Replace QReg by IList[Qubit] (#181)

* Replace QReg by IList[Qubit]

* Size of IList in test

* Raise an InterpreterError instead of RuntimeError in measure impl

Author: david-pl

src/bloqade/pyqrack/__init__.py

@@ -1,7 +1,6 @@
 from .reg import (
     CBitRef as CBitRef,
     CRegister as CRegister,
-    PyQrackReg as PyQrackReg,
     QubitState as QubitState,
     Measurement as Measurement,
     PyQrackQubit as PyQrackQubit,

src/bloqade/pyqrack/noise/native.py

@@ -93,7 +93,7 @@ def atom_loss_channel(
 
         for qarg in active_qubits:
             if interp.rng_state.uniform() <= stmt.prob:
-                qarg.ref.sim_reg.m(qarg.addr)
+                qarg.sim_reg.m(qarg.addr)
                 qarg.drop()
 
         return ()

src/bloqade/pyqrack/qasm2/core.py

@@ -1,9 +1,12 @@
+from typing import Any
+
 from kirin import interp
+from kirin.interp import InterpreterError
+from kirin.dialects import ilist
 
 from bloqade.pyqrack.reg import (
     CBitRef,
     CRegister,
-    PyQrackReg,
     QubitState,
     Measurement,
     PyQrackQubit,
@@ -19,14 +22,13 @@ def qreg_new(
         self, interp: PyQrackInterpreter, frame: interp.Frame, stmt: core.QRegNew
     ):
         n_qubits: int = frame.get(stmt.n_qubits)
-        return (
-            PyQrackReg(
-                size=n_qubits,
-                sim_reg=interp.memory.sim_reg,
-                addrs=interp.memory.allocate(n_qubits),
-                qubit_state=[QubitState.Active] * n_qubits,
-            ),
+        qreg = ilist.IList(
+            [
+                PyQrackQubit(i, interp.memory.sim_reg, QubitState.Active)
+                for i in interp.memory.allocate(n_qubits=n_qubits)
+            ]
         )
+        return (qreg,)
 
     @interp.impl(core.CRegNew)
     def creg_new(
@@ -39,7 +41,9 @@ def creg_new(
     def qreg_get(
         self, interp: PyQrackInterpreter, frame: interp.Frame, stmt: core.QRegGet
     ):
-        return (PyQrackQubit(ref=frame.get(stmt.reg), pos=frame.get(stmt.idx)),)
+        reg = frame.get(stmt.reg)
+        i = frame.get(stmt.idx)
+        return (reg[i],)
 
     @interp.impl(core.CRegGet)
     def creg_get(
@@ -51,28 +55,23 @@ def creg_get(
     def measure(
         self, interp: PyQrackInterpreter, frame: interp.Frame, stmt: core.Measure
     ):
-        qarg: PyQrackQubit | PyQrackReg = frame.get(stmt.qarg)
+        qarg: PyQrackQubit | ilist.IList[PyQrackQubit, Any] = frame.get(stmt.qarg)
         carg: CBitRef | CRegister = frame.get(stmt.carg)
 
         if isinstance(qarg, PyQrackQubit) and isinstance(carg, CBitRef):
             if qarg.is_active():
                 carg.set_value(Measurement(qarg.sim_reg.m(qarg.addr)))
             else:
                 carg.set_value(interp.loss_m_result)
-        elif isinstance(qarg, PyQrackReg) and isinstance(carg, CRegister):
-            # TODO: clean up iteration after PyQrackReg is refactored
-            for i in range(qarg.size):
-                qubit = qarg[i]
-
-                # TODO: make this consistent with PyQrackReg __getitem__ ?
+        elif isinstance(qarg, ilist.IList) and isinstance(carg, CRegister):
+            for i, qubit in enumerate(qarg):
                 cbit = CBitRef(carg, i)
-
                 if qubit.is_active():
-                    cbit.set_value(Measurement(qarg.sim_reg.m(qubit.addr)))
+                    cbit.set_value(Measurement(qubit.sim_reg.m(qubit.addr)))
                 else:
                     cbit.set_value(interp.loss_m_result)
         else:
-            raise RuntimeError(
+            raise InterpreterError(
                 f"Expected measure call on either a single qubit and classical bit, or two registers, but got the types {type(qarg)} and {type(carg)}"
             )
 

src/bloqade/pyqrack/qasm2/glob.py

@@ -3,7 +3,7 @@
 from kirin import interp
 from kirin.dialects import ilist
 
-from bloqade.pyqrack.reg import PyQrackReg
+from bloqade.pyqrack.reg import PyQrackQubit
 from bloqade.pyqrack.base import PyQrackInterpreter
 from bloqade.qasm2.dialects import glob
 
