Fix some mypy --next numpy typing errors

[pavoljuhas]

• Fix return value type error for measure_density_matrix()
• Replace type spec Type[np.number] --> np.typing.DTypeLike

[MichaelBroughton]

Nice!

[CirqBot]

Automerge cancelled: A status check is failing.

[vtomole]

Another flake cc @dabacon

E         =================================== FAILURES ===================================
E         _ test_decompose_two_qubit_interaction_into_four_fsim_gates_equivalence[obj113-fsim_gate113] _
E         
E         obj = cirq.ISWAP
E         fsim_gate = cirq.FSimGate(theta=1.511761740437375, phi=0.00019081760422245964)
E         
E             @pytest.mark.parametrize('obj,fsim_gate', itertools.product(UNITARY_OBJS, FEASIBLE_FSIM_GATES))
E             def test_decompose_two_qubit_interaction_into_four_fsim_gates_equivalence(
E                 obj: Any, fsim_gate: cirq.FSimGate
E             ):
E                 qubits = obj.qubits if isinstance(obj, cirq.Operation) else cirq.LineQubit.range(2)
E                 circuit = cirq.decompose_two_qubit_interaction_into_four_fsim_gates(obj, fsim_gate=fsim_gate)
E                 desired_unitary = obj if isinstance(obj, np.ndarray) else cirq.unitary(obj)
E                 for operation in circuit.all_operations():
E                     assert len(operation.qubits) < 2 or operation.gate == fsim_gate
E                 assert len(circuit) <= 4 * 3 + 5
E         >       assert cirq.approx_eq(circuit.unitary(qubit_order=qubits), desired_unitary, atol=2e-4)
E         E       assert False
E         E        +  where False = <function approx_eq at 0x7f859b580c10>(array([[ 9.9999988e-01+5.0663948e-07j,  3.3753872e-07+1.5762454e-07j,  3.5567297e-07-2.1532583e-07j,  5.9372034e-08+5....0e-08j, -3.0437056e-07-2.2733417e-07j,  3.0149198e-07-3.0524998e-07j,  9.9999994e-01-5.6624413e-07j]], dtype=complex64), array([[1.+0.j, 0.+0.j, 0.+0.j, 0.+0.j],\n       [0.+0.j, 0.+0.j, 0.+1.j, 0.+0.j],\n       [0.+0.j, 0.+1.j, 0.+0.j, 0.+0.j],\n       [0.+0.j, 0.+0.j, 0.+0.j, 1.+0.j]]), atol=0.0002)
E         E        +    where <function approx_eq at 0x7f859b580c10> = cirq.approx_eq
E         E        +    and   array([[ 9.9999988e-01+5.0663948e-07j,  3.3753872e-07+1.5762454e-07j,  3.5567297e-07-2.1532583e-07j,  5.9372034e-08+5....0e-08j, -3.0437056e-07-2.2733417e-07j,  3.0149198e-07-3.0524998e-07j,  9.9999994e-01-5.6624413e-07j]], dtype=complex64) = <bound method AbstractCircuit.unitary of cirq.Circuit([\n    cirq.Moment(\n        cirq.MatrixGate(np.array([[(-0.640690...746901229944e-17j), (0.9060735868811878-0.4231201426973904j)]], dtype=np.complex128)).on(cirq.LineQubit(1)),\n    ),\n])>(qubit_order=[cirq.LineQubit(0), cirq.LineQubit(1)])
E         E        +      where <bound method AbstractCircuit.unitary of cirq.Circuit([\n    cirq.Moment(\n        cirq.MatrixGate(np.array([[(-0.640690...746901229944e-17j), (0.9060735868811878-0.4231201426973904j)]], dtype=np.complex128)).on(cirq.LineQubit(1)),\n    ),\n])> = cirq.Circuit([\n    cirq.Moment(\n        cirq.MatrixGate(np.array([[(-0.6406907775377064+0.2991911221579444j), (0.64069...7746901229944e-17j), (0.9060735868811878-0.4231201426973904j)]], dtype=np.complex128)).on(cirq.LineQubit(1)),\n    ),\n]).unitary
