enable partially entangling ms gates

pennylane_ionq/device.py

@@ -85,6 +85,7 @@ class IonQDevice(QubitDevice):
             distribution has peaks. See `IonQ Debiasing and Sharpening
             <https://ionq.com/resources/debiasing-and-sharpening>`_ for details.
     """
+
     # pylint: disable=too-many-instance-attributes
     name = "IonQ PennyLane plugin"
     short_name = "ionq"
@@ -114,7 +115,9 @@ def __init__(
         sharpen=False,
     ):
         if shots is None:
-            raise ValueError("The ionq device does not support analytic expectation values.")
+            raise ValueError(
+                "The ionq device does not support analytic expectation values."
+            )
 
         super().__init__(wires=wires, shots=shots)
         self.target = target
@@ -164,7 +167,9 @@ def apply(self, operations, **kwargs):
         rotations = kwargs.pop("rotations", [])
 
         if len(operations) == 0 and len(rotations) == 0:
-            warnings.warn("Circuit is empty. Empty circuits return failures. Submitting anyway.")
+            warnings.warn(
+                "Circuit is empty. Empty circuits return failures. Submitting anyway."
+            )
 
         for i, operation in enumerate(operations):
             if i > 0 and operation.name in {
@@ -201,7 +206,9 @@ def _apply_operation(self, operation):
 
         if self.gateset == "native":
             if len(par) > 1:
-                gate["phases"] = [float(v) for v in par]
+                gate["phases"] = [float(v) for v in par[:2]]
+                if len(par) > 2:
+                    gate["rotation"] = float(par[2])
             else:
                 gate["phase"] = float(par[0])
         elif par:
@@ -246,7 +253,8 @@ def prob(self):
             # Here, we rearrange the states to match the big-endian ordering
             # expected by PennyLane.
             basis_states = (
-                int(bin(int(k))[2:].rjust(self.num_wires, "0")[::-1], 2) for k in self.histogram
+                int(bin(int(k))[2:].rjust(self.num_wires, "0")[::-1], 2)
+                for k in self.histogram
             )
             idx = np.fromiter(basis_states, dtype=int)
 
@@ -266,7 +274,9 @@ def probability(self, wires=None, shot_range=None, bin_size=None):
         if shot_range is None and bin_size is None:
             return self.marginal_prob(self.prob, wires)
 
-        return self.estimate_probability(wires=wires, shot_range=shot_range, bin_size=bin_size)
+        return self.estimate_probability(
+            wires=wires, shot_range=shot_range, bin_size=bin_size
+        )
 
 
 class SimulatorDevice(IonQDevice):
@@ -285,6 +295,7 @@ class SimulatorDevice(IonQDevice):
         api_key (str): The IonQ API key. If not provided, the environment
             variable ``IONQ_API_KEY`` is used.
     """
+
     name = "IonQ Simulator PennyLane plugin"
     short_name = "ionq.simulator"
 
@@ -329,6 +340,7 @@ class QPUDevice(IonQDevice):
             your expected output distribution has peaks. See `IonQ Debiasing and Sharpening
             <https://ionq.com/resources/debiasing-and-sharpening>`_ for details.
     """
+
     name = "IonQ QPU PennyLane plugin"
     short_name = "ionq.qpu"
 

pennylane_ionq/ops.py

@@ -33,6 +33,7 @@ class GPI(Operation):  # pylint: disable=too-few-public-methods
         phi (float): phase :math:`\phi`
         wires (Sequence[int]): the subsystems the operation acts on
     """
+
     num_params = 1
     num_wires = 1
     grad_method = None
@@ -53,33 +54,41 @@ class GPI2(Operation):  # pylint: disable=too-few-public-methods
         phi (float): phase :math:`\phi`
         wires (Sequence[int]): the subsystems the operation acts on
     """
+
     num_params = 1
     num_wires = 1
     grad_method = None
 
 
 class MS(Operation):  # pylint: disable=too-few-public-methods
-    r"""MS(phi0, phi1, wires)
-    2-qubit entanlging MS gate.
+    r"""MS(phi0, phi1, theta=0.25, wires)
+    2-qubit entangling MS gate.
 
