Roll back the default on unitary to np.complex64, change default for final_state_vector (#5636)

Rolls back change in #5426 that set the default precision on `Circuit#unitary` to `np.complex128`.

Also sets the default on `Circuit#final_state_vector` to `np.complex128`.  There was a deprecation warning that this was going to be downgraded to `np.complex64`,, but this will now remain `np.complex128`.  This is breaking in that is someone explicitly passed `dtype=None` to this method it would now break.  

Rolls back #5426 #5616 #5537 #5535

Author: dabacon

cirq-core/cirq/circuits/circuit.py

@@ -1003,7 +1003,7 @@ def unitary(
         qubit_order: 'cirq.QubitOrderOrList' = ops.QubitOrder.DEFAULT,
         qubits_that_should_be_present: Iterable['cirq.Qid'] = (),
         ignore_terminal_measurements: bool = True,
-        dtype: Type[np.complexfloating] = np.complex64,
+        dtype: Type[np.complexfloating] = np.complex128,
     ) -> np.ndarray:
         """Converts the circuit into a unitary matrix, if possible.
 
@@ -1018,10 +1018,11 @@ def unitary(
             ignore_terminal_measurements: When set, measurements at the end of
                 the circuit are ignored instead of causing the method to
                 fail.
-            dtype: The numpy dtype for the returned unitary. `dtype` must be
-                a complex np.dtype, unless all operations in the circuit have
-                unitary matrices with exclusively real coefficients
-                (e.g. an H + TOFFOLI circuit).
+            dtype: The numpy dtype for the returned unitary. Defaults to
+                np.complex128. Specifying np.complex64 will run faster at the
+                cost of precision. `dtype` must be a complex np.dtype, unless
+                all operations in the circuit have unitary matrices with
+                exclusively real coefficients (e.g. an H + TOFFOLI circuit).
 
         Returns:
             A (possibly gigantic) 2d numpy array corresponding to a matrix
@@ -1093,7 +1094,7 @@ def final_state_vector(
         qubit_order: 'cirq.QubitOrderOrList' = ops.QubitOrder.DEFAULT,
         qubits_that_should_be_present: Iterable['cirq.Qid'] = (),
         ignore_terminal_measurements: Optional[bool] = None,
-        dtype: Optional[Type[np.complexfloating]] = None,
+        dtype: Type[np.complexfloating] = np.complex128,
         param_resolver: 'cirq.ParamResolverOrSimilarType' = None,
         seed: 'cirq.RANDOM_STATE_OR_SEED_LIKE' = None,
     ) -> np.ndarray:
@@ -1143,14 +1144,6 @@ def final_state_vector(
                 )
             ignore_terminal_measurements = True
 
-        if dtype is None:
-            _compat._warn_or_error(
-                '`dtype` will default to np.complex64 in v0.16. '
-                'To use the previous default, please explicitly include '
-                '`dtype=np.complex128` when calling this method.'
-            )
-            dtype = np.complex128
-
         from cirq.sim.mux import final_state_vector
 
         program = Circuit(cirq.I(q) for q in qubits_that_should_be_present) + self

cirq-core/cirq/circuits/circuit_test.py

@@ -2957,62 +2957,6 @@ def test_final_state_vector(circuit_cls):
         )
 
