Suppress numpy warning during uarray creation

qiskit_experiments/data_processing/data_processor.py

@@ -261,10 +261,14 @@ def _data_extraction(self, data: Union[Dict, List[Dict]]) -> np.ndarray:
             # The output data format is a standard ndarray with dtype=object with
             # arbitrary shape [n_circuits, ...] depending on the measurement setup.
             nominal_values = np.asarray(data_to_process, float)
-            return unp.uarray(
-                nominal_values=nominal_values,
-                std_devs=np.full_like(nominal_values, np.nan, dtype=float),
-            )
+            with np.errstate(invalid="ignore"):
+                # Setting std_devs to NaN will trigger floating point exceptions
+                # which we can ignore. See https://stackoverflow.com/q/75656026
+                uarray = unp.uarray(
+                    nominal_values=nominal_values,
+                    std_devs=np.full_like(nominal_values, np.nan, dtype=float),
+                )
+            return uarray
         else:
             # Likely level2 counts or level2 memory data. Cannot be typecasted to ufloat.
             # The output data format is a standard ndarray with dtype=object with

releasenotes/notes/uarray-warning-d4c38566a510e58f.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    A ``RuntimeWarning`` will no longer be generated by numpy when running a
+    data processor on level one data. See `#1071
+    <https://github.com/Qiskit/qiskit-experiments/issues/1071>_`.