def test_minimization_problem(self):
"""Tests the optimizer with a minimization problem"""
optimizer = GoemansWilliamsonOptimizer(num_cuts=10, seed=0)
problem = Maxcut(self.graph).to_quadratic_program()
# artificially convert to minimization
max2min = MaximizeToMinimize()
problem = max2min.convert(problem)
results = optimizer.solve(problem)
np.testing.assert_almost_equal([0, 1, 1, 0], results.x, 3)
np.testing.assert_almost_equal(4, results.fval, 3)
def test_converter_list(self):
"""Test converter list"""
op = QuadraticProgram()
op.integer_var(0, 3, "x")
op.binary_var("y")
op.maximize(linear={"x": 1, "y": 2})
op.linear_constraint(linear={
"x": 1,
"y": 1
},
sense="LE",
rhs=3,
name="xy_leq")
min_eigen_solver = NumPyMinimumEigensolver()
# a single converter
qp2qubo = QuadraticProgramToQubo()
min_eigen_optimizer = MinimumEigenOptimizer(min_eigen_solver,
converters=qp2qubo)
result = min_eigen_optimizer.solve(op)
self.assertEqual(result.fval, 4)
# a list of converters
ineq2eq = InequalityToEquality()
int2bin = IntegerToBinary()
penalize = LinearEqualityToPenalty()
max2min = MaximizeToMinimize()
converters = [ineq2eq, int2bin, penalize, max2min]
min_eigen_optimizer = MinimumEigenOptimizer(min_eigen_solver,
converters=converters)
result = min_eigen_optimizer.solve(op)
self.assertEqual(result.fval, 4)
with self.assertRaises(TypeError):
invalid = [qp2qubo, "invalid converter"]
MinimumEigenOptimizer(min_eigen_solver, converters=invalid)
def test_maximize_to_minimize(self):
"""Test maximization to minimization conversion"""
op_max = QuadraticProgram()
op_min = QuadraticProgram()
for i in range(2):
op_max.binary_var(name="x{}".format(i))
op_min.binary_var(name="x{}".format(i))
op_max.integer_var(name="x{}".format(2), lowerbound=-3, upperbound=3)
op_min.integer_var(name="x{}".format(2), lowerbound=-3, upperbound=3)
op_max.maximize(constant=3,
linear={"x0": 1},
quadratic={("x1", "x2"): 2})
op_min.minimize(constant=3,
linear={"x0": 1},
quadratic={("x1", "x2"): 2})
# check conversion of maximization problem
conv = MaximizeToMinimize()
op_conv = conv.convert(op_max)
self.assertEqual(op_conv.objective.sense,
op_conv.objective.Sense.MINIMIZE)
x = [0, 1, 2]
fval_min = op_conv.objective.evaluate(conv.interpret(x))
self.assertAlmostEqual(fval_min, -7)
self.assertAlmostEqual(op_max.objective.evaluate(x), -fval_min)
# check conversion of minimization problem
op_conv = conv.convert(op_min)
self.assertEqual(op_conv.objective.sense, op_min.objective.sense)
fval_min = op_conv.objective.evaluate(conv.interpret(x))
self.assertAlmostEqual(op_min.objective.evaluate(x), fval_min)
def test_empty_problem(self):
"""Test empty problem"""
op = QuadraticProgram()
conv = InequalityToEquality()
op = conv.convert(op)
conv = IntegerToBinary()
op = conv.convert(op)
conv = LinearEqualityToPenalty()
op = conv.convert(op)
conv = MaximizeToMinimize()
op = conv.convert(op)
_, shift = op.to_ising()
self.assertEqual(shift, 0.0)
def test_converter_list(self):
"""Test converters list"""
# Input.
model = Model()
x_0 = model.binary_var(name="x0")
x_1 = model.binary_var(name="x1")
model.maximize(-x_0 + 2 * x_1)
op = QuadraticProgram()
op.from_docplex(model)
# Get the optimum key and value.
# a single converter.
qp2qubo = QuadraticProgramToQubo()
gmf = GroverOptimizer(
4,
num_iterations=self.n_iter,
quantum_instance=self.sv_simulator,
converters=qp2qubo,
)
results = gmf.solve(op)
self.validate_results(op, results)
# a list of converters
ineq2eq = InequalityToEquality()
int2bin = IntegerToBinary()
penalize = LinearEqualityToPenalty()
max2min = MaximizeToMinimize()
converters = [ineq2eq, int2bin, penalize, max2min]
gmf = GroverOptimizer(
4,
num_iterations=self.n_iter,
quantum_instance=self.sv_simulator,
converters=converters,
)
results = gmf.solve(op)
self.validate_results(op, results)
# invalid converters
with self.assertRaises(TypeError):
invalid = [qp2qubo, "invalid converter"]
GroverOptimizer(
4,
num_iterations=self.n_iter,
quantum_instance=self.sv_simulator,
converters=invalid,
)
