From 3ad9c9494e64f02dd3d4779c8765c181178ce693 Mon Sep 17 00:00:00 2001
From: Yong-Dian Jian <ydjian@gmail.com>
Date: Tue, 23 Nov 2010 15:27:23 +0000
Subject: [PATCH] add interface to access block matrix

---
 gtsam/linear/GaussianFactor.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gtsam/linear/GaussianFactor.h b/gtsam/linear/GaussianFactor.h
index 87f46203e..682b758fd 100644
--- a/gtsam/linear/GaussianFactor.h
+++ b/gtsam/linear/GaussianFactor.h
@@ -151,6 +151,10 @@ namespace gtsam {
 
     ABlock getA(iterator variable) { return Ab_(variable - keys_.begin()); }
 
+    // direct indexing
+    constABlock getA(size_t idx) const { return Ab_(idx); }
+    ABlock getA(size_t idx) { return Ab_(idx); }
+
     /** Return the dimension of the variable pointed to by the given key iterator
      * todo: Remove this in favor of keeping track of dimensions with variables?
      */