BUG: raise an error if integration is attempted over no unobserved he…

…terogeneity
jeffgortmaker · Jul 23, 2022 · 8210fdd · 8210fdd
1 parent 0626c96
commit 8210fdd
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/pyblp/primitives.py b/pyblp/primitives.py
@@ -441,6 +441,10 @@ def __new__(
         else:
             if not isinstance(integration, Integration):
                 raise ValueError("integration must be None or an Integration instance.")
+            if parameters.nonzero_sigma_index.sum() == 0:
+                raise ValueError(
+                    "There is no unobserved heterogeneity over which to integrate, so integration must be None."
+                )
 
             # duplicate observations by as many rows as there are built nodes
             micro_ids, nodes, weights = integration._build_many(