def test_apply_individual_nbody_error(self):
fop = FermionOperator('1^ 0')
fop += FermionOperator('2^ 0')
fop += FermionOperator('2^ 1')
hamil = sparse_hamiltonian.SparseHamiltonian(fop)
wfn = Wavefunction([[2, 0, 2]], broken=['spin'])
self.assertRaises(ValueError, wfn._apply_individual_nbody, hamil)
self.assertRaises(ValueError, wfn._evolve_individual_nbody, 0.1, hamil)
fop = FermionOperator('1^ 0')
fop += FermionOperator('2^ 0')
hamil = sparse_hamiltonian.SparseHamiltonian(fop)
self.assertRaises(ValueError, wfn._evolve_individual_nbody, 0.1, hamil)
fop = FermionOperator('1^ 0', 1.0)
fop += FermionOperator('0^ 1', 0.9)
hamil = sparse_hamiltonian.SparseHamiltonian(fop)
self.assertRaises(ValueError, wfn._evolve_individual_nbody, 0.1, hamil)
fop = FermionOperator('1^ 0^')
hamil = sparse_hamiltonian.SparseHamiltonian(fop)
self.assertRaises(ValueError, wfn._apply_individual_nbody, hamil)
self.assertRaises(ValueError, wfn._evolve_individual_nbody, 0.1, hamil)
self.assertRaises(TypeError, wfn._evolve_individual_nbody, 0.1, 1)
def test_sparse():
"""Test some of the functions in SparseHamiltonian."""
oper = FermionOperator('0 0^')
oper += FermionOperator('1 1^')
test = sparse_hamiltonian.SparseHamiltonian(oper)
assert test.rank() == 2
test = sparse_hamiltonian.SparseHamiltonian(oper, False)
assert not test.is_individual()
def test_apply_nbody(self):
wfn = Wavefunction([[2, 0, 2]])
wfn.set_wfn(strategy='random')
fac = 3.14
fop = FermionOperator('1^ 1', fac)
hamil = sparse_hamiltonian.SparseHamiltonian(fop)
out1 = wfn._apply_few_nbody(hamil)
fop = FermionOperator('1 1^', fac)
hamil = sparse_hamiltonian.SparseHamiltonian(fop)
out2 = wfn._apply_few_nbody(hamil)
out2.scale(-1.0)
out2.ax_plus_y(fac, wfn)
self.assertTrue((out1 - out2).norm() < 1.0e-8)
def rdm(
self,
string: str,
brawfn: Optional['Wavefunction'] = None
) -> Union[complex, numpy.ndarray]:
""" Returns rank-1 RDM. The operator order is specified by string.
Note that, if the entire RDM is requested for N-broken wave function,
this returns a packed format.
Args:
string (str) - character strings that specify the quantity to be computed
brawfn (Wavefunction) - bra-side wave function for transition RDM (optional)
Returns:
Resulting RDM in numpy.ndarray or element in complex
"""
rank = len(string.split()) // 2
if any(char.isdigit() for char in string):
result = self.apply(sparse_hamiltonian.SparseHamiltonian(string))
if brawfn is None:
return vdot(self, result)
return vdot(brawfn, result)
fqe_ops_utils.validate_rdm_string(string)
rdm = list(self._compute_rdm(rank, brawfn))
return wick(string, rdm, self._conserve_spin)
def expectationValue(
self,
ops: Union['fqe_operator.FqeOperator', 'hamiltonian.Hamiltonian'],
brawfn: 'Wavefunction' = None) -> Union[complex, numpy.ndarray]:
"""Calculates expectation values given operators
Args:
ops (FqeOperator or Hamiltonian) - operator for which the expectation value is \
computed
brawfn (Wavefunction) - bra-side wave function for transition quantity (optional)
Returns:
(complex or numpy.ndarray) - resulting expectation value or RDM
"""
if isinstance(ops, fqe_operator.FqeOperator):
if brawfn:
return ops.contract(brawfn, self)
return ops.contract(self, self)
