def test_excited_state_particle_nonconserving(self):
"""Test getting an excited state of a Hamiltonian that conserves
particle number."""
for n_qubits in self.n_qubits_range:
# Initialize a non-particle-number-conserving Hamiltonian
quadratic_hamiltonian = random_quadratic_hamiltonian(
n_qubits, False)
# Pick some orbitals to occupy
num_occupied_orbitals = numpy.random.randint(1, n_qubits + 1)
occupied_orbitals = numpy.random.choice(range(n_qubits),
num_occupied_orbitals,
False)
# Compute the Gaussian state
circuit_energy, gaussian_state = jw_get_gaussian_state(
quadratic_hamiltonian, occupied_orbitals)
# Compute the true energy
orbital_energies, constant = (
quadratic_hamiltonian.orbital_energies())
energy = numpy.sum(orbital_energies[occupied_orbitals]) + constant
# Check that the energies match
self.assertAlmostEqual(energy, circuit_energy)
# Check that the state obtained using the circuit is an eigenstate
# with the correct eigenvalue
sparse_operator = get_sparse_operator(quadratic_hamiltonian)
difference = (sparse_operator * gaussian_state -
energy * gaussian_state)
discrepancy = numpy.amax(numpy.abs(difference))
self.assertAlmostEqual(discrepancy, 0)
def test_ground_state_particle_nonconserving(self):
"""Test getting the ground state of a Hamiltonian that does not
conserve particle number."""
for n_qubits in self.n_qubits_range:
# Initialize a non-particle-number-conserving Hamiltonian
quadratic_hamiltonian = random_quadratic_hamiltonian(
n_qubits, False)
# Compute the true ground state
sparse_operator = get_sparse_operator(quadratic_hamiltonian)
ground_energy, _ = get_ground_state(sparse_operator)
# Compute the ground state using the circuit
circuit_energy, circuit_state = (
jw_get_gaussian_state(quadratic_hamiltonian))
# Check that the energies match
self.assertAlmostEqual(ground_energy, circuit_energy)
# Check that the state obtained using the circuit is a ground state
difference = (sparse_operator * circuit_state -
ground_energy * circuit_state)
discrepancy = numpy.amax(numpy.abs(difference))
self.assertAlmostEqual(discrepancy, 0)
def test_bad_input(self):
"""Test bad input."""
with self.assertRaises(ValueError):
jw_get_gaussian_state('a')