From 19803b013f924dcd291d119844bbae89db575867 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Wed, 8 Apr 2026 22:12:16 +0200
Subject: [PATCH] Add nonlinear_model function

---
 src/Nonlinear/model.jl | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/Nonlinear/model.jl b/src/Nonlinear/model.jl
index b570a0dcc3..023640625e 100644
--- a/src/Nonlinear/model.jl
+++ b/src/Nonlinear/model.jl
@@ -77,6 +77,16 @@ function set_objective(model::Model, ::Nothing)
     return
 end
 
+"""
+    nonlinear_model(backend::AbstractAutomaticDifferentiation)
+
+Return a new nonlinear model appropriate for the given AD `backend`.
+
+The default returns `Model()`. Custom AD backends can override this
+to return their own model type.
+"""
+nonlinear_model(::AbstractAutomaticDifferentiation) = Model()
+
 """
     add_expression(model::Model, expr)::ExpressionIndex