Rename iswap rotation (#2526)

cirq/__init__.py

@@ -239,6 +239,7 @@
     QubitOrderOrList,
     reset,
     ResetChannel,
+    riswap,
     Rx,
     Ry,
     Rz,

cirq/ops/__init__.py

@@ -201,6 +201,7 @@
     ISWAP,
     ISwapPowGate,
     ISwapRotation,
+    riswap,
     SWAP,
     SwapPowGate,
 )

cirq/ops/swap_gates.py

@@ -26,7 +26,7 @@
 import sympy
 
 from cirq import protocols, value
-from cirq._compat import proper_repr
+from cirq._compat import deprecated, proper_repr
 from cirq._doc import document
 from cirq.ops import common_gates, gate_features, eigen_gate, raw_types
 
@@ -248,10 +248,15 @@ def __repr__(self):
                                              self._global_shift)
 
 
-def ISwapRotation(angle_rads: value.TParamVal) -> ISwapPowGate:
+def riswap(rads: value.TParamVal) -> ISwapPowGate:
     """Returns gate with matrix exp(+i angle_rads (X⊗X + Y⊗Y) / 2)."""
-    pi = sympy.pi if protocols.is_parameterized(angle_rads) else np.pi
-    return ISwapPowGate()**(2 * angle_rads / pi)
+    pi = sympy.pi if protocols.is_parameterized(rads) else np.pi
+    return ISwapPowGate()**(2 * rads / pi)
+
+
+@deprecated(deadline='v0.8.0', fix='Use cirq.riswap, instead.')
+def ISwapRotation(angle_rads: value.TParamVal) -> ISwapPowGate:
+    return riswap(angle_rads)
 
 
 SWAP = SwapPowGate()

cirq/ops/swap_gates_test.py

@@ -145,8 +145,8 @@ def test_trace_distance_over_range_of_exponents():
 
 
 @pytest.mark.parametrize('angle_rads', (-np.pi, -np.pi / 3, -0.1, np.pi / 5))
-def test_iswap_rotation_unitary(angle_rads):
-    actual = cirq.unitary(cirq.ISwapRotation(angle_rads))
+def test_riswap_unitary(angle_rads):
+    actual = cirq.unitary(cirq.riswap(angle_rads))
     c = np.cos(angle_rads)
     s = 1j * np.sin(angle_rads)
     # yapf: disable
@@ -159,8 +159,8 @@ def test_iswap_rotation_unitary(angle_rads):
 
 
 @pytest.mark.parametrize('angle_rads', (-2 * np.pi / 3, -0.2, 0.4, np.pi / 4))
-def test_iswap_rotation_hamiltonian(angle_rads):
-    actual = cirq.unitary(cirq.ISwapRotation(angle_rads))
+def test_riswap_hamiltonian(angle_rads):
+    actual = cirq.unitary(cirq.riswap(angle_rads))
     x = np.array([[0, 1], [1, 0]])
     y = np.array([[0, -1j], [1j, 0]])
     xx = np.kron(x, x)
@@ -170,6 +170,13 @@ def test_iswap_rotation_hamiltonian(angle_rads):
 
 
 @pytest.mark.parametrize('angle_rads', (-np.pi / 5, 0.4, 2, np.pi))
-def test_iswap_rotation_has_consistent_protocols(angle_rads):
+def test_riswap_has_consistent_protocols(angle_rads):
     cirq.testing.assert_implements_consistent_protocols(
-        cirq.ISwapRotation(angle_rads), ignoring_global_phase=False)
+        cirq.riswap(angle_rads), ignoring_global_phase=False)
+
+
+@pytest.mark.parametrize('angle_rads', (-1, -0.3, 0.2, 1))
+def test_deprecated_riswap(angle_rads):
+    assert np.all(
+        cirq.unitary(cirq.ISwapRotation(angle_rads)) == cirq.unitary(
+            cirq.riswap(angle_rads)))

docs/api.rst

@@ -66,6 +66,7 @@ Unitary effects that can be applied to one or more qubits.
     cirq.SWAP
     cirq.TOFFOLI
     cirq.identity_each
+    cirq.riswap
     cirq.CCXPowGate
     cirq.CCZPowGate
     cirq.CNotPowGate