From: David Wells <wellsd2@rpi.edu>
Date: Sun, 28 Aug 2016 18:38:55 +0000 (-0400)
Subject: Fix get_intermediate_point in 1D.
X-Git-Tag: v8.5.0-rc1~726^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a5d01559bdaab1d8a47fa379f513fd29ab0db174;p=dealii.git

Fix get_intermediate_point in 1D.

Since geometrical entities with spacedim == 1 are line segments, we
should just do a linear combination to find the intermediate
point (there is no need for angle calculations).
---

diff --git a/source/grid/manifold_lib.cc b/source/grid/manifold_lib.cc
index 69ace8735f..0b0fd94ae0 100644
--- a/source/grid/manifold_lib.cc
+++ b/source/grid/manifold_lib.cc
@@ -185,6 +185,11 @@ get_intermediate_point (const Point<spacedim> &p1,
   else if (w > 1.0 - tol)
     return p2;
 
+  // If the points are one dimensional then there is no need for anything but
+  // a linear combination.
+  if (spacedim == 1)
+    return Point<spacedim>(w*p2 + (1-w)*p1);
+
   const Tensor<1,spacedim> v1 = p1 - center;
   const Tensor<1,spacedim> v2 = p2 - center;
   const double r1 = v1.norm();