From 9c9e23858ee763381e56d1924253207a88ffb9c6 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Tue, 30 Aug 2016 11:10:08 +0200
Subject: Doc: split customizing-eigen page into sub-pages and re-structure a
 bit the different topics

---
 doc/CustomizingEigen_InheritingMatrix.dox | 34 +++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 doc/CustomizingEigen_InheritingMatrix.dox

(limited to 'doc/CustomizingEigen_InheritingMatrix.dox')

diff --git a/doc/CustomizingEigen_InheritingMatrix.dox b/doc/CustomizingEigen_InheritingMatrix.dox
new file mode 100644
index 000000000..b21e55433
--- /dev/null
+++ b/doc/CustomizingEigen_InheritingMatrix.dox
@@ -0,0 +1,34 @@
+namespace Eigen {
+
+/** \page TopicCustomizing_InheritingMatrix Inheriting from Matrix
+
+Before inheriting from Matrix, be really, I mean REALLY, sure that using
+EIGEN_MATRIX_PLUGIN is not what you really want (see previous section).
+If you just need to add few members to Matrix, this is the way to go.
+
+An example of when you actually need to inherit Matrix, is when you
+have several layers of heritage such as 
+MyVerySpecificVector1, MyVerySpecificVector2 -> MyVector1 -> Matrix and
+MyVerySpecificVector3, MyVerySpecificVector4 -> MyVector2 -> Matrix.
+
+In order for your object to work within the %Eigen framework, you need to
+define a few members in your inherited class.
+
+Here is a minimalistic example:
+
+\include CustomizingEigen_Inheritance.cpp
+
+Output: \verbinclude CustomizingEigen_Inheritance.out
+
+This is the kind of error you can get if you don't provide those methods
+\verbatim
+error: no match for ‘operator=’ in ‘v = Eigen::operator*(
+const Eigen::MatrixBase<Eigen::Matrix<double, -0x000000001, 1, 0, -0x000000001, 1> >::Scalar&, 
+const Eigen::MatrixBase<Eigen::Matrix<double, -0x000000001, 1> >::StorageBaseType&)
+(((const Eigen::MatrixBase<Eigen::Matrix<double, -0x000000001, 1> >::StorageBaseType&)
+((const Eigen::MatrixBase<Eigen::Matrix<double, -0x000000001, 1> >::StorageBaseType*)(& v))))’
+\endverbatim
+
+*/
+
+}
-- 
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