From: Rene Gassmoeller <rene.gassmoeller@mailbox.org>
Date: Wed, 15 Nov 2017 21:10:51 +0000 (-0700)
Subject: Fix search for a vertex location
X-Git-Tag: v9.0.0-rc1~771^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F5472%2Fhead;p=dealii.git

Fix search for a vertex location
---

diff --git a/source/grid/grid_tools.cc b/source/grid/grid_tools.cc
index 4531701324..72f3f61284 100644
--- a/source/grid/grid_tools.cc
+++ b/source/grid/grid_tools.cc
@@ -1623,7 +1623,10 @@ next_cell:
             vertex_to_point = p - mesh.get_vertices()[closest_vertex_index];
           }
 
-        vertex_to_point /= vertex_to_point.norm();
+        const double vertex_point_norm = vertex_to_point.norm();
+        if (vertex_point_norm > 0)
+          vertex_to_point /= vertex_point_norm;
+
         const unsigned int n_neighbor_cells = vertex_to_cells[closest_vertex_index].size();
 
         // Create a corresponding map of vectors from vertex to cell center