fix(adjoint): only trigger symmetric adjoint simulation warning when grouping by more than 1 port

Author: Gregory Roberts

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 - Fixed missing amplitude factor and handling of negative normal direction case when making adjoint sources from `DiffractionMonitor`.
 - Improved the robustness of batch jobs. The batch state, including all `task_ids`, is now saved to `batch.hdf5` immediately after upload. This fixes an issue where an interrupted batch (e.g., due to a kernel crash or network loss) would be unrecoverable.
+- Fixed warning for running symmetric adjoint simulations by port to not trigger when there is a single port.
 
 ## [2.9.0] - 2025-08-04
 

tidy3d/components/data/sim_data.py

@@ -1192,7 +1192,7 @@ def _process_adjoint_sources(self, adj_srcs: list[SourceType]) -> list[AdjointSo
             # warn if the forward simulation had symmetry and we are grouping by port, which
             # which means the individual adjoint simulations may not respect the original symmetry
             #
-            if np.any(np.abs(self.simulation.symmetry) > 0):
+            if np.any(np.abs(self.simulation.symmetry) > 0) and (num_ports > 1):
                 log.warning(
                     "The adjoint simulations for this problem are being broken into "
                     "multiple simulations that may not individually respect the symmetry of the "