Add the Missing Gates for Conversion (#449)

* add more gates

* fix tests?

* get more info?

* fix integration tests

* fix missing coverage

* add `changelog`

* add test

CHANGELOG.md

@@ -21,6 +21,10 @@
   a ``QuantumCircuit`` using `load`.
   [(#417)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/417)
 
+* Added conversion support for more Qiskit gates to native PennyLane operations -
+  ``Barrier``, ``CYGate``, ``CHGate``, ``CPhase``, ``CCZGate``, ``ECRGate``, and ``GlobalPhaseGate``.
+  [(#449)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/449)
+
 ### Breaking changes 💔
 
 ### Deprecations 👋

pennylane_qiskit/converter.py

@@ -36,7 +36,12 @@
 
 inv_map = {v.__name__: k for k, v in QISKIT_OPERATION_MAP.items()}
 
-dagger_map = {"SdgGate": qml.S, "TdgGate": qml.T, "SXdgGate": qml.SX}
+dagger_map = {
+    "SdgGate": qml.S,
+    "TdgGate": qml.T,
+    "SXdgGate": qml.SX,
+    "GlobalPhaseGate": qml.GlobalPhase,
+}
 
 referral_to_forum = (
     "\n \nIf you are experiencing any difficulties with converting circuits from Qiskit, you can reach out "
@@ -434,6 +439,7 @@ def _function(*args, params: dict = None, wires: list = None, **kwargs):
 
             if instruction_name in dagger_map:
                 operation_class = qml.adjoint(dagger_map[instruction_name])
+                operation_args.extend(operation_params)
 
             elif instruction_name in inv_map:
                 operation_class = getattr(pennylane_ops, inv_map[instruction_name])

pennylane_qiskit/qiskit_device.py

@@ -74,6 +74,13 @@
     "Adjoint(S)": lib.SdgGate,
     "Adjoint(T)": lib.TdgGate,
     "Adjoint(SX)": lib.SXdgGate,
+    "CY": lib.CYGate,
+    "CH": lib.CHGate,
+    "CPhase": lib.CPhaseGate,
+    "CCZ": lib.CCZGate,
+    "ECR": lib.ECRGate,
+    "Barrier": lib.Barrier,
+    "Adjoint(GlobalPhase)": lib.GlobalPhaseGate,
 }
 
 
@@ -351,7 +358,12 @@ def apply_operations(self, operations):
                 # Qiskit such that it matches the PennyLane ordering
                 qregs = list(reversed(qregs))
 
+            if operation in ("Barrier",):
+                # Need to add the num_qubits for instantiating Barrier in Qiskit
+                par = [len(self._reg)]
+
             dag = circuit_to_dag(QuantumCircuit(self._reg, self._creg, name=""))
+
             gate = mapped_operation(*par)
 
             dag.apply_operation_back(gate, qargs=qregs)

tests/test_converter.py

@@ -654,6 +654,7 @@ def test_operations_adjoint_ops(self, recorder):
         qc.sdg([0])
         qc.tdg([0])
         qc.sxdg([0])
+        qc.append(lib.GlobalPhaseGate(1.2))
 
         quantum_circuit = load(qc)
         with recorder:
@@ -671,21 +672,67 @@ def test_operations_adjoint_ops(self, recorder):
         assert len(recorder.queue[2].parameters) == 0
         assert recorder.queue[2].wires == Wires([0])
 
+        assert recorder.queue[3].name == "Adjoint(GlobalPhase)"
+        assert recorder.queue[3].parameters == [1.2]
+        assert recorder.queue[3].wires == Wires([])
+
+    def test_controlled_gates(self, recorder):
+        """Tests loading a circuit with controlled gates."""
+
+        qc = QuantumCircuit(3)
+        qc.cy(0, 1)
+        qc.ch(1, 2)
+        qc.cp(1.2, 2, 1)
+        qc.ccz(0, 2, 1)
+        qc.barrier()
+        qc.ecr(1, 0)
+
+        quantum_circuit = load(qc)
+
+        with recorder:
+            quantum_circuit()
+
+        assert len(recorder.queue) == 6
+
+        assert recorder.queue[0].name == "CY"
+        assert len(recorder.queue[0].parameters) == 0
+        assert recorder.queue[0].wires == Wires([0, 1])
+
+        assert recorder.queue[1].name == "CH"
+        assert len(recorder.queue[1].parameters) == 0
+        assert recorder.queue[1].wires == Wires([1, 2])
+
+        assert recorder.queue[2].name == "ControlledPhaseShift"
+        assert recorder.queue[2].parameters == [1.2]
+        assert recorder.queue[2].wires == Wires([2, 1])
+
+        assert recorder.queue[3].name == "CCZ"
+        assert len(recorder.queue[3].parameters) == 0
+        assert recorder.queue[3].wires == Wires([0, 2, 1])
+
+        assert recorder.queue[4].name == "Barrier"
+        assert len(recorder.queue[4].parameters) == 0
+        assert recorder.queue[4].wires == Wires([0, 1, 2])
+
+        assert recorder.queue[5].name == "ECR"
+        assert len(recorder.queue[5].parameters) == 0
+        assert recorder.queue[5].wires == Wires([1, 0])
+
     def test_operation_transformed_into_qubit_unitary(self, recorder):
         """Tests loading a circuit with operations that can be converted,
         but not natively supported by PennyLane."""
 
