def test_identity_recognized_as_potential_term(self):
potential_terms, kinetic_terms = (
diagonal_coulomb_potential_and_kinetic_terms_as_arrays(
FermionOperator.identity()))
self.assertListEqual(list(potential_terms),
[FermionOperator.identity()])
self.assertListEqual(list(kinetic_terms), [])
def test_diagonal_coulomb_hamiltonian_class(self):
hamiltonian = DiagonalCoulombHamiltonian(
numpy.array([[1, 1], [1, 1]], dtype=float),
numpy.array([[0, 1], [1, 0]], dtype=float),
constant=2.3)
potential_terms, kinetic_terms = (
diagonal_coulomb_potential_and_kinetic_terms_as_arrays(
hamiltonian))
potential = sum(potential_terms, FermionOperator.zero())
kinetic = sum(kinetic_terms, FermionOperator.zero())
expected_potential = (2.3 * FermionOperator.identity() +
FermionOperator('0^ 0') +
FermionOperator('1^ 1') -
FermionOperator('1^ 0^ 1 0', 2.0))
expected_kinetic = FermionOperator('0^ 1') + FermionOperator('1^ 0')
self.assertEqual(potential, expected_potential)
self.assertEqual(kinetic, expected_kinetic)
def test_split_operator_error_operator_VT_order_against_definition(self):
hamiltonian = (normal_ordered(fermi_hubbard(3, 3, 1., 4.0)) -
2.3 * FermionOperator.identity())
potential_terms, kinetic_terms = (
diagonal_coulomb_potential_and_kinetic_terms_as_arrays(
hamiltonian))
potential = sum(potential_terms, FermionOperator.zero())
kinetic = sum(kinetic_terms, FermionOperator.zero())
error_operator = (
split_operator_trotter_error_operator_diagonal_two_body(
hamiltonian, order='V+T'))
# V-then-T ordered double commutators: [V, [T, V]] + [T, [T, V]] / 2
inner_commutator = normal_ordered(commutator(kinetic, potential))
error_operator_definition = normal_ordered(
commutator(potential, inner_commutator))
error_operator_definition += normal_ordered(
commutator(kinetic, inner_commutator)) / 2.0
error_operator_definition /= 12.0
self.assertEqual(error_operator, error_operator_definition)
def construct_exact_ham(orbprop, orb_qubit_map=None):
ham = FermionOperator.identity() * orbprop.hcore
ham += construct_ham_1body(orbprop.hint, orb_qubit_map)
ham += construct_ham_2body(orbprop.gint, orb_qubit_map)
return ham
