def test_inconsistent_active_spaces(mol_name, act_electrons, act_orbitals,
message_match):
r"""Test that an error is raised if an inconsistent active space is generated"""
molecule = MolecularData(filename=os.path.join(ref_dir, mol_name))
with pytest.raises(ValueError, match=message_match):
qchem.active_space(
molecule.n_electrons,
molecule.n_orbitals,
mult=molecule.multiplicity,
active_electrons=act_electrons,
active_orbitals=act_orbitals,
)
def test_active_spaces(mol_name, n_act_electrons, n_act_orbitals,
docc_indices_ref, act_indices_ref):
r"""Test the correctness of the generated active spaces"""
docc_indices, active_indices = qchem.active_space(mol_name, ref_dir,
n_act_electrons,
n_act_orbitals)
assert docc_indices == docc_indices_ref
assert active_indices == act_indices_ref
def test_active_spaces(mol_name, act_electrons, act_orbitals, core_ref,
active_ref):
r"""Test the correctness of the generated active spaces"""
molecule = MolecularData(filename=os.path.join(ref_dir, mol_name))
core, active = qchem.active_space(
molecule.n_electrons,
molecule.n_orbitals,
mult=molecule.multiplicity,
active_electrons=act_electrons,
active_orbitals=act_orbitals,
)
assert core == core_ref
assert active == active_ref
# :width: 50%
# :align: center
#
# .. note::
# The number of *active spin-orbitals* determines the *number of qubits* required
# to perform quantum simulations of the electronic structure of the molecule.
#
# For the case of the water molecule described using a minimal basis set, we have a total of ten
# electrons occupying the first five out of seven molecular orbitals in the HF reference state.
# Let's partition the HF orbitals to define an active space of four electrons in four active
# orbitals:
electrons = 10
orbitals = 7
core, active = qchem.active_space(electrons,
orbitals,
active_electrons=4,
active_orbitals=4)
##############################################################################
# Viewing the results:
print("List of core orbitals: {:}".format(core))
print("List of active orbitals: {:}".format(active))
print("Number of qubits required for quantum simulation: {:}".format(
2 * len(active)))
##############################################################################
# Notice that calling the :func:`~.pennylane_qchem.qchem.active_space` function without
# specifying an active space results in no core orbitals---*all* molecular orbitals are
# considered to be active.
def test_inconsistent_active_spaces(mol_name, n_act_electrons, n_act_orbitals,
message_match):
r"""Test that an error is raised if an inconsistent active space is generated"""
with pytest.raises(ValueError, match=message_match):
qchem.active_space(mol_name, ref_dir, n_act_electrons, n_act_orbitals)