Deprecate noise amplification option

qiskit_ibm_runtime/options/resilience_options.py

@@ -16,6 +16,7 @@
 from dataclasses import dataclass
 
 from .utils import _flexible
+from ..utils.deprecation import issue_deprecation_msg
 
 ResilienceSupportedOptions = Literal[
     "noise_amplifier",
@@ -47,7 +48,7 @@ class ResilienceOptions:
             Only applicable for ``resilience_level=2``.
             Default: (1, 3, 5).
 
-        noise_amplifier: A noise amplification strategy. One of ``"TwoQubitAmplifier"``,
+        noise_amplifier (DEPRECATED): A noise amplification strategy. One of ``"TwoQubitAmplifier"``,
             ``"GlobalFoldingAmplifier"``, ``"LocalFoldingAmplifier"``, ``"CxAmplifier"``.
             Only applicable for ``resilience_level=2``.
             Default: "TwoQubitAmplifier".
@@ -60,7 +61,7 @@ class ResilienceOptions:
             Default: "LinearExtrapolator".
     """
 
-    noise_amplifier: NoiseAmplifierType = "TwoQubitAmplifier"
+    noise_amplifier: NoiseAmplifierType = None
     noise_factors: Sequence[float] = (1, 3, 5)
     extrapolator: ExtrapolatorType = "LinearExtrapolator"
 
@@ -74,10 +75,21 @@ def validate_resilience_options(resilience_options: dict) -> None:
             ValueError: if extrapolator == "QuarticExtrapolator" and number of noise_factors < 5.
             ValueError: if extrapolator == "CubicExtrapolator" and number of noise_factors < 4.
         """
+        if resilience_options.get("noise_amplifier", None) is not None:
+            issue_deprecation_msg(
+                msg="The 'noise_amplifier' resilience option is deprecated",
+                version="0.12.0",
+                period="1 month",
+                remedy="After the deprecation period, only local folding amplification "
+                "will be supported. "
+                "Refer to https://github.com/qiskit-community/prototype-zne "
+                "for global folding amplification in ZNE.",
+            )
+
         for opt in resilience_options:
             if not opt in get_args(ResilienceSupportedOptions):
                 raise ValueError(f"Unsupported value '{opt}' for resilience.")
-        noise_amplifier = resilience_options.get("noise_amplifier")
+        noise_amplifier = resilience_options.get("noise_amplifier") or "TwoQubitAmplifier"
         if not noise_amplifier in get_args(NoiseAmplifierType):
             raise ValueError(
                 f"Unsupported value {noise_amplifier} for noise_amplifier. "

qiskit_ibm_runtime/utils/deprecation.py

@@ -62,18 +62,21 @@ def deprecate_arguments(deprecated: str, version: str, remedy: str, stacklevel:
     )
 
 
-def issue_deprecation_msg(msg: str, version: str, remedy: str, stacklevel: int = 2) -> None:
+def issue_deprecation_msg(
+    msg: str, version: str, remedy: str, stacklevel: int = 2, period: str = "3 months"
+) -> None:
     """Emit a deprecation warning.
 
     Args:
         msg: Deprecation message.
         version: First release the function is deprecated.
         remedy: User action to take.
         stacklevel: The warning stackevel to use.
+        period: Deprecation period.
     """
     warnings.warn(
         f"{msg} as of qiskit-ibm-runtime {version} "
-        f"and will be removed no sooner than 3 months after the release date. {remedy}",
+        f"and will be removed no sooner than {period} after the release date. {remedy}",
         DeprecationWarning,
         stacklevel=stacklevel + 1,  # Increment to account for this function.
     )

releasenotes/notes/deprecate_noise_amplifier-e656cc98a962a81b.yaml

@@ -0,0 +1,7 @@
+---
+deprecations:
+  - |
+    The ``noise_amplifier`` resilience options is deprecated.
+    After the deprecation period, only local folding amplification will be supported.
+    Refer to https://github.com/qiskit-community/prototype-zne for global folding
+    amplification.

test/unit/test_estimator.py

@@ -12,18 +12,26 @@
 
 """Tests for estimator class."""
 
+import warnings
+
 from qiskit import QuantumCircuit
 from qiskit.quantum_info import SparsePauliOp
 
-from qiskit_ibm_runtime import Estimator, Session
+from qiskit_ibm_runtime import Estimator, Session, Options
 
 from ..ibm_test_case import IBMTestCase
+from ..utils import get_mocked_backend
 from .mock.fake_runtime_service import FakeRuntimeService
 
 
 class TestEstimator(IBMTestCase):
     """Class for testing the Estimator class."""
 
