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Fix state vector shape validation in PauliSum #8465

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Fix state vector shape validation in PauliSum #8465

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6 changes: 3 additions & 3 deletions cirq-core/cirq/ops/linear_combinations.py
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Original file line number Diff line number Diff line change
Expand Up @@ -698,14 +698,14 @@ def expectation_from_state_vector(

size = state_vector.size
num_qubits = size.bit_length() - 1
_validate_qubit_mapping(qubit_map, self.qubits, num_qubits)

if len(state_vector.shape) != 1 and state_vector.shape != (2,) * num_qubits:
if state_vector.shape not in ((2**num_qubits,), (2,) * num_qubits):
raise ValueError(
"Input array does not represent a state vector "
"with shape `(2 ** n,)` or `(2, ..., 2)`."
)

_validate_qubit_mapping(qubit_map, self.qubits, num_qubits)

if check_preconditions:
qis.validate_normalized_state_vector(
state_vector=state_vector,
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11 changes: 8 additions & 3 deletions cirq-core/cirq/ops/linear_combinations_test.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1307,7 +1307,7 @@ def test_expectation_from_state_vector_invalid_input() -> None:
q0, q1, q2, q3 = cirq.LineQubit.range(4)
psum = cirq.X(q0) + 2 * cirq.Y(q1) + 3 * cirq.Z(q3)
q_map = {q0: 0, q1: 1, q3: 2}
wf: np.ndarray = np.array([1, 0, 0, 0, 0, 0, 0], dtype=np.complex64)
wf: np.ndarray = np.array([1, 0, 0, 0, 0, 0, 0, 0], dtype=np.complex64)

im_psum = (1j + 1) * psum
with pytest.raises(NotImplementedError, match='non-Hermitian'):
Expand All @@ -1333,8 +1333,13 @@ def test_expectation_from_state_vector_invalid_input() -> None:
with pytest.raises(ValueError, match='indices'):
psum.expectation_from_state_vector(wf, {q0: 0, q1: 0, q3: 2})

with pytest.raises(ValueError, match='9'):
psum.expectation_from_state_vector(np.arange(9, dtype=np.complex64), q_map)
for bad_size in (3, 5, 7, 9):
with pytest.raises(ValueError, match='shape'):
psum.expectation_from_state_vector(np.zeros(bad_size, dtype=np.complex64), q_map)
with pytest.raises(ValueError, match='shape'):
psum.expectation_from_state_vector(
np.zeros(bad_size, dtype=np.complex64), q_map, check_preconditions=False
)
q_map_2 = {q0: 0, q1: 1, q2: 2, q3: 3}
with pytest.raises(ValueError, match='normalized'):
psum.expectation_from_state_vector(np.arange(16, dtype=np.complex64), q_map_2)
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2 changes: 1 addition & 1 deletion cirq-core/cirq/ops/pauli_string.py
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Original file line number Diff line number Diff line change
Expand Up @@ -606,7 +606,7 @@ def expectation_from_state_vector(

size = state_vector.size
num_qubits = size.bit_length() - 1
if len(state_vector.shape) != 1 and state_vector.shape != (2,) * num_qubits:
if state_vector.shape not in ((2**num_qubits,), (2,) * num_qubits):
raise ValueError(
"Input array does not represent a state vector "
"with shape `(2 ** n,)` or `(2, ..., 2)`."
Expand Down
9 changes: 7 additions & 2 deletions cirq-core/cirq/ops/pauli_string_test.py
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Original file line number Diff line number Diff line change
Expand Up @@ -964,8 +964,13 @@ def test_expectation_from_state_vector_invalid_input() -> None:
_ = ps.expectation_from_state_vector(wf, {q0: 0, q1: 1, q2: 0})

# Incorrectly shaped state_vector input.
with pytest.raises(ValueError, match='7'):
ps.expectation_from_state_vector(np.arange(7, dtype=np.complex64), q_map)
for bad_size in (3, 5, 7):
with pytest.raises(ValueError, match='shape'):
ps.expectation_from_state_vector(np.zeros(bad_size, dtype=np.complex64), q_map)
with pytest.raises(ValueError, match='shape'):
ps.expectation_from_state_vector(
np.zeros(bad_size, dtype=np.complex64), q_map, check_preconditions=False
)
q_map_2 = {q0: 0, q1: 1, q2: 2, q3: 3}
with pytest.raises(ValueError, match='normalized'):
ps.expectation_from_state_vector(np.arange(16, dtype=np.complex64), q_map_2)
Expand Down
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