property BinaryQuadraticModel.binary: BinaryQuadraticModel[source]

Binary-valued version of the binary quadratic model.

If the binary quadratic model is binary-valued, this references itself, otherwise it references a view.


This example uses a binary-valued Boolean XOR gate, dimod.generators.xor_gate(), to ensure that an unbiased eleven-spin ferromagnetic chain, which has two best solutions of all-up and all-down spins, selects the all-down solution by requiring that \(s_5 = s_0 \oplus s_10\) (the only assignment that produces a ferromagnetic chain is \(-1 = -1 \oplus -1\)).

>>> import dimod
>>> import numpy as np
>>> s = dimod.SpinArray(range(11))
>>> bqm = - dimod.quicksum(s[1:11] * s[0:10])   # ferromagnetic chain
>>> bqm_xor = dimod.generators.xor_gate(0, 10, 5, "aux")
>>> bqm.spin.update(bqm_xor)   # xor left & right spins to middle spin
>>> bqm.vartype is dimod.Vartype.SPIN
>>> sampleset = dimod.drop_variables(dimod.ExactSolver().sample(bqm), "aux")
>>> set(sampleset.first.sample.values()) == {-1}