From 51a55afcb28449ada7ffc84f2e568e6035a971e9 Mon Sep 17 00:00:00 2001
From: Momchil Minkov <momchil@flexcompute.com>
Date: Fri, 13 Dec 2024 14:24:27 +0100
Subject: [PATCH] Adding ElectromagneticFieldData._check_fields_stored

---
 tidy3d/components/data/monitor_data.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tidy3d/components/data/monitor_data.py b/tidy3d/components/data/monitor_data.py
index b1cecf978..6775e2afa 100644
--- a/tidy3d/components/data/monitor_data.py
+++ b/tidy3d/components/data/monitor_data.py
@@ -933,6 +933,15 @@ def time_reversed_copy(self) -> FieldData:
                 new_data[comp] = np.conj(field)
         return self.copy(update=new_data)
 
+    def _check_fields_stored(self, components: list[str]):
+        """Check that all requested field components are stored in the data."""
+        missing_comps = [comp for comp in components if comp not in self.field_components.keys()]
+        if len(missing_comps) > 0:
+            raise DataError(
+                f"Field components {missing_comps} not included in this data object. Use "
+                "the 'fields' argument of a field monitor to select which components are stored."
+            )
+
 
 class FieldData(FieldDataset, ElectromagneticFieldData):
     """