     .. math::
 
-       MS(\phi_{0}, \phi_{1}) =
+       MS(\phi_{0}, \phi_{1}, \theta) =
             \frac{1}{\sqrt{2}}\begin{pmatrix}
-                1 & 0 & 0 & -i e^{-2 \pi i(\phi_{0}+\phi_{1})} \\
-                0 & 1 & -i e^{-2 \pi i (\phi_{0}-\phi_{1})} & 0 \\
-                0 & -i e^{2 \pi i(\phi_{0}-\phi_{1})} & 1 & 0 \\
-                -i e^{2 \pi i(\phi_{0}+\phi_{1})} & 0 & 0 & 1
+                \cos(\theta / 2) & 0 & 0 & -i e^{-2 \pi i(\phi_{0}+\phi_{1})} \\
+                0 & \cos(\theta / 2) & -i e^{-2 \pi i (\phi_{0}-\phi_{1})} & 0 \\
+                0 & -i e^{2 \pi i(\phi_{0}-\phi_{1})} & \cos(\theta / 2) & 0 \\
+                -i e^{2 \pi i(\phi_{0}+\phi_{1})} & 0 & 0 & \cos(\theta / 2)
             \end{pmatrix}
+
     Args:
-        phi0 (float): phase of the first qubit :math:`\phi`
-        phi1 (float): phase of the second qubit :math:`\phi`
+        phi0 (float): phase of the first qubit :math:`\phi_0`
+        phi1 (float): phase of the second qubit :math:`\phi_1`
+        theta (float): entanglement ratio of the qubits :math:`\theta` [0, 0.25], defaults to 0.25
         wires (Sequence[int]): the subsystems the operation acts on
     """
-    num_params = 2
+
+    num_params = 3
     num_wires = 2
+    par_domain = "R"
     grad_method = None
 
+    def __init__(self, phi0, phi1, theta=0.25, wires=None):
+        super().__init__(phi0, phi1, theta, wires=wires)
+
 
 # Custom operations for the QIS Gateset below
 
@@ -101,6 +110,7 @@ class XX(Operation):
         phi (float): rotation angle :math:`\phi`
         wires (Sequence[int]): the subsystems the operation acts on
     """
+
     num_params = 1
     num_wires = 2
     grad_method = "A"
@@ -123,6 +133,7 @@ class YY(Operation):
         phi (float): rotation angle :math:`\phi`
         wires (Sequence[int]): the subsystems the operation acts on
     """
+
     num_params = 1
     num_wires = 2
     grad_method = "A"
@@ -145,6 +156,7 @@ class ZZ(Operation):
         phi (float): rotation angle :math:`\phi`
         wires (Sequence[int]): the subsystems the operation acts on
     """
+
     num_params = 1
     num_wires = 2
     grad_method = "A"

tests/test_device.py

@@ -52,11 +52,15 @@ def test_generate_samples_qpu_device(self, wires, histogram):
 
         unique_outcomes1 = np.unique(sample1, axis=0)
         unique_outcomes2 = np.unique(sample2, axis=0)
-        assert np.all(unique_outcomes1 == unique_outcomes2)  # possible outcomes are the same
+        assert np.all(
+            unique_outcomes1 == unique_outcomes2
+        )  # possible outcomes are the same
 
         sorted_outcomes1 = np.sort(sample1, axis=0)
         sorted_outcomes2 = np.sort(sample2, axis=0)
-        assert np.all(sorted_outcomes1 == sorted_outcomes2)  # set of outcomes is the same
+        assert np.all(
+            sorted_outcomes1 == sorted_outcomes2
+        )  # set of outcomes is the same
 
 
 class TestDeviceIntegration:
@@ -96,7 +100,9 @@ def test_failedcircuit(self, monkeypatch):
         monkeypatch.setattr(
             requests, "post", lambda url, timeout, data, headers: (url, data, headers)
         )
-        monkeypatch.setattr(ResourceManager, "handle_response", lambda self, response: None)
+        monkeypatch.setattr(
+            ResourceManager, "handle_response", lambda self, response: None
+        )
         monkeypatch.setattr(Job, "is_complete", False)
         monkeypatch.setattr(Job, "is_failed", True)
 
