InstructionDurations from BackendV2

qiskit/transpiler/instruction_durations.py

@@ -17,6 +17,7 @@
 import qiskit.circuit
 from qiskit.circuit import Barrier, Delay, Instruction, ParameterExpression
 from qiskit.circuit.duration import duration_in_dt
+from qiskit.providers import Backend, BackendV1, BackendV2
 from qiskit.providers import Backend
 from qiskit.providers.backend import BackendV2
 from qiskit.transpiler.exceptions import TranspilerError
@@ -71,33 +72,41 @@ def from_backend(cls, backend: Backend):
 
         Returns:
             InstructionDurations: The InstructionDurations constructed from backend.
-
-        Raises:
-            TranspilerError: If dt and dtm is different in the backend.
         """
+
         # All durations in seconds in gate_length
         if isinstance(backend, BackendV2):
             return backend.target.durations()
 
         instruction_durations = []
-        backend_properties = backend.properties()
-        if hasattr(backend_properties, "_gates"):
-            for gate, insts in backend_properties._gates.items():
-                for qubits, props in insts.items():
-                    if "gate_length" in props:
-                        gate_length = props["gate_length"][0]  # Throw away datetime at index 1
-                        instruction_durations.append((gate, qubits, gate_length, "s"))
-            for q, props in backend.properties()._qubits.items():
-                if "readout_length" in props:
-                    readout_length = props["readout_length"][0]  # Throw away datetime at index 1
-                    instruction_durations.append(("measure", [q], readout_length, "s"))
-
-        try:
-            dt = backend.configuration().dt
-        except AttributeError:
-            dt = None
-
-        return cls(instruction_durations, dt=dt)
+        return_durations = None
+
+        # Logic to handle if backend is sub-class of old BackendV1
+        if isinstance(backend, BackendV1):
+            backend_properties = backend.properties()
+            if hasattr(backend_properties, "_gates"):
+                for gate, insts in backend_properties._gates.items():
+                    for qubits, props in insts.items():
+                        if "gate_length" in props:
+                            gate_length = props["gate_length"][0]  # Ignore datetime at index 1
+                            instruction_durations.append((gate, qubits, gate_length, "s"))
+                for q, props in backend.properties()._qubits.items():
+                    if "readout_length" in props:
+                        readout_length = props["readout_length"][0]  # Ignore datetime at index 1
+                        instruction_durations.append(("measure", [q], readout_length, "s"))
+
+            try:
+                dt = backend.configuration().dt
+            except AttributeError:
+                dt = None
+
+            return_durations = cls(instruction_durations, dt=dt)
+
+        # Logic to handle if backend is sub-class is BackendV2
+        elif isinstance(backend, BackendV2):
+            return_durations = backend.target.durations()
+
+        return return_durations
 
     def update(self, inst_durations: "InstructionDurationsType" | None, dt: float = None):
         """Update self with inst_durations (inst_durations overwrite self).

releasenotes/notes/Add_support_for_BackendV2_in_instruction_durations_from_backend-9ce722879c870377.yaml

@@ -0,0 +1,15 @@
+---
+features:
+  - |
+    Support for :class:`.BackendV2` in :meth:`.InstructionDurations.from_backend` is added.
+
+    Users can have an object of :class:`.InstructionDurations` using :class:`.BackendV2`
+    from :meth:`.InstructionDurations.from_backend` with followig code.
+
+    .. code-block:: python
+
+      from qiskit.providers.fake_provider import FakePerth
+      from qiskit.transpiler import InstructionDurations
+      backendV2 = FakePerth()
+
+      inst_dur = InstructionDurations.from_backend(backendV2)

test/python/transpiler/test_instruction_durations.py

@@ -13,8 +13,9 @@
 # pylint: disable=missing-function-docstring
 
 """Test InstructionDurations class."""
-
+from copy import deepcopy
 from qiskit.circuit import Delay, Parameter
+from qiskit.providers.fake_provider import Fake7QPulseV1, GenericBackendV2
 from qiskit.providers.fake_provider import Fake27QPulseV1
 from qiskit.providers.fake_provider import GenericBackendV2
 from qiskit.transpiler.exceptions import TranspilerError
@@ -61,21 +62,9 @@ def test_update_with_parameters(self):
         durations = InstructionDurations(
             [("rzx", (0, 1), 150, (0.5,)), ("rzx", (0, 1), 300, (1.0,))]
         )
-
         self.assertEqual(durations.get("rzx", [0, 1], parameters=[0.5]), 150)
         self.assertEqual(durations.get("rzx", [0, 1], parameters=[1.0]), 300)
 
-    def _find_gate_with_length(self, backend):
-        """Find a gate that has gate length."""
-        props = backend.properties()
-        for gate in props.gates:
-            try:
-                if props.gate_length(gate.gate, 0):
-                    return gate.gate
-            except Exception:  # pylint: disable=broad-except
-                pass
-        raise ValueError("Unable to find a gate with gate length.")
-
     def test_can_get_unbounded_duration_without_unit_conversion(self):
         param = Parameter("t")
         parameterized_delay = Delay(param, "dt")