if isinstance(ops, str):
if any(char.isdigit() for char in ops):
ops = sparse_hamiltonian.SparseHamiltonian(ops)
else:
return self.rdm(ops, brawfn=brawfn)
if not isinstance(ops, hamiltonian.Hamiltonian):
raise TypeError('Expected an Fqe Hamiltonian or Operator' \
' but recieved {}'.format(type(ops)))
workwfn = self.apply(ops)
if brawfn:
return vdot(brawfn, workwfn)
return vdot(self, workwfn)
def get_sparse_hamiltonian(operators: Union['FermionOperator', str],
conserve_spin: bool = True,
e_0: complex = 0. + 0.j
) -> 'sparse_hamiltonian.SparseHamiltonian':
"""Initialize the sparse hamiltonaian
Args:
operators (Union[FermionOperator, str]) - the FermionOperator to be used to \
initialize the sparse Hamiltonian
conserve_spin (bool) - whether the Hamiltonian conserves Sz
e_0 (complex) - scalar part of the Hamiltonian
"""
return sparse_hamiltonian.SparseHamiltonian(operators,
conserve_spin=conserve_spin,
e_0=e_0)
def build_hamiltonian(ops: Union[FermionOperator, hamiltonian.Hamiltonian],
norb: int = 0,
conserve_number: bool = True,
e_0: complex = 0. + 0.j) -> 'hamiltonian.Hamiltonian':
"""Build a Hamiltonian object for the fqe
Args:
ops (FermionOperator, hamiltonian.Hamiltonian) - input operator as \
FermionOperator. If a Hamiltonian is passed as an argument, \
this function returns as is.
norb (int) - the number of orbitals in the system
conserve_number (bool) - whether the operator conserves the number
e_0 (complex) - the scalar part of the operator
Returns:
(hamiltonian.Hamiltonian) - General Hamiltonian that is created from ops
"""
if isinstance(ops, hamiltonian.Hamiltonian):
return ops
if isinstance(ops, tuple):
validate_tuple(ops)
return general_hamiltonian.General(ops, e_0=e_0)
if not isinstance(ops, FermionOperator):
raise TypeError('Expected FermionOperator' \
' but received {}.'.format(type(ops)))
assert is_hermitian(ops)
out: Any
if len(ops.terms) <= 2:
out = sparse_hamiltonian.SparseHamiltonian(ops, e_0=e_0)
else:
if not conserve_number:
ops = transform_to_spin_broken(ops)
ops = normal_ordered(ops)
ops_rank, e_0 = split_openfermion_tensor(ops) # type: ignore
if norb == 0:
for term in ops_rank.values():
ablk, bblk = largest_operator_index(term)
norb = max(norb, ablk // 2 + 1, bblk // 2 + 1)
else:
norb = norb
ops_mat = {}
maxrank = 0
for rank, term in ops_rank.items():
index = rank // 2 - 1
ops_mat[index] = fermionops_tomatrix(term, norb)
maxrank = max(index, maxrank)
if len(ops_mat) == 1 and (0 in ops_mat):
out = process_rank2_matrix(ops_mat[0], norb=norb, e_0=e_0)
elif len(ops_mat) == 1 and \
(1 in ops_mat) and \
check_diagonal_coulomb(ops_mat[1]):
out = diagonal_coulomb.DiagonalCoulomb(ops_mat[1], e_0=e_0)
else:
dtypes = [xx.dtype for xx in ops_mat.values()]
dtypes = numpy.unique(dtypes)
if len(dtypes) != 1:
raise TypeError(
"Non-unique coefficient types for input operator")
for i in range(maxrank + 1):
if i not in ops_mat:
mat_dim = tuple([2 * norb for _ in range((i + 1) * 2)])
ops_mat[i] = numpy.zeros(mat_dim, dtype=dtypes[0])
ops_mat2 = []
for i in range(maxrank + 1):
ops_mat2.append(ops_mat[i])
out = general_hamiltonian.General(tuple(ops_mat2), e_0=e_0)
out._conserve_number = conserve_number
return out