@@ -111,13 +117,17 @@ def test_shots(self, shots, monkeypatch, mocker, tol):
         monkeypatch.setattr(
             requests, "post", lambda url, timeout, data, headers: (url, data, headers)
         )
-        monkeypatch.setattr(ResourceManager, "handle_response", lambda self, response: None)
+        monkeypatch.setattr(
+            ResourceManager, "handle_response", lambda self, response: None
+        )
         monkeypatch.setattr(Job, "is_complete", True)
 
         def fake_response(self, resource_id=None, params=None):
             """Return fake response data"""
             fake_json = {"0": 1}
-            setattr(self.resource, "data", type("data", tuple(), {"value": fake_json})())
+            setattr(
+                self.resource, "data", type("data", tuple(), {"value": fake_json})()
+            )
 
         monkeypatch.setattr(ResourceManager, "get", fake_response)
 
@@ -133,20 +143,26 @@ def circuit():
         circuit()
         assert json.loads(spy.call_args[1]["data"])["shots"] == shots
 
-    @pytest.mark.parametrize("error_mitigation", [None, {"debias": True}, {"debias": False}])
+    @pytest.mark.parametrize(
+        "error_mitigation", [None, {"debias": True}, {"debias": False}]
+    )
     def test_error_mitigation(self, error_mitigation, monkeypatch, mocker):
         """Test that shots are correctly specified when submitting a job to the API."""
 
         monkeypatch.setattr(
             requests, "post", lambda url, timeout, data, headers: (url, data, headers)
         )
-        monkeypatch.setattr(ResourceManager, "handle_response", lambda self, response: None)
+        monkeypatch.setattr(
+            ResourceManager, "handle_response", lambda self, response: None
+        )
         monkeypatch.setattr(Job, "is_complete", True)
 
         def fake_response(self, resource_id=None, params=None):
             """Return fake response data"""
             fake_json = {"0": 1}
-            setattr(self.resource, "data", type("data", tuple(), {"value": fake_json})())
+            setattr(
+                self.resource, "data", type("data", tuple(), {"value": fake_json})()
+            )
 
         monkeypatch.setattr(ResourceManager, "get", fake_response)
 
@@ -167,7 +183,10 @@ def circuit():
         spy = mocker.spy(requests, "post")
         circuit()
         if error_mitigation is not None:
-            assert json.loads(spy.call_args[1]["data"])["error_mitigation"] == error_mitigation
+            assert (
+                json.loads(spy.call_args[1]["data"])["error_mitigation"]
+                == error_mitigation
+            )
         else:
             with pytest.raises(KeyError, match="error_mitigation"):
                 json.loads(spy.call_args[1]["data"])["error_mitigation"]
@@ -218,12 +237,15 @@ def test_probability(self):
         assert np.array_equal(dev.probability(shot_range=(0, 2)), [0, 0, 0, 1])
 
         uniform_prob = [0.25] * 4
-        with patch("pennylane_ionq.device.SimulatorDevice.prob", new_callable=PropertyMock) as mock_prob:
+        with patch(
+            "pennylane_ionq.device.SimulatorDevice.prob", new_callable=PropertyMock
+        ) as mock_prob:
             mock_prob.return_value = uniform_prob
             assert np.array_equal(dev.probability(), uniform_prob)
 
-
-    @pytest.mark.parametrize("backend", ["harmony", "aria-1", "aria-2", "forte-1", None])
+    @pytest.mark.parametrize(
+        "backend", ["harmony", "aria-1", "aria-2", "forte-1", None]
+    )
     def test_backend_initialization(self, backend):
         """Test that the device initializes with the correct backend."""
         dev = qml.device(
@@ -304,6 +326,7 @@ def mock_submit_job(*args):
             GPI(0.1, wires=[0])
             GPI2(0.2, wires=[1])
             MS(0.2, 0.3, wires=[1, 2])
+            MS(0.4, 0.5, 0.1, wires=[1, 2])
 
         dev.apply(tape.operations)
 
@@ -326,4 +349,11 @@ def mock_submit_job(*args):
             "gate": "ms",
             "targets": [1, 2],
             "phases": [0.2, 0.3],
+            "rotation": 0.25,
+        }
+        assert dev.job["input"]["circuit"][3] == {
+            "gate": "ms",
+            "targets": [1, 2],
+            "phases": [0.4, 0.5],
+            "rotation": 0.1,
         }