 
-@pytest.mark.parametrize('circuit_cls', [cirq.Circuit, cirq.FrozenCircuit])
-def test_final_state_vector_deprecated_params(circuit_cls):
-    a = cirq.NamedQubit('a')
-    b = cirq.NamedQubit('b')
-    # Extra qubits.
-    cirq.testing.assert_allclose_up_to_global_phase(
-        circuit_cls().final_state_vector(ignore_terminal_measurements=False, dtype=np.complex128),
-        np.array([1]),
-        atol=1e-8,
-    )
-    with cirq.testing.assert_deprecated("Inject identity operators", deadline="v0.16"):
-        cirq.testing.assert_allclose_up_to_global_phase(
-            circuit_cls().final_state_vector(
-                qubits_that_should_be_present=[a],
-                ignore_terminal_measurements=False,
-                dtype=np.complex128,
-            ),
-            np.array([1, 0]),
-            atol=1e-8,
-        )
-    with cirq.testing.assert_deprecated("Inject identity operators", deadline="v0.16"):
-        cirq.testing.assert_allclose_up_to_global_phase(
-            circuit_cls(cirq.X(b)).final_state_vector(
-                qubits_that_should_be_present=[a],
-                ignore_terminal_measurements=False,
-                dtype=np.complex128,
-            ),
-            np.array([0, 1, 0, 0]),
-            atol=1e-8,
-        )
-
-    with cirq.testing.assert_deprecated("To drop terminal measurements", deadline="v0.16"):
-        cirq.testing.assert_allclose_up_to_global_phase(
-            circuit_cls(cirq.X(a), cirq.measure(a)).final_state_vector(dtype=np.complex128),
-            np.array([0, 1]),
-            atol=1e-8,
-        )
-
-    with cirq.testing.assert_deprecated("`dtype` will default to np.complex64", deadline="v0.16"):
-        cirq.testing.assert_allclose_up_to_global_phase(
-            circuit_cls(cirq.X(a)).final_state_vector(ignore_terminal_measurements=False),
-            np.array([0, 1]),
-            atol=1e-8,
-        )
-
-    # Non-keyword args.
-    with cirq.testing.assert_deprecated("Only use keyword arguments", deadline="v0.16"):
-        cirq.testing.assert_allclose_up_to_global_phase(
-            circuit_cls(cirq.X(a) ** 0.5).final_state_vector(
-                1, ignore_terminal_measurements=False, dtype=np.complex128
-            ),
-            np.array([1, 1j]) * np.sqrt(0.5),
-            atol=1e-8,
-        )
-
-
 @pytest.mark.parametrize('circuit_cls', [cirq.Circuit, cirq.FrozenCircuit])
 @pytest.mark.parametrize('resolve_fn', [cirq.resolve_parameters, cirq.resolve_parameters_once])
 def test_is_parameterized(circuit_cls, resolve_fn):

cirq-core/cirq/contrib/acquaintance/executor_test.py

@@ -119,9 +119,7 @@ def test_executor_random(
     circuit.append(cca.LinearPermutationGate(num_qubits, permutation)(*qubits))
     actual_unitary = circuit.unitary()
 
-    np.testing.assert_allclose(
-        actual=actual_unitary, desired=expected_unitary, verbose=True, atol=1e-6
-    )
+    np.testing.assert_allclose(actual=actual_unitary, desired=expected_unitary, verbose=True)
 
 
 def test_acquaintance_operation():

cirq-core/cirq/contrib/paulistring/clifford_optimize_test.py

@@ -121,4 +121,4 @@ def test_optimize_large_circuit():
 
     c_opt = clifford_optimized_circuit(c_orig)
 
-    cirq.testing.assert_allclose_up_to_global_phase(c_orig.unitary(), c_opt.unitary(), atol=1e-6)
+    cirq.testing.assert_allclose_up_to_global_phase(c_orig.unitary(), c_opt.unitary(), atol=1e-7)

cirq-core/cirq/contrib/paulistring/optimize_test.py

@@ -48,17 +48,17 @@ def test_optimize():
 
     c_opt = optimized_circuit(c_orig)
 
-    cirq.testing.assert_allclose_up_to_global_phase(c_orig.unitary(), c_opt.unitary(), atol=1e-6)
+    cirq.testing.assert_allclose_up_to_global_phase(c_orig.unitary(), c_opt.unitary(), atol=1e-7)
 
     # TODO(#5546) Fix '[Z]^1' (should be 'Z')
     cirq.testing.assert_has_diagram(
         c_opt,
         """
-0: ───X^0.5────────────@──────────────────────────────────────────────
+0: ───X^0.5────────────@────────────────────────────────────────
                        │
-1: ───@───────X^-0.5───@───@────────────────@───Z^-0.5────────────────
+1: ───@───────X^-0.5───@───@────────────────@───Z^-0.5──────────
       │                    │                │
-2: ───@────────────────────@───[X]^(-7/8)───@───[X]^-0.25───[Z]^(1)───
+2: ───@────────────────────@───[X]^(-7/8)───@───[X]^-0.25───Z───
 """,
     )
 