E         
E         cirq-core/cirq/transformers/analytical_decompositions/two_qubit_to_fsim_test.py:120: AssertionError
E         _ test_decompose_two_qubit_interaction_into_four_fsim_gates_equivalence[obj132-fsim_gate132] _
E         
E         obj = cirq.SWAP
E         fsim_gate = cirq.FSimGate(theta=1.511761740437375, phi=0.00019081760422245964)
E         
E             @pytest.mark.parametrize('obj,fsim_gate', itertools.product(UNITARY_OBJS, FEASIBLE_FSIM_GATES))
E             def test_decompose_two_qubit_interaction_into_four_fsim_gates_equivalence(
E                 obj: Any, fsim_gate: cirq.FSimGate
E             ):
E                 qubits = obj.qubits if isinstance(obj, cirq.Operation) else cirq.LineQubit.range(2)
E                 circuit = cirq.decompose_two_qubit_interaction_into_four_fsim_gates(obj, fsim_gate=fsim_gate)
E                 desired_unitary = obj if isinstance(obj, np.ndarray) else cirq.unitary(obj)
E                 for operation in circuit.all_operations():
E                     assert len(operation.qubits) < 2 or operation.gate == fsim_gate
E                 assert len(circuit) <= 4 * 3 + 5
E         >       assert cirq.approx_eq(circuit.unitary(qubit_order=qubits), desired_unitary, atol=2e-4)
E         E       assert False
E         E        +  where False = <function approx_eq at 0x7f859b580c10>(array([[ 9.9999988e-01-7.45058060e-08j,  2.4655461e-04-1.01402402e-04j,  4.1902065e-05-1.02013350e-04j, -6.7055225e-08...08j,  2.4649501e-04+1.01476908e-04j,  4.2043626e-05+1.02020800e-04j,  9.9999964e-01-8.94069672e-08j]], dtype=complex64), array([[1.+0.j, 0.+0.j, 0.+0.j, 0.+0.j],\n       [0.+0.j, 0.+0.j, 1.+0.j, 0.+0.j],\n       [0.+0.j, 1.+0.j, 0.+0.j, 0.+0.j],\n       [0.+0.j, 0.+0.j, 0.+0.j, 1.+0.j]]), atol=0.0002)
E         E        +    where <function approx_eq at 0x7f859b580c10> = cirq.approx_eq
E         E        +    and   array([[ 9.9999988e-01-7.45058060e-08j,  2.4655461e-04-1.01402402e-04j,  4.1902065e-05-1.02013350e-04j, -6.7055225e-08...08j,  2.4649501e-04+1.01476908e-04j,  4.2043626e-05+1.02020800e-04j,  9.9999964e-01-8.94069672e-08j]], dtype=complex64) = <bound method AbstractCircuit.unitary of cirq.Circuit([\n    cirq.Moment(\n        cirq.MatrixGate(np.array([[(-1.012275...4999999992842133j), (0.5000000007157869+0.5000000007157869j)]], dtype=np.complex128)).on(cirq.LineQubit(1)),\n    ),\n])>(qubit_order=[cirq.LineQubit(0), cirq.LineQubit(1)])
E         E        +      where <bound method AbstractCircuit.unitary of cirq.Circuit([\n    cirq.Moment(\n        cirq.MatrixGate(np.array([[(-1.012275...4999999992842133j), (0.5000000007157869+0.5000000007157869j)]], dtype=np.complex128)).on(cirq.LineQubit(1)),\n    ),\n])> = cirq.Circuit([\n    cirq.Moment(\n        cirq.MatrixGate(np.array([[(-1.0122753614557024e-09-0.7071067811865476j), (0.7....4999999992842133j), (0.5000000007157869+0.5000000007157869j)]], dtype=np.complex128)).on(cirq.LineQubit(1)),\n    ),\n]).unitary
E         
E         cirq-core/cirq/transformers/analytical_decompositions/two_qubit_to_fsim_test.py:120: AssertionError

Re-running.