diff --git a/src/one-body-sample.org b/src/one-body-sample.org
index f8d3ef95681cc9025a82d3654936f0b7176c9ab3..eb399673eff07dd6a7680f833480910cd389417e 100644
--- a/src/one-body-sample.org
+++ b/src/one-body-sample.org
@@ -405,6 +405,7 @@
         (multigridStep, parset.get<size_t>("solver.tnnmg.maxiterations"),
          parset.get<double>("solver.tolerance"), &energyNorm, verbosity,
          false); // absolute error
+        overallSolver.preprocess();
         overallSolver.solve();
       };