Mid-circuit measurement POC

Author: ElePT

qiskit/qpy/binary_io/circuits.py

@@ -476,6 +476,7 @@ def _read_instruction(
         circuit._append(inst_obj, qargs, cargs)
         return None
     elif gate_name in custom_operations:
+        print("GATE NAME IN CUSTOM: ", gate_name)
         inst_obj = _parse_custom_operation(
             custom_operations,
             gate_name,
@@ -505,6 +506,7 @@ def _read_instruction(
     else:
         raise AttributeError(f"Invalid instruction type: {gate_name}")
 
+    print(">>>QPY GATE CLASS", gate_class)
     if instruction.label_size <= 0:
         label = None
     if gate_name in ("IfElseOp", "WhileLoopOp"):

qiskit/visualization/circuit/circuit_visualization.py

@@ -429,6 +429,7 @@ def _text_circuit_drawer(
         idle_wires=idle_wires,
         wire_order=wire_order,
     )
+    print("TEXT DRAWING?")
     text_drawing = _text.TextDrawing(
         qubits,
         clbits,

qiskit/visualization/circuit/text.py

@@ -222,17 +222,20 @@ class MeasureFrom(BoxOnQuWire):
         bot: └╥┘    └╥┘
     """
 
-    def __init__(self):
-        super().__init__()
+    def __init__(self, label=""):
+        super().__init__(label)
         self.top_format = self.mid_format = self.bot_format = "%s"
+        if self.label == "measure":
+            mid_content = "M"
+        else:
+            mid_content = self.label
         self.top_connect = "┌─┐"
-        self.mid_content = "┤M├"
+        self.mid_content = "┤" + mid_content + "├"
         self.bot_connect = "└╥┘"
 
         self.top_pad = self.bot_pad = " "
         self._mid_padding = "─"
 
-
 class MultiBox(DrawElement):
     """Elements that are drawn over multiple wires."""
 
@@ -1135,9 +1138,11 @@ def add_connected_gate(node, gates, layer, current_cons, gate_wire_map):
                 if isinstance(modifier, ControlModifier):
                     mod_control = modifier
                     break
-
+        
+        print("OP", isinstance(op, Measure), op)
         if isinstance(op, Measure):
-            gate = MeasureFrom()
+            print("MEASURE?")
+            gate = MeasureFrom(label=op.name)
             layer.set_qubit(node.qargs[0], gate)
             register, _, reg_index = get_bit_reg_index(self._circuit, node.cargs[0])
             if self.cregbundle and register is not None:

test_midcircuit_2.py

@@ -0,0 +1,66 @@
+import io
+
+from qiskit import QuantumCircuit
+from qiskit.circuit import Instruction, Measure
+from qiskit.circuit.singleton import SingletonInstruction, stdlib_singleton_key
+from qiskit.circuit.exceptions import CircuitError
+from qiskit._accelerate.circuit import StandardInstructionType
+from qiskit.qpy import dump, load
+from qiskit.transpiler.passes import ResetAfterMeasureSimplification
+
+
+class CustomMeasurement(Measure):
+    """A custom specialized measurement."""
+
+    def __init__(self, label=None):
+        super().__init__(label=label)
+        if label:
+            self.name= label
+        else:
+            self.name="measure_2"
+
+def create():
+    circ = QuantumCircuit(2, 2)
+    circ.append(CustomMeasurement(), [0], [0])
+    circ.append(CustomMeasurement("measure_3"), [0], [1])
+    circ.measure_all()
+    print(circ.draw())
+    print(circ.data)
+    print("Is subclass", issubclass(CustomMeasurement, Measure))
+    print("Is instance", isinstance(circ.data[0].operation, Measure))
+    return circ
+
+def qpy_roundtrip(circ):
+    print("QPY ROUNDTRIP")
+    with io.BytesIO() as f:
+        dump(circ, f)
+        f.seek(0)
+        out_circ = load(f)[0]
+    print(out_circ.draw())
+    print(out_circ.data)
+    return out_circ
+
+def test_roundtrip(circ, out_circ):
+    print("ARE THEY EQUAL?")
+    for i, out_item in enumerate(out_circ.data):
+        print(out_item.name, "==", circ.data[i].name, "?", out_item == circ.data[i])
+        # if not out_item == circ.data[i]:
+        print("Before: ",isinstance(circ.data[i].operation, Measure), type(circ.data[i].operation).__mro__)
+        print(circ.data[i].operation.definition)
+        print("After: ", isinstance(out_item.operation, Measure), type(out_item.operation).__mro__)
+        print(out_item.operation.definition)
+
+
+def qasm3_roundtrip(circ):
+    import qiskit.qasm3 as qasm3
+    print("QASM3 ROUNDTRIP")
+    qasm_str = qasm3.dumps(circ)
+    circ_qasm = qasm3.loads(qasm_str)
+    return circ_qasm
+
+
+qc = create()
+qpy_qc = qpy_roundtrip(qc)
+test_roundtrip(qc, qpy_qc)
+qasm3_qc = qasm3_roundtrip(qc)
+test_roundtrip(qc, qasm3_qc)