@@ -12,7 +12,9 @@
 class PyQrackMethods(interp.MethodTable):
     @interp.impl(glob.UGate)
     def ugate(self, interp: PyQrackInterpreter, frame: interp.Frame, stmt: glob.UGate):
-        registers: ilist.IList[PyQrackReg, Any] = frame.get(stmt.registers)
+        registers: ilist.IList[ilist.IList[PyQrackQubit, Any], Any] = frame.get(
+            stmt.registers
+        )
         theta, phi, lam = (
             frame.get(stmt.theta),
             frame.get(stmt.phi),

src/bloqade/pyqrack/reg.py

@@ -1,8 +1,8 @@
 import enum
-from typing import TYPE_CHECKING, List
+from typing import TYPE_CHECKING
 from dataclasses import dataclass
 
-from bloqade.qasm2.types import QReg, Qubit
+from bloqade.qasm2.types import Qubit
 
 if TYPE_CHECKING:
     from pyqrack import QrackSimulator
@@ -45,57 +45,18 @@ class QubitState(enum.Enum):
     Lost = enum.auto()
 
 
-@dataclass(frozen=True)
-class PyQrackReg(QReg):  # TODO: clean up implementation with list base class
-    """Simulation runtime value of a quantum register."""
-
-    size: int
-    """The number of qubits in this register."""
-
-    sim_reg: "QrackSimulator"
-    """The register of the simulator."""
-
-    addrs: tuple[int, ...]
-    """The global addresses of the qubits in this register."""
-
-    qubit_state: List[QubitState]
-    """The state of each qubit in this register."""
-
-    def drop(self, pos: int):
-        """Drop the qubit at the given position in-place.
-
-        Args
-            pos (int): The position of the qubit to drop.
-
-        """
-        assert self.qubit_state[pos] is QubitState.Active, "Qubit already lost"
-        self.qubit_state[pos] = QubitState.Lost
-
-    def __getitem__(self, pos: int):
-        if not 0 <= pos < self.size:
-            raise IndexError("Qubit index out of bounds of register.")
-        return PyQrackQubit(self, pos)
-
-
-@dataclass(frozen=True)
+@dataclass
 class PyQrackQubit(Qubit):
     """The runtime representation of a qubit reference."""
 
-    ref: PyQrackReg
-    """The quantum register that is holding this qubit."""
+    addr: int
+    """The address of this qubit in the quantum register."""
 
-    pos: int
-    """The position of this qubit in the quantum register."""
-
-    @property
-    def sim_reg(self):
-        """The register of the simulator."""
-        return self.ref.sim_reg
+    sim_reg: "QrackSimulator"
+    """The register of the simulator."""
 
-    @property
-    def addr(self) -> int:
-        """The global address of the qubit."""
-        return self.ref.addrs[self.pos]
+    state: QubitState
+    """The state of the qubit (active/lost)"""
 
     def is_active(self) -> bool:
         """Check if the qubit is active.
@@ -104,8 +65,8 @@ def is_active(self) -> bool:
             True if the qubit is active, False otherwise.
 
         """
-        return self.ref.qubit_state[self.pos] is QubitState.Active
+        return self.state is QubitState.Active
 
     def drop(self):
         """Drop the qubit in-place."""
-        self.ref.drop(self.pos)
+        self.state = QubitState.Lost

src/bloqade/qasm2/types.py

@@ -1,4 +1,5 @@
 from kirin import types
+from kirin.dialects import ilist
 
 from bloqade.types import Qubit as Qubit, QubitType as QubitType
 
@@ -15,11 +16,7 @@ class Bit:
     pass
 
 
-class QReg:
-    """Runtime representation of a quantum register."""
-
-    def __getitem__(self, index) -> Qubit:
-        raise NotImplementedError("cannot call __getitem__ outside of a kernel")
+QReg = ilist.IList[Qubit, types.Any]
 
 
 class CReg:
@@ -32,7 +29,7 @@ def __getitem__(self, index) -> Bit:
 BitType = types.PyClass(Bit)
 """Kirin type for a classical bit."""
 
