♻️ Refactor RL actions by SDK

CHANGELOG.md

@@ -11,6 +11,8 @@ This project adheres to [Semantic Versioning], with the exception that minor rel
 
 ### Changed
 
+- ♻️ Restructure existing RL passes into SDK-level action modules, including their wrapper logic ([#644]) ([**@flowerthrower**])
+- 🐛 Support BQSKit conversion of IQM's native `r` gate ([#679]) ([**@flowerthrower**])
 - 🔧 Replace `mypy` with `ty` ([#572]) ([**@denialhaag**])
 - 🐛 Fix instruction duration unit in estimated success probability calculation ([#445]) ([**@Shaobo-Zhou**])
 - ✨ Remove support for custom names of trained models ([#489]) ([**@bachase**])
@@ -50,6 +52,8 @@ _📚 Refer to the [GitHub Release Notes](https://github.com/munich-quantum-tool
 [#489]: https://github.com/munich-quantum-toolkit/predictor/pull/489
 [#445]: https://github.com/munich-quantum-toolkit/predictor/pull/445
 [#421]: https://github.com/munich-quantum-toolkit/predictor/pull/421
+[#644]: https://github.com/munich-quantum-toolkit/predictor/pull/644
+[#679]: https://github.com/munich-quantum-toolkit/predictor/pull/679
 [#406]: https://github.com/munich-quantum-toolkit/predictor/pull/406
 [#405]: https://github.com/munich-quantum-toolkit/predictor/pull/405
 [#403]: https://github.com/munich-quantum-toolkit/predictor/pull/403

src/mqt/predictor/reward.py

@@ -23,7 +23,6 @@
 
 if TYPE_CHECKING:
     from qiskit import QuantumCircuit
-    from qiskit.circuit import QuantumRegister, Qubit
     from qiskit.transpiler import Target
     from sklearn.ensemble import RandomForestRegressor
 
@@ -62,44 +61,22 @@ def expected_fidelity(qc: QuantumCircuit, device: Target, precision: int = 10) -
 
         if gate_type != "barrier":
             assert len(qargs) in [1, 2]
-            first_qubit_idx = calc_qubit_index(qargs, qc.qregs, 0)
+            first_qubit_idx = qc.find_bit(qargs[0]).index
 
             if len(qargs) == 1:
                 specific_fidelity = 1 - device[gate_type][first_qubit_idx,].error
             else:
-                second_qubit_idx = calc_qubit_index(qargs, qc.qregs, 1)
-                specific_fidelity = 1 - device[gate_type][first_qubit_idx, second_qubit_idx].error
-
+                second_qubit_idx = qc.find_bit(qargs[1]).index
+                try:
+                    specific_fidelity = 1 - device[gate_type][first_qubit_idx, second_qubit_idx].error
+                except KeyError:
+                    msg = f"Error rate for gate {gate_type} on qubits {first_qubit_idx} and {second_qubit_idx} not found in device properties."
+                    raise KeyError(msg) from None
             res *= specific_fidelity
 
     return float(np.round(res, precision).item())
 
 
-def calc_qubit_index(qargs: list[Qubit], qregs: list[QuantumRegister], index: int) -> int:
-    """Calculates the global qubit index for a given quantum circuit and qubit index.
-
-    Arguments:
-        qargs: The qubits of the quantum circuit.
-        qregs: The quantum registers of the quantum circuit.
-        index: The index of the qubit in the qargs list.
-
-    Returns:
-        The global qubit index of the given qubit in the quantum circuit.
-
-    Raises:
-        ValueError: If the qubit index is not found in the quantum registers.
-    """
-    offset = 0
-    for reg in qregs:
-        if qargs[index] not in reg:
-            offset += reg.size
-        else:
-            qubit_index: int = offset + reg.index(qargs[index])
-            return qubit_index
-    error_msg = f"Global qubit index for local qubit {index} index not found."
-    raise ValueError(error_msg)
-
-
 def estimated_success_probability(qc: QuantumCircuit, device: Target, precision: int = 10) -> float:
     """Calculates the estimated success probability of a given quantum circuit on a given device.
 
@@ -125,7 +102,7 @@ def estimated_success_probability(qc: QuantumCircuit, device: Target, precision:
         if gate_type == "barrier" or gate_type == "id":
             continue
         assert len(qargs) in (1, 2)
-        first_qubit_idx = calc_qubit_index(qargs, qc.qregs, 0)
+        first_qubit_idx = qc.find_bit(qargs[0]).index
         active_qubits.add(first_qubit_idx)
 
         if len(qargs) == 1:  # single-qubit gate
@@ -140,7 +117,7 @@ def estimated_success_probability(qc: QuantumCircuit, device: Target, precision:
             ))
             exec_time_per_qubit[first_qubit_idx] += duration
         else:  # multi-qubit gate
-            second_qubit_idx = calc_qubit_index(qargs, qc.qregs, 1)
+            second_qubit_idx = qc.find_bit(qargs[1]).index
             active_qubits.add(second_qubit_idx)
             duration = device[gate_type][first_qubit_idx, second_qubit_idx].duration
             op_times.append((gate_type, [first_qubit_idx, second_qubit_idx], duration, "s"))
@@ -191,7 +168,7 @@ def estimated_success_probability(qc: QuantumCircuit, device: Target, precision:
             continue
 
         assert len(qargs) in (1, 2)
-        first_qubit_idx = calc_qubit_index(qargs, qc.qregs, 0)
+        first_qubit_idx = scheduled_circ.find_bit(qargs[0]).index
 
         if len(qargs) == 1:
             if gate_type == "measure":
@@ -213,7 +190,7 @@ def estimated_success_probability(qc: QuantumCircuit, device: Target, precision:
                 continue
             res *= 1 - device[gate_type][first_qubit_idx,].error
         else:
-            second_qubit_idx = calc_qubit_index(qargs, qc.qregs, 1)
+            second_qubit_idx = scheduled_circ.find_bit(qargs[1]).index
             res *= 1 - device[gate_type][first_qubit_idx, second_qubit_idx].error
 
     if qiskit_version >= "2.0.0":