object --+    
         |    
    Solver --+
             |
            BacktrackingSolver

Problem solver with backtracking capabilities

Examples:

>>> result = [[('a', 1), ('b', 2)],
...           [('a', 1), ('b', 3)],
...           [('a', 2), ('b', 3)]]

>>> problem = Problem(BacktrackingSolver())
>>> problem.addVariables(["a", "b"], [1, 2, 3])
>>> problem.addConstraint(lambda a, b: b > a, ["a", "b"])

>>> solution = problem.getSolution()
>>> sorted(solution.items()) in result
True

>>> for solution in problem.getSolutionIter():
...     sorted(solution.items()) in result
True
True
True

>>> for solution in problem.getSolutions():
...     sorted(solution.items()) in result
True
True
True

Method Summary
	`__init__(self, forwardcheck)`
	`getSolution(self, domains, constraints, vconstraints)` Return one solution for the given problem
	`getSolutionIter(self, domains, constraints, vconstraints)` Return an iterator for the solutions of the given problem
	`getSolutions(self, domains, constraints, vconstraints)` Return all solutions for the given problem
Inherited from object
	`__delattr__(...)` x.__delattr__('name') <==> del x.name
	`__getattribute__(...)` x.__getattribute__('name') <==> x.name
	`__hash__(x)` x.__hash__() <==> hash(x)
	`__new__(T, S, ...)` T.__new__(S, ...) -> a new object with type S, a subtype of T
	`__reduce__(...)` helper for pickle
	`__reduce_ex__(...)` helper for pickle
	`__repr__(x)` x.__repr__() <==> repr(x)
	`__setattr__(...)` x.__setattr__('name', value) <==> x.name = value
	`__str__(x)` x.__str__() <==> str(x)

Method Details

Parameters:: forwardcheck - If false forward checking will not be requested to constraints while looking for solutions (default is true)
(type=bool)

Return one solution for the given problem

Parameters:: domains - Dictionary mapping variables to their domains
(type=dict); constraints - List of pairs of (constraint, variables)
(type=list); vconstraints - Dictionary mapping variables to a list of constraints affecting the given variables.
(type=dict)

Return an iterator for the solutions of the given problem

Parameters:: domains - Dictionary mapping variables to domains
(type=dict); constraints - List of pairs of (constraint, variables)
(type=list); vconstraints - Dictionary mapping variables to a list of constraints affecting the given variables.
(type=dict)

Return all solutions for the given problem

Parameters:: domains - Dictionary mapping variables to domains
(type=dict); constraints - List of pairs of (constraint, variables)
(type=list); vconstraints - Dictionary mapping variables to a list of constraints affecting the given variables.
(type=dict)

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