dwavebinarycsp.factories.constraint.gates.halfadder_gate#

halfadder_gate(variables, vartype=Vartype.BINARY, name='HALF_ADDER')[source]#

Half adder.

Parameters:

  • variables (list) – Variable labels for the and gate as [in1, in2, sum, carry], where in1, in2 are inputs to be added and sum and ‘carry’ the resultant outputs.

  • vartype (Vartype, optional, default='BINARY') –

    Variable type. Accepted input values:

    • Vartype.SPIN, ‘SPIN’, {-1, 1}

    • Vartype.BINARY, ‘BINARY’, {0, 1}

  • name (str, optional, default='HALF_ADDER') – Name for the constraint.

Returns:

Constraint that is satisfied when its variables are assigned values that match the valid states of a Boolean half adder.

Return type:

Constraint(Constraint)

Examples

>>> import dwavebinarycsp.factories.constraint.gates as gates
>>> csp = dwavebinarycsp.ConstraintSatisfactionProblem(dwavebinarycsp.BINARY)
>>> csp.add_constraint(gates.halfadder_gate(['a', 'b', 'total', 'carry'], name='HA1'))
>>> csp.check({'a': 1, 'b': 1, 'total': 0, 'carry': 1})
True