From ba0b68110f5ae428574cc69554454f1b9476792b Mon Sep 17 00:00:00 2001
From: dellaert <dellaert@cc.gatech.edu>
Date: Mon, 13 Oct 2014 13:56:51 +0200
Subject: [PATCH] Boost Fusion needed to access values :-(

---
 .../nonlinear/tests/testExpressionFactor.cpp   | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/gtsam_unstable/nonlinear/tests/testExpressionFactor.cpp b/gtsam_unstable/nonlinear/tests/testExpressionFactor.cpp
index f3099778f..45936fc8e 100644
--- a/gtsam_unstable/nonlinear/tests/testExpressionFactor.cpp
+++ b/gtsam_unstable/nonlinear/tests/testExpressionFactor.cpp
@@ -462,10 +462,24 @@ typedef mpl::transform<MyTypes,Jacobian<Point2,MPL::_1> >::type Jacobians;
 BOOST_MPL_ASSERT((mpl::equal< ExpectedJacobians, Jacobians >));
 
 // Try accessing a Jacobian
-typedef mpl::int_<1> one;
-typedef mpl::at<Jacobians,one>::type Jacobian23; // base zero !
+typedef mpl::at_c<Jacobians,1>::type Jacobian23; // base zero !
 BOOST_MPL_ASSERT((boost::is_same< Matrix23, Jacobian23>));
 
+#include <boost/fusion/adapted/mpl.hpp>
+#include <boost/fusion/include/mpl.hpp>
+#include <boost/fusion/include/at_c.hpp>
+
+// Create a value and access it
+TEST(ExpressionFactor, JacobiansValue) {
+  Matrix23 expected;
+  ExpectedJacobians jacobians;
+  using boost::fusion::at_c;
+
+  Matrix23 actual = at_c<1>(jacobians);
+  CHECK(actual.cols() == expected.cols());
+  CHECK(actual.rows() == expected.rows());
+}
+
 /* ************************************************************************* */
 int main() {
   TestResult tr;