         qc = QuantumCircuit(3, 1)
 
-        qc.ch([0], [1])
+        qc.cs([0], [1])
 
         quantum_circuit = load(qc)
         with recorder:
             quantum_circuit()
 
         assert recorder.queue[0].name == "QubitUnitary"
         assert len(recorder.queue[0].parameters) == 1
-        assert np.array_equal(recorder.queue[0].parameters[0], lib.CHGate().to_matrix())
+        assert np.array_equal(recorder.queue[0].parameters[0], lib.CSGate().to_matrix())
         assert recorder.queue[0].wires == Wires([0, 1])
 
 
@@ -1017,7 +1064,7 @@ def test_qasm_from_file(self, tmpdir, recorder):
         with recorder:
             quantum_circuit()
 
-        assert len(recorder.queue) == 10
+        assert len(recorder.queue) == 11
 
         assert recorder.queue[0].name == "PauliX"
         assert recorder.queue[0].parameters == []
@@ -1027,21 +1074,25 @@ def test_qasm_from_file(self, tmpdir, recorder):
         assert recorder.queue[1].parameters == []
         assert recorder.queue[1].wires == Wires([2])
 
-        assert recorder.queue[2].name == "Hadamard"
+        assert recorder.queue[2].name == "Barrier"
         assert recorder.queue[2].parameters == []
-        assert recorder.queue[2].wires == Wires([0])
+        assert recorder.queue[2].wires == Wires([0, 1, 2, 3])
 
         assert recorder.queue[3].name == "Hadamard"
         assert recorder.queue[3].parameters == []
-        assert recorder.queue[3].wires == Wires([1])
+        assert recorder.queue[3].wires == Wires([0])
 
         assert recorder.queue[4].name == "Hadamard"
         assert recorder.queue[4].parameters == []
-        assert recorder.queue[4].wires == Wires([2])
+        assert recorder.queue[4].wires == Wires([1])
 
         assert recorder.queue[5].name == "Hadamard"
         assert recorder.queue[5].parameters == []
-        assert recorder.queue[5].wires == Wires([3])
+        assert recorder.queue[5].wires == Wires([2])
+
+        assert recorder.queue[6].name == "Hadamard"
+        assert recorder.queue[6].parameters == []
+        assert recorder.queue[6].wires == Wires([3])
 
     def test_qasm_file_not_found_error(self):
         """Tests that an error is propagated, when a non-existing file is specified for parsing."""
@@ -1449,7 +1500,7 @@ def ansatz_false():
 
             qml.RZ(0.24, wires=0)
             qml.CNOT([0, 1])
-
+            qml.Barrier([0, 1, 2])
             return [qml.expval(m) for m in [m0, m1, qml.measure(0), qml.measure(1), qml.measure(2)]]
 
         assert loaded_qiskit_circuit() == built_pl_circuit()

tests/test_qiskit_device.py

@@ -183,3 +183,16 @@ def test_num_executions_recorded(self, device):
         tapes = [self.tape1, self.tape2]
         res = dev.batch_execute(tapes)
         assert dev.num_executions == 1
+
+    def test_barrier_tape(self, device, tol):
+        """Tests that the barriers are accounted for during conversion."""
+        dev = device(2)
+
+        @qml.qnode(dev)
+        def barrier_func():
+            qml.Barrier([0, 1])
+            return qml.state()
+
+        res = barrier_func()
+        assert barrier_func.tape.operations[0] == qml.Barrier([0, 1])
+        assert np.allclose(res, dev.batch_execute([barrier_func.tape]), atol=0)