diff --git a/src/test-gradient-method.cc b/src/test-gradient-method.cc
index 97fc79928b9c210622aaa86707d3913c0cc6323f..33597685ea9e1559a64b783b50b0820190d85dec 100644
--- a/src/test-gradient-method.cc
+++ b/src/test-gradient-method.cc
@@ -35,7 +35,7 @@ void testIdentity() {
   b[0] = 1;
   b[1] = 2;
 
-  Dune::Identity f;
+  Dune::LinearFunction f(1);
   Functional J(A, b, Dune::MyNonlinearity<dim>(f));
 
   Functional::SmallVector start = b;