add idle gate

qutip · May 9, 2021 · d58c310 · d58c310
1 parent a41a148
commit d58c310
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Showing 3 changed files with 20 additions and 4 deletions.
diff --git a/src/qutip_qip/circuit.py b/src/qutip_qip/circuit.py
@@ -49,7 +49,7 @@
                                         iswap, sqrtswap, sqrtiswap, fredkin,
                                         toffoli, controlled_gate, globalphase,
                                         expand_operator, gate_sequence_product)
-from qutip import tensor, basis, identity, ket2dm
+from qutip import tensor, basis, identity, ket2dm, qeye
 from qutip.qobj import Qobj
 from qutip.measurement import measurement_statistics
 
@@ -750,7 +750,7 @@ def _resolve_to_universal(self, gate, temp_resolved, basis_1q, basis_2q):
 
     def _gate_IGNORED(self, gate, temp_resolved):
         temp_resolved.append(gate)
-    _gate_RY = _gate_RZ = _gate_basis_2q = _gate_IGNORED
+    _gate_RY = _gate_RZ = _gate_basis_2q = _gate_IDLE = _gate_IGNORED
     _gate_CNOT = _gate_RX = _gate_IGNORED
 
     def _gate_SQRTNOT(self, gate, temp_resolved):
@@ -1258,7 +1258,7 @@ def resolve_gates(self, basis=["CNOT", "RX", "RY", "RZ"]):
                                num_cbits=self.num_cbits)
         temp_resolved = []
 
-        basis_1q_valid = ["RX", "RY", "RZ"]
+        basis_1q_valid = ["RX", "RY", "RZ", "IDLE"]
         basis_2q_valid = ["CNOT", "CSIGN", "ISWAP", "SQRTSWAP", "SQRTISWAP"]
 
         num_measurements = len(list(filter(
@@ -1277,6 +1277,7 @@ def resolve_gates(self, basis=["CNOT", "RX", "RY", "RZ"]):
                 elif gate in basis_1q_valid:
                     basis_1q.append(gate)
                 else:
+                    pass
                     raise NotImplementedError(
                         "%s is not a valid basis gate" % gate)
             if len(basis_1q) == 1:
@@ -1550,6 +1551,8 @@ def propagators(self, expand=True):
                                            gate.targets[0]))
             elif gate.name == "GLOBALPHASE":
                 self.U_list.append(globalphase(gate.arg_value, self.N))
+            elif gate.name == "IDLE":
+                self.U_list.append(qeye(self.N * [2]))
             elif gate.name in self.user_gates:
                 if gate.controls is not None:
                     raise ValueError("A user defined gate {} takes only  "
@@ -1655,6 +1658,8 @@ def propagators_no_expand(self):
                 self.U_list.append(toffoli())
             elif gate.name == "GLOBALPHASE":
                 self.U_list.append(globalphase(gate.arg_value, n))
+            elif gate.name == "IDLE":
+                self.U_list.append(qeye(2))
             elif gate.name in self.user_gates:
                 if gate.controls is not None:
                     raise ValueError("A user defined gate {} takes only  "

diff --git a/src/qutip_qip/compiler/gatecompiler.py b/src/qutip_qip/compiler/gatecompiler.py
@@ -75,7 +75,10 @@ def __init__(self, num_qubits=None, params=None, pulse_dict=None, N=None):
         self.num_qubits = num_qubits or N
         self.N = num_qubits  # backward compatibility
         self.params = params if params is not None else {}
-        self.gate_compiler = {"GLOBALPHASE": self.globalphase_compiler}
+        self.gate_compiler = {
+            "GLOBALPHASE": self.globalphase_compiler,
+            "IDLE": self.idle_compiler
+        }
         self.args = {}
         self.args.update({"params": self.params})
         self.global_phase = 0.
@@ -98,6 +101,13 @@ def globalphase_compiler(self, gate, args):
         """
         pass
 
+    def idle_compiler(self, gate, args):
+        """
+        Compiler for the GLOBALPHASE gate
+        """
+        idle_time = gate.arg_value
+        return [Instruction(gate, idle_time, [])]
+
     def compile(
             self, circuit, schedule_mode=None, args=None):
         """

diff --git a/tests/test_device.py b/tests/test_device.py
@@ -172,6 +172,7 @@ def test_numerical_evolution(
 circuit.add_gate("ISWAP", targets=[2, 1])
 circuit.add_gate("Y", targets=[2])
 circuit.add_gate("Z", targets=[0])
+circuit.add_gate("IDLE", targets=[1], arg_value=1.)
 circuit.add_gate("CNOT", targets=[0], controls=[2])
 circuit.add_gate("Z", targets=[1])
 circuit.add_gate("X", targets=[1])