+    def setUp(self) -> None:
+        super().setUp()
+        self.circuit = QuantumCircuit(1, 1)
+        self.observables = SparsePauliOp.from_list([("I", 1)])
+
     def test_unsupported_values_for_estimator_options(self):
         """Test exception when options levels are not supported."""
         options_bad = [
@@ -34,10 +42,30 @@ def test_unsupported_values_for_estimator_options(self):
             service=FakeRuntimeService(channel="ibm_quantum", token="abc"),
             backend="common_backend",
         ) as session:
-            circuit = QuantumCircuit(1, 1)
-            obs = SparsePauliOp.from_list([("I", 1)])
             for bad_opt in options_bad:
                 inst = Estimator(session=session)
                 with self.assertRaises(ValueError) as exc:
-                    _ = inst.run(circuit, observables=obs, **bad_opt)
+                    _ = inst.run(self.circuit, observables=self.observables, **bad_opt)
                 self.assertIn(list(bad_opt.keys())[0], str(exc.exception))
+
+    def test_deprecated_noise_amplifier(self):
+        """Test noise_amplifier deprecation."""
+        opt = Options()
+        opt.resilience.noise_amplifier = "GlobalFoldingAmplifier"
+
+        with warnings.catch_warnings(record=True) as warn:
+            warnings.simplefilter("always")
+            estimator = Estimator(backend=get_mocked_backend(), options=opt)
+            estimator.run(self.circuit, self.observables)
+            self.assertEqual(len(warn), 1, "Deprecation warning not found.")
+            self.assertIn("noise_amplifier", str(warn[-1].message))
+
+    def test_deprecated_noise_amplifier_run(self):
+        """Test noise_amplifier deprecation in run."""
+
+        with warnings.catch_warnings(record=True) as warn:
+            warnings.simplefilter("always")
+            estimator = Estimator(backend=get_mocked_backend())
+            estimator.run(self.circuit, self.observables, noise_amplifier="GlobalFoldingAmplifier")
+            self.assertEqual(len(warn), 1, "Deprecation warning not found.")
+            self.assertIn("noise_amplifier", str(warn[-1].message))

test/unit/test_ibm_primitives.py

@@ -511,7 +511,7 @@ def test_accept_level_1_options(self):
             {"shots": 10},
             {"seed_simulator": 123},
             {"skip_transpilation": True, "log_level": "ERROR"},
-            {"initial_layout": [1, 2], "shots": 100, "noise_amplifier": "CxAmplifier"},
+            {"initial_layout": [1, 2], "shots": 100, "noise_factors": (0, 2, 4)},
         ]
 
         expected_list = [Options(), Options(), Options(), Options(), Options()]
@@ -521,7 +521,7 @@ def test_accept_level_1_options(self):
         expected_list[3].environment.log_level = "ERROR"
         expected_list[4].transpilation.initial_layout = [1, 2]
         expected_list[4].execution.shots = 100
-        expected_list[4].resilience.noise_amplifier = "CxAmplifier"
+        expected_list[4].resilience.noise_factors = (0, 2, 4)
 
         session = MagicMock(spec=MockSession)
         primitives = [Sampler, Estimator]
@@ -603,7 +603,6 @@ def test_default_error_levels(self):
     def test_resilience_options(self):
         """Test resilience options."""
         options_dicts = [
-            {"resilience": {"noise_amplifier": "NoAmplifier"}},
             {"resilience": {"extrapolator": "NoExtrapolator"}},
             {
                 "resilience": {

test/unit/test_options.py

@@ -135,7 +135,7 @@ def test_program_inputs(self):
             execution={"shots": 100},
             environment={"log_level": "DEBUG"},
             simulator={"noise_model": noise_model},
-            resilience={"noise_amplifier": "GlobalFoldingAmplifier"},
+            resilience={"noise_factors": (0, 2, 4)},
             foo="foo",
             bar="bar",
         )
@@ -154,7 +154,7 @@ def test_program_inputs(self):
             },
             "resilience_settings": {
                 "level": 2,
-                "noise_amplifier": "GlobalFoldingAmplifier",
+                "noise_factors": (0, 2, 4),
             },
             "foo": "foo",
         }
@@ -175,7 +175,7 @@ def test_init_options_with_dictionary(self):
                 "transpilation": {"initial_layout": [1, 2], "layout_method": "trivial"},
                 "execution": {"shots": 100},
             },
-            {"resilience": {"noise_amplifier": "GlobalFoldingAmplifier"}},
+            {"resilience": {"noise_factors": (0, 2, 4)}},
             {"environment": {"log_level": "ERROR"}},
         ]
 
@@ -201,7 +201,7 @@ def test_unsupported_options(self):
             "environment": {"log_level": "DEBUG"},
             "simulator": {"noise_model": "model"},
             "resilience": {
-                "noise_amplifier": "GlobalFoldingAmplifier",
+                "noise_factors": (0, 2, 4),
                 "extrapolator": "LinearExtrapolator",
             },
         }

test/utils.py

@@ -17,7 +17,7 @@
 import time
 import unittest
 from unittest import mock
-from typing import Dict, Optional
+from typing import Dict, Optional, Any
 from datetime import datetime
 
 from qiskit.circuit import QuantumCircuit
@@ -247,3 +247,11 @@ def create_faulty_backend(
     )
     out_backend.properties = lambda: BackendProperties.from_dict(properties)  # type: ignore
     return out_backend
+
+
+def get_mocked_backend(name: str = "ibm_gotham") -> Any:
+    """Return a mock backend."""
+    mock_backend = mock.MagicMock(spec=IBMBackend)
+    mock_backend.name = name
+    mock_backend._instance = None
+    return mock_backend