-QRegType = types.PyClass(QReg)
+QRegType = ilist.IListType[QubitType, types.Any]
 """Kirin type for a quantum register."""
 
 CRegType = types.PyClass(CReg)

test/pyqrack/runtime/noise/native/test_loss.py

@@ -1,10 +1,12 @@
+from typing import Literal
 from unittest.mock import Mock
 
 from kirin import ir
+from kirin.dialects import ilist
 
 from bloqade import qasm2
 from bloqade.noise import native
-from bloqade.pyqrack import PyQrackInterpreter, reg
+from bloqade.pyqrack import PyQrackQubit, PyQrackInterpreter, reg
 from bloqade.pyqrack.base import MockMemory
 
 simulation = qasm2.extended.add(native)
@@ -34,12 +36,12 @@ def test_atom_loss(c: qasm2.CReg):
     input = reg.CRegister(1)
     memory = MockMemory()
 
-    result: reg.PyQrackReg = (
+    result: ilist.IList[PyQrackQubit, Literal[2]] = (
         PyQrackInterpreter(simulation, memory=memory, rng_state=rng_state)
         .run(test_atom_loss, (input,))
         .expect()
     )
 
-    assert result.qubit_state[0] is reg.QubitState.Lost
-    assert result.qubit_state[1] is reg.QubitState.Active
+    assert result[0].state is reg.QubitState.Lost
+    assert result[1].state is reg.QubitState.Active
     assert input[0] is reg.Measurement.One

test/pyqrack/test_target.py

@@ -2,9 +2,10 @@
 
 import pytest
 from kirin import ir
+from kirin.dialects import ilist
 
 from bloqade import qasm2
-from bloqade.pyqrack import PyQrack, reg
+from bloqade.pyqrack import PyQrack, PyQrackQubit, reg
 
 
 def test_target():
@@ -23,9 +24,10 @@ def ghz():
 
     q = target.run(ghz)
 
-    assert isinstance(q, reg.PyQrackReg)
+    assert isinstance(q, ilist.IList)
+    assert isinstance(qubit := q[0], PyQrackQubit)
 
-    out = q.sim_reg.out_ket()
+    out = qubit.sim_reg.out_ket()
 
     norm = math.sqrt(sum(abs(ele) ** 2 for ele in out))
     phase = out[0] / abs(out[0])
@@ -56,9 +58,10 @@ def global_h():
     target = PyQrack(3)
     q = target.run(global_h)
 
-    assert isinstance(q, reg.PyQrackReg)
+    assert isinstance(q, ilist.IList)
+    assert isinstance(qubit := q[0], PyQrackQubit)
 
-    out = q.sim_reg.out_ket()
+    out = qubit.sim_reg.out_ket()
 
     # remove global phase introduced by pyqrack
     phase = out[0] / abs(out[0])
@@ -103,9 +106,10 @@ def multiple_registers():
     target = PyQrack(6)
     q1 = target.run(multiple_registers)
 
-    assert isinstance(q1, reg.PyQrackReg)
+    assert isinstance(q1, ilist.IList)
+    assert isinstance(qubit := q1[0], PyQrackQubit)
 
-    out = q1.sim_reg.out_ket()
+    out = qubit.sim_reg.out_ket()
 
     assert out[0] == 1
     for i in range(1, len(out)):
@@ -148,3 +152,19 @@ def measurement_that_errors():
             q = qasm2.qreg(1)
             c = qasm2.creg(1)
             qasm2.measure(q[0], c)
+
+
+def test_qreg_parallel():
+    # test for #161
+    @qasm2.extended
+    def parallel():
+        qreg = qasm2.qreg(4)
+        creg = qasm2.creg(4)
+        qasm2.parallel.u(qreg, theta=math.pi, phi=0.0, lam=0.0)
+        qasm2.measure(qreg, creg)
+        return creg
+
+    target = PyQrack(4)
+    result = target.run(parallel)
+
+    assert result == [reg.Measurement.One] * 4