Fix uninitialised memory in test case

src/one-body-sample.cc

@@ -81,7 +81,7 @@ int main() {
     // Fill initial guess with other semi-random numbers
     for (size_t i = 0; i < f.size(); ++i)
       for (size_t j = 0; j < dim; ++j)
-        f[i][j] = i * j;
+        u[i][j] = 17 * j;
 
     Dune::BitSetVector<VectorType::block_type::dimension> ignoreNodes(
         grid.size(grid.maxLevel(), dim), false);