def sample_poly(self, poly, fixed_variables=None, **parameters):
"""Sample from the provided binary quadratic model.
Args:
poly (:obj:`dimod.BinaryPolynomial`):
Binary polynomial model to be sampled from.
fixed_variables (dict):
A dictionary of variable assignments.
**parameters:
Parameters for the sampling method, specified by the child sampler.
Returns:
:obj:`dimod.SampleSet`
"""
child = self.child
if fixed_variables is None:
sampleset = child.sample_poly(poly, **parameters)
return sampleset
else:
poly_copy = fix_variables(poly, fixed_variables)
sampleset = child.sample_poly(poly_copy, **parameters)
if len(sampleset):
return append_variables(sampleset, fixed_variables)
elif fixed_variables:
return type(sampleset).from_samples_bqm(fixed_variables,
bqm=poly)
else:
return sampleset
def _hook(sampleset):
# make RoofDualityComposite non-blocking
if sampleset.variables:
if len(sampleset):
return append_variables(sampleset, fixed_variables)
else:
return sampleset.from_samples_bqm((np.empty((0, len(bqm))),
bqm.variables), bqm=bqm)
# there are only fixed variables, make sure that the correct number
# of samples are returned
samples = [fixed_variables]*max(len(sampleset), 1)
return sampleset.from_samples_bqm(samples, bqm=bqm)
def sample(self, bqm, *, components=None, **parameters):
"""Sample from the provided binary quadratic model.
Args:
bqm (:class:`dimod.BinaryQuadraticModel`):
Binary quadratic model to be sampled from.
components (list(set)):
A list of disjoint set of variables that fully partition the variables
**parameters:
Parameters for the sampling method, specified by the child sampler.
Returns:
:class:`dimod.SampleSet`
"""
# make sure the BQM is shapeable
bqm = as_bqm(bqm, cls=[AdjVectorBQM, AdjDictBQM])
# solve the problem on the child system
child = self.child
variables = bqm.variables
if components is None:
components = list(connected_components(bqm))
if isinstance(components, set):
components = [components]
sampleset = None
fixed_value = min(bqm.vartype.value)
for component in components:
bqm_copy = bqm.copy()
bqm_copy.fix_variables(
{i: fixed_value
for i in (variables - component)})
if sampleset is None:
# here .truncate(1) is used to pick the best solution only. The other options
# for future development is to combine all sample with all.
# This way you'd get the same behaviour as the ExactSolver
sampleset = child.sample(bqm_copy, **parameters).truncate(1)
else:
sampleset = append_variables(
sampleset.truncate(1),
child.sample(bqm_copy, **parameters).truncate(1))
if sampleset is None:
return SampleSet.from_samples_bqm({}, bqm)
else:
return SampleSet.from_samples_bqm(sampleset, bqm)