From: Luca Heltai <luca.heltai@sissa.it>
Date: Mon, 11 Apr 2016 07:46:43 +0000 (+0200)
Subject: Improved comment on periodicity for SphericalManifold.
X-Git-Tag: v8.5.0-rc1~1116^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F2411%2Fhead;p=dealii.git

Improved comment on periodicity for SphericalManifold.
---

diff --git a/source/grid/manifold_lib.cc b/source/grid/manifold_lib.cc
index dd95f0a80c..4031bd58f1 100644
--- a/source/grid/manifold_lib.cc
+++ b/source/grid/manifold_lib.cc
@@ -36,8 +36,11 @@ Tensor<1,spacedim>
 SphericalManifold<dim,spacedim>::get_periodicity()
 {
   Tensor<1,spacedim> periodicity;
-  // In two dimensions, theta is periodic. In three dimensions the variable
-  // that is periodic is phi. We have no periodicity in theta in 3d.
+  // In two dimensions, theta is periodic.
+  // In three dimensions things are a little more complicated, since the only variable
+  // that is truly periodic is phi, while theta should be bounded between
+  // 0 and pi. There is currently no way to enforce this, so here we only fix
+  // periodicity for the last variable, corresponding to theta in 2d and phi in 3d.
   periodicity[spacedim-1] = 2*numbers::PI;
   return periodicity;
 }