From 26b4c0422d11480d43b72ed659a52f01235426c4 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Mon, 30 Oct 2017 16:32:59 -0600
Subject: [PATCH] Make things work with complex-valued vectors.

---
 include/deal.II/numerics/vector_tools.templates.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/deal.II/numerics/vector_tools.templates.h b/include/deal.II/numerics/vector_tools.templates.h
index 3694ce4be2..54cff879a5 100644
--- a/include/deal.II/numerics/vector_tools.templates.h
+++ b/include/deal.II/numerics/vector_tools.templates.h
@@ -7265,9 +7265,10 @@ namespace VectorTools
               for (unsigned int q=0; q<n_q_points; ++q)
                 {
                   // compute (f.n) n
-                  const Number f_dot_n
-                    = (data.psi_grads[q][k] * fe_values.normal_vector(q));
-                  const Tensor<1,spacedim,Number> f_dot_n_times_n (f_dot_n * fe_values.normal_vector(q));
+                  const typename ProductType<Number,double>::type f_dot_n
+                    = data.psi_grads[q][k] * fe_values.normal_vector(q);
+                  const Tensor<1,spacedim,Number> f_dot_n_times_n
+                    = f_dot_n * fe_values.normal_vector(q);
 
                   data.psi_grads[q][k] -= (data.function_grads[q][k] + f_dot_n_times_n);
                 }
-- 
2.39.5