@@ -69,7 +69,7 @@ def test_optimize_large_circuit():
 
     c_opt = optimized_circuit(c_orig)
 
-    cirq.testing.assert_allclose_up_to_global_phase(c_orig.unitary(), c_opt.unitary(), atol=1e-6)
+    cirq.testing.assert_allclose_up_to_global_phase(c_orig.unitary(), c_opt.unitary(), atol=1e-7)
 
     assert (
         sum(
@@ -87,7 +87,7 @@ def test_repeat_limit():
 
     c_opt = optimized_circuit(c_orig, repeat=1)
 
-    cirq.testing.assert_allclose_up_to_global_phase(c_orig.unitary(), c_opt.unitary(), atol=1e-6)
+    cirq.testing.assert_allclose_up_to_global_phase(c_orig.unitary(), c_opt.unitary(), atol=1e-7)
 
     assert (
         sum(

cirq-core/cirq/contrib/paulistring/pauli_string_dag_test.py

@@ -26,5 +26,5 @@ def test_pauli_string_dag_from_circuit():
     c_left_reordered = c_left_dag.to_circuit()
 
     cirq.testing.assert_allclose_up_to_global_phase(
-        c_left.unitary(), c_left_reordered.unitary(), atol=1e-6
+        c_left.unitary(), c_left_reordered.unitary(), atol=1e-7
     )

cirq-core/cirq/contrib/paulistring/pauli_string_optimize_test.py

@@ -37,7 +37,7 @@ def test_optimize():
     c_opt = pauli_string_optimized_circuit(c_orig)
 
     cirq.testing.assert_allclose_up_to_global_phase(
-        c_orig.unitary(), c_expected.unitary(), atol=1e-6
+        c_orig.unitary(), c_expected.unitary(), atol=1e-7
     )
 
     cirq.testing.assert_has_diagram(
@@ -81,4 +81,4 @@ def test_optimize_large_circuit():
 
     c_opt = pauli_string_optimized_circuit(c_orig)
 
-    cirq.testing.assert_allclose_up_to_global_phase(c_orig.unitary(), c_opt.unitary(), atol=1e-6)
+    cirq.testing.assert_allclose_up_to_global_phase(c_orig.unitary(), c_opt.unitary(), atol=1e-7)

cirq-core/cirq/contrib/paulistring/separate_test.py

@@ -23,7 +23,7 @@ def test_toffoli_separate():
     c_left, c_right = convert_and_separate_circuit(circuit)
 
     cirq.testing.assert_allclose_up_to_global_phase(
-        circuit.unitary(), (c_left + c_right).unitary(), atol=1e-6
+        circuit.unitary(), (c_left + c_right).unitary(), atol=1e-7
     )
 
     assert all(isinstance(op, cirq.PauliStringPhasor) for op in c_left.all_operations())

cirq-core/cirq/contrib/qasm_import/qasm_test.py

@@ -51,6 +51,6 @@ def test_consistency_with_qasm_output_and_qiskit():
     circuit2 = circuit_from_qasm(qasm)
 
     cirq_unitary = cirq.unitary(circuit2)
-    ct.assert_allclose_up_to_global_phase(cirq_unitary, cirq.unitary(circuit1), atol=1e-6)
+    ct.assert_allclose_up_to_global_phase(cirq_unitary, cirq.unitary(circuit1), atol=1e-8)
 
     cq.assert_qiskit_parsed_qasm_consistent_with_unitary(qasm, cirq_unitary)

cirq-core/cirq/ion/convert_to_ion_gates_test.py

@@ -88,7 +88,7 @@ def test_convert_to_ion_gates():
         atol=1e-4,
     )
     assert cirq.allclose_up_to_global_phase(
-        cirq.unitary(cirq.Circuit(rcnot)), cirq.unitary(OtherCNOT().on(q0, q1)), atol=1e-6
+        cirq.unitary(cirq.Circuit(rcnot)), cirq.unitary(OtherCNOT().on(q0, q1)), atol=1e-7
     )