Allow for comparison of minima

src/test-gradient-method.cc

@@ -11,7 +11,7 @@
 #include <cassert>
 
 template <int dim, class Function>
-void functionTester(
+double functionTester(
     Dune::SampleFunctional<dim, Function> J,
     typename Dune::SampleFunctional<dim, Function>::SmallVector &start,
     size_t runs) {
@@ -23,7 +23,9 @@ void functionTester(
     if (i != runs)
       std::cout << "New value: J(...) = " << J(start) << std::endl;
   }
-  std::cout << "Final value J(...) = " << J(start) << std::endl;
+  double const final = J(start);
+  std::cout << "Final value J(...) = " << final << std::endl;
+  return final;
 }
 
 void testSampleFunction() {