Update docs and comments

Author: Shaobo-Zhou

CHANGELOG.md

@@ -11,7 +11,7 @@ This project adheres to [Semantic Versioning], with the exception that minor rel
 
 ### Changed
 
-- 🔧 Changed test circuit level for RL predictor from ALG to INDEP
+- 🔧 Changed test circuit level for RL predictor from ALG to INDEP ([#449]) ([**@Shaobo-Zhou**])
 - ✨ Remove support for custom names of trained models ([#489]) ([**@bachase**])
 - 🔥 Drop support for x86 macOS systems ([#421]) ([**@denialhaag**])
 

noxfile.py

@@ -18,7 +18,6 @@
 import argparse
 import contextlib
 import os
-import pathlib
 import shutil
 import tempfile
 from typing import TYPE_CHECKING
@@ -61,21 +60,6 @@ def lint(session: nox.Session) -> None:
     session.run("pre-commit", "run", "--all-files", *session.posargs, external=True)
 
 
-def _cleanup(session: nox.Session) -> None:
-    """Remove this session's virtualenv to save disk space in CI."""
-    version = session.python
-    if version != "3.13":  # keep cache for last run
-        venv_dir = session.virtualenv.location
-        if venv_dir and pathlib.Path(venv_dir).exists():
-            shutil.rmtree(venv_dir, ignore_errors=True)
-            session.log(f"Cleaned up {venv_dir}")
-        shutil.rmtree(pathlib.Path("~/.cache").expanduser(), ignore_errors=True)
-        gha_temp = pathlib.Path("/home/runner/work/_temp/setup-uv-cache")
-        if gha_temp.exists():
-            shutil.rmtree(gha_temp, ignore_errors=True)
-            session.log(f"Cleaned GitHub Actions uv temp cache at {gha_temp}")
-
-
 def _run_tests(
     session: nox.Session,
     *,
@@ -109,8 +93,6 @@ def _run_tests(
 def tests(session: nox.Session) -> None:
     """Run the test suite."""
     _run_tests(session)
-    if os.environ.get("CI"):
-        _cleanup(session)
 
 
 @nox.session(python=PYTHON_ALL_VERSIONS, reuse_venv=True, venv_backend="uv", default=True)

src/mqt/predictor/rl/helper.py

@@ -17,7 +17,7 @@
 import numpy as np
 from qiskit import QuantumCircuit
 
-from mqt.predictor.utils import calc_supermarq_features, get_openqasm_gates
+from mqt.predictor.utils import calc_supermarq_features, get_rl_openqasm_gates
 
 if TYPE_CHECKING:
     from numpy.random import Generator
@@ -71,7 +71,7 @@ def get_state_sample(max_qubits: int, path_training_circuits: Path, rng: Generat
 
 def dict_to_featurevector(gate_dict: dict[str, int]) -> dict[str, float]:
     """Calculates and returns a normalized feature vector of a given quantum circuit gate dictionary."""
-    res_dct = dict.fromkeys(get_openqasm_gates(), 0.0)
+    res_dct = dict.fromkeys(get_rl_openqasm_gates(), 0.0)
     exclude_from_total = {"barrier"}
     total = sum(val for key, val in gate_dict.items() if key not in exclude_from_total)
 

src/mqt/predictor/rl/predictorenv.py

@@ -82,7 +82,7 @@
     postprocess_vf2postlayout,
     prepare_noise_data,
 )
-from mqt.predictor.utils import get_openqasm_gates
+from mqt.predictor.utils import get_rl_openqasm_gates
 
 logger = logging.getLogger("mqt-predictor")
 
@@ -178,7 +178,7 @@ def __init__(
         self.has_parameterized_gates = False
         self.rng = np.random.default_rng(10)
 
-        gate_spaces = {g: Box(low=0, high=1, shape=(1,), dtype=np.float32) for g in get_openqasm_gates()}
+        gate_spaces = {g: Box(low=0, high=1, shape=(1,), dtype=np.float32) for g in get_rl_openqasm_gates()}
 
         spaces = {
             "num_qubits": Discrete(self.device.num_qubits + 1),
@@ -392,7 +392,15 @@ def fom_aware_compile(
                 prop_set = dict(pm.property_set)
 
                 try:
-                    # Synthesize for lookahead fidelity (Mapping could insert non-local SWAP gates)
+                    # For fidelity-based metrics, do a cheap "lookahead" synthesis step:
+                    # routing may have introduced non-native SWAPs, so we translate the
+                    # circuit into the device's native basis before evaluating the metric.
+                    #
+                    # Note:
+                    # - BasisTranslator *only* performs basis conversion; it does not optimize.
+                    # - This isolates the effect of mapping (inserted SWAPs) on fidelity
+                    #   without conflating it with further optimizations.
+
                     if maximize:
                         synth_pass = PassManager([
                             BasisTranslator(StandardEquivalenceLibrary, target_basis=device.operation_names)

src/mqt/predictor/utils.py

@@ -145,7 +145,7 @@ def calc_supermarq_features(
     )
 
 
-def get_openqasm_gates() -> list[str]:
+def get_rl_openqasm_gates() -> list[str]:
     """Returns a list of all quantum gates within the openQASM 2.0 standard header."""
     # according to https://github.com/Qiskit/qiskit-terra/blob/main/qiskit/qasm/libs/qelib1.inc
     # u,u0,u1,u2,u3 gates are excluded as they are not meaningful as RL features