[docs] clarify user-defined functions return scalars

jump-dev · Apr 9, 2021 · d19090d · d19090d
1 parent b6d9ddf
commit d19090d
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/docs/src/manual/nlp.md b/docs/src/manual/nlp.md
@@ -274,6 +274,10 @@ In addition to this list of functions, it is possible to register custom
     a function is not needed. Two exceptions are if you want to provide custom
     derivatives, or if the function is not available in the scope of the
     nonlinear expression.
+
+!!! warning
+    User-defined functions must return a scalar output. For a work-around, see
+    [User-defined functions with vector outputs](@ref).
 
 ### Automatic differentiation