From 09ddd433a60f4c89286202d08ade957bbd06269b Mon Sep 17 00:00:00 2001
From: Varun Agrawal <varagrawal@gmail.com>
Date: Fri, 10 Jul 2020 21:51:36 -0400
Subject: [PATCH] added note about code source and eigen resize for both static
 and dynamic matrices

---
 gtsam/base/Matrix.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/gtsam/base/Matrix.h b/gtsam/base/Matrix.h
index b1c6268a7..37ae1dd9a 100644
--- a/gtsam/base/Matrix.h
+++ b/gtsam/base/Matrix.h
@@ -548,6 +548,20 @@ GTSAM_EXPORT Vector columnNormSquare(const Matrix &A);
 namespace boost {
   namespace serialization {
 
+    /**
+     * Ref. https://stackoverflow.com/questions/18382457/eigen-and-boostserialize/22903063#22903063
+     * 
+     * Eigen supports calling resize() on both static and dynamic matrices.
+     * This allows for a uniform API, with resize having no effect if the static matrix
+     * is already the correct size.
+     * https://eigen.tuxfamily.org/dox/group__TutorialMatrixClass.html#TutorialMatrixSizesResizing
+     * 
+     * We use all the Matrix template parameters to ensure wide compatibility.
+     * 
+     * eigen_typekit in ROS uses the same code
+     * http://docs.ros.org/lunar/api/eigen_typekit/html/eigen__mqueue_8cpp_source.html
+     */
+
     // split version - sends sizes ahead
     template<class Archive,
              typename Scalar_,