diff --git a/dune/tectonic/myconvexproblem.hh b/dune/tectonic/myconvexproblem.hh
index 38b726be9628c97a0fc896103278e8362cb26223..c2142dace0cc592df4ca1267c5ec7c6c91bda933 100644
--- a/dune/tectonic/myconvexproblem.hh
+++ b/dune/tectonic/myconvexproblem.hh
@@ -23,15 +23,13 @@ class MyConvexProblem {
   */
   MyConvexProblem(MatrixType const &A,
                   Dune::GlobalNonlinearity<block_size> const &phi,
-                  VectorType const &f, VectorType &u)
-      : A(A), phi(phi), f(f), u(u) {};
+                  VectorType const &f)
+      : A(A), phi(phi), f(f) {};
 
   MatrixType const &A;
   Dune::GlobalNonlinearity<block_size> const &phi;
 
   VectorType const &f;
-
-  VectorType &u;
 };
 
 #endif
diff --git a/src/one-body-sample.cc b/src/one-body-sample.cc
index 96ff6b4330e9a927737272f169ed05f88bdbe74f..18705856c822ddf74b2b10b8415c42660d971e31 100644
--- a/src/one-body-sample.cc
+++ b/src/one-body-sample.cc
@@ -333,7 +333,7 @@ int main(int argc, char *argv[]) {
 
       if (parset.get<bool>("solver.nonlineargs.use")) {
         MyConvexProblemType myConvexProblem(stiffnessMatrix,
-                                            *myGlobalNonlinearity, b1, u1_diff);
+                                            *myGlobalNonlinearity, b1);
         MyBlockProblemType myBlockProblem(parset, myConvexProblem);
         nonlinearGSStep.setProblem(u1_diff, myBlockProblem);
 
@@ -348,7 +348,7 @@ int main(int argc, char *argv[]) {
 
       if (parset.get<bool>("solver.tnnmg.use")) {
         MyConvexProblemType myConvexProblem(stiffnessMatrix,
-                                            *myGlobalNonlinearity, b4, u4_diff);
+                                            *myGlobalNonlinearity, b4);
 
         MyBlockProblemType myBlockProblem(parset, myConvexProblem);
         multigridStep.setProblem(u4_diff, myBlockProblem);