Add .perpendicular() function in Geometry module (adapted from Eigen1)

Documentation:
 * add an overview for each module.
 * add an example for .all() and Cwise::operator<

1 files changed, 1 insertions, 1 deletions

diff --git a/Eigen/Geometry b/Eigen/Geometry
index 5e73ce992..1d8fb33ca 100644
--- a/Eigen/Geometry
+++ b/Eigen/Geometry
@@ -5,7 +5,7 @@
 
 namespace Eigen {
 
-/** \defgroup Geometry
+/** \defgroup Geometry Geometry module
   * This module provides support for:
   *  - fixed-size homogeneous transformations
   *  - 2D and 3D rotations