Add checks for parameter expressions with gen3-turbo runtime. (#2046)

* Add checks for parameter expressions with gen3-turbo runtime.

* Workaround for linting failures.

---------

Co-authored-by: Ian Hincks <[email protected]>

qiskit_ibm_runtime/base_primitive.py

@@ -27,7 +27,11 @@
 from .options.utils import merge_options_v2
 from .runtime_job_v2 import RuntimeJobV2
 from .ibm_backend import IBMBackend
-from .utils import validate_isa_circuits, validate_no_dd_with_dynamic_circuits
+from .utils import (
+    validate_isa_circuits,
+    validate_no_dd_with_dynamic_circuits,
+    validate_no_param_expressions_gen3_runtime,
+)
 from .utils.default_session import get_cm_session
 from .utils.deprecation import issue_deprecation_msg
 from .utils.utils import is_simulator
@@ -170,6 +174,7 @@ def _run(self, pubs: Union[list[EstimatorPub], list[SamplerPub]]) -> RuntimeJobV
         runtime_options = self._options_class._get_runtime_options(options_dict)
 
         validate_no_dd_with_dynamic_circuits([pub.circuit for pub in pubs], self.options)
+        validate_no_param_expressions_gen3_runtime([pub.circuit for pub in pubs], self.options)
         if self._backend:
             for pub in pubs:
                 if getattr(self._backend, "target", None) and not is_simulator(self._backend):

qiskit_ibm_runtime/utils/__init__.py

@@ -33,6 +33,7 @@
     validate_no_dd_with_dynamic_circuits,
     validate_isa_circuits,
     validate_job_tags,
+    validate_no_param_expressions_gen3_runtime,
 )
 
 from .json import RuntimeEncoder, RuntimeDecoder, to_base64_string

qiskit_ibm_runtime/utils/utils.py

@@ -29,7 +29,7 @@
     IAMAuthenticator,
 )
 from ibm_platform_services import ResourceControllerV2  # pylint: disable=import-error
-from qiskit.circuit import QuantumCircuit, ControlFlowOp, ParameterExpression
+from qiskit.circuit import QuantumCircuit, ControlFlowOp, ParameterExpression, Parameter
 from qiskit.transpiler import Target
 from qiskit.providers.backend import BackendV1, BackendV2
 from .deprecation import deprecate_function
@@ -130,6 +130,16 @@ def are_circuits_dynamic(circuits: List[QuantumCircuit], qasm_default: bool = Tr
     return False
 
 
+def has_param_expressions(circuits: List[QuantumCircuit]) -> bool:
+    """Checks if the input circuits contain `ParameterExpression`s"""
+    for circuit in circuits:
+        for instruction in circuit.data:
+            for p in instruction.operation.params:
+                if isinstance(p, ParameterExpression) and not isinstance(p, Parameter):
+                    return True
+    return False
+
+
 def get_iam_api_url(cloud_url: str) -> str:
     """Computes the IAM API URL for the given IBM Cloud URL."""
     parsed_url = urlparse(cloud_url)

qiskit_ibm_runtime/utils/validations.py

@@ -19,7 +19,11 @@
 from qiskit.transpiler import Target
 from qiskit.primitives.containers.sampler_pub import SamplerPub
 from qiskit.primitives.containers.estimator_pub import EstimatorPub
-from qiskit_ibm_runtime.utils.utils import is_isa_circuit, are_circuits_dynamic
+from qiskit_ibm_runtime.utils.utils import (
+    is_isa_circuit,
+    are_circuits_dynamic,
+    has_param_expressions,
+)
 from qiskit_ibm_runtime.exceptions import IBMInputValueError
 
 
@@ -127,3 +131,24 @@ def validate_job_tags(job_tags: Optional[List[str]]) -> None:
         not isinstance(job_tags, list) or not all(isinstance(tag, str) for tag in job_tags)
     ):
         raise IBMInputValueError("job_tags needs to be a list of strings.")
+
+
+def validate_no_param_expressions_gen3_runtime(
+    circuits: List[QuantumCircuit], options: Any
+) -> None:
+    """Validate that when the gen3 runtime is used, no circuit in the pubs contain
+    ParameterExpressions.
+
+    Args:
+        circuits: A list of QuantumCircuits
+        options: The runtime options
+    """
+    if (
+        not hasattr(options.experimental, "get")
+        or options.experimental.get("execution_path", None) != "gen3-turbo"
+    ):
+        return
+    if has_param_expressions(circuits):
+        raise IBMInputValueError(
+            "The gen3-turbo runtime currently does not support parameter expressions"
+        )

test/unit/test_sampler.py

@@ -322,6 +322,36 @@ def test_rzz_validates_only_for_fixed_angles(self):
             # Should run without an error
             SamplerV2(backend).run(pubs=[(circ, [0.5])])
 
+    def test_param_expressions_gen3_runtime(self):
+        """Verify that parameter expressions are not used in combination with the gen3-turbo
+        execution path."""
+        backend = FakeCusco()
+        x = Parameter("x")
+        y = Parameter("y")
+        # pylint: disable-next=unexpected-keyword-arg
+        opts = SamplerOptions(experimental={"execution_path": "gen3-turbo"})
+
+        with self.subTest("float"):
+            circ = QuantumCircuit(1, 1)
+            circ.rz(x, 0)
+            circ.measure(0, 0)
+            bound_circ = circ.assign_parameters({x: 0.1})
+            # expect no error (parameter is bound to a float)
+            SamplerV2(backend, opts).run(pubs=[(bound_circ,)])
+            # expect no error (simple parameter, not a parameter expression)
+            SamplerV2(backend, opts).run(pubs=[(circ, [0.2])])
+
+        with self.subTest("parameter expressions"):
+            circ = QuantumCircuit(1, 1)
+            circ.rz(x + 2 * y, 0)
+            circ.measure(0, 0)
+            with self.assertRaises(IBMInputValueError):
+                SamplerV2(backend, opts).run(pubs=[(circ, [0.1, 0.2])])
+            # without the gen3-turbo execution path, we expect no error
+            # pylint: disable-next=unsupported-assignment-operation
+            opts.experimental["execution_path"] = ""
+            SamplerV2(backend, opts).run(pubs=[(circ, [0.1, 0.2])])
+
     @data(
         "classified",
         "kerneled",