Merge pull request #42 from TohgoRena/fix/qiskit-stats-counters

Fix/qiskit stats counters

Author: snuffkin

src/tranqu/transpiler/qiskit_stats_extractor.py

@@ -1,9 +1,26 @@
-from qiskit import QuantumCircuit  # type: ignore[import-untyped]
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, ClassVar
+
+if TYPE_CHECKING:
+    from qiskit import QuantumCircuit  # type: ignore[import-untyped]
+from qiskit.circuit.controlflow import (  # type: ignore[import-untyped]
+    CONTROL_FLOW_OP_NAMES,
+)
 
 
 class QiskitStatsExtractor:
     """Extract statistical information from Qiskit quantum circuits."""
 
+    _NON_GATE_OPERATION: ClassVar[set[str]] = {
+        "measure",
+        "reset",
+        "barrier",
+        "delay",
+        "initialize",
+        *CONTROL_FLOW_OP_NAMES,  # 'if_else','for_loop','while_loop','switch_case'
+    }
+
     def extract_stats_from(self, program: QuantumCircuit) -> dict[str, int]:
         """Extract statistical information from a Qiskit quantum circuit.
 
@@ -16,16 +33,46 @@ def extract_stats_from(self, program: QuantumCircuit) -> dict[str, int]:
         """
         stats = {}
         stats["n_qubits"] = program.num_qubits
-        stats["n_gates"] = len(program.data)
+        stats["n_gates"] = self._count_gates(program)
         stats["n_gates_1q"] = self._count_single_qubit_gates(program)
         stats["n_gates_2q"] = self._count_two_qubit_gates(program)
         stats["depth"] = program.depth()
         return stats
 
+    @staticmethod
+    def _count_gates(program: QuantumCircuit) -> int:
+        # sum non_gate operation
+        return sum(
+            1
+            for instruction in program.data
+            if instruction.operation.name
+            not in QiskitStatsExtractor._NON_GATE_OPERATION
+        )
+
     @staticmethod
     def _count_single_qubit_gates(program: QuantumCircuit) -> int:
-        return sum(1 for instruction in program.data if len(instruction.qubits) == 1)
+        data = program.data
+        count = 0
+        for instruction in data:
+            # is 1 qubit?
+            if len(instruction.qubits) != 1:
+                continue
+            # is non gate opration?
+            if instruction.operation.name in QiskitStatsExtractor._NON_GATE_OPERATION:
+                continue
+            count += 1
+        return count
 
     @staticmethod
     def _count_two_qubit_gates(program: QuantumCircuit) -> int:
-        return sum(1 for instruction in program.data if len(instruction.qubits) == 2)  # noqa: PLR2004
+        data = program.data
+        count = 0
+        for instruction in data:
+            # is 2 qubit?
+            if len(instruction.qubits) != 2:  # noqa: PLR2004
+                continue
+            # is non gate opration?
+            if instruction.operation.name in QiskitStatsExtractor._NON_GATE_OPERATION:
+                continue
+            count += 1
+        return count

tests/tranqu/transpiler/test_qiskit_stats_extractor.py

@@ -0,0 +1,67 @@
+# mypy: disable-error-code="import-untyped"
+
+from __future__ import annotations
+
+from qiskit import QuantumCircuit
+
+from tranqu.transpiler.qiskit_stats_extractor import QiskitStatsExtractor
+
+
+class TestQiskitStatsExtractor:
+    def test_simple_circuit_counts(self) -> None:
+        """Check that basic 1-qubit / 2-qubit gate counts are correct."""
+        circuit = QuantumCircuit(2)
+        circuit.h(0)
+        circuit.x(0)
+        circuit.cx(0, 1)
+
+        extractor = QiskitStatsExtractor()
+        stats = extractor.extract_stats_from(circuit)
+
+        # Number of qubits
+        assert stats["n_qubits"] == 2
+        # Only H, X, and CX (3 operations) are counted as gates
+        assert stats["n_gates"] == 3
+        # 1-qubit gates: H and X (2 operations)
+        assert stats["n_gates_1q"] == 2
+        # 2-qubit gates: only CX (1 operation)
+        assert stats["n_gates_2q"] == 1
+        # Depth should match QuantumCircuit.depth()
+        assert stats["depth"] == circuit.depth()
+
+    def test_non_gate_operations_are_ignored(self) -> None:
+        """Check that non-gate operations."""
+        circuit = QuantumCircuit(2, 2)
+        # Gate
+        circuit.h(0)
+        circuit.x(0)
+        circuit.cx(0, 1)
+        # Various non-gate operations
+        circuit.barrier()
+        circuit.measure(0, 0)
+        circuit.reset(1)
+        circuit.delay(100, 0)
+        circuit.initialize([1, 0], 0)
+
+        extractor = QiskitStatsExtractor()
+        stats = extractor.extract_stats_from(circuit)
+
+        # Number of qubits is still correct
+        assert stats["n_qubits"] == 2
+        # Only H, X, and CX (3 operations) are counted as gates
+        assert stats["n_gates"] == 3
+        assert stats["n_gates_1q"] == 2
+        assert stats["n_gates_2q"] == 1
+
+    def test_empty_circuit(self) -> None:
+        """Check that an empty circuit does not raise and all counts are zero."""
+        circuit = QuantumCircuit(3)
+
+        extractor = QiskitStatsExtractor()
+        stats = extractor.extract_stats_from(circuit)
+
+        assert stats["n_qubits"] == 3
+        assert stats["n_gates"] == 0
+        assert stats["n_gates_1q"] == 0
+        assert stats["n_gates_2q"] == 0
+        assert stats["depth"] == 0