add a cmake flag for easy toggling BetweenFactor jacobian computations

cmake/HandleGeneralOptions.cmake

@@ -28,6 +28,7 @@ option(GTSAM_INSTALL_MATLAB_TOOLBOX      "Enable/Disable installation of matlab
 option(GTSAM_ALLOW_DEPRECATED_SINCE_V41     "Allow use of methods/functions deprecated in GTSAM 4.1" ON)
 option(GTSAM_SUPPORT_NESTED_DISSECTION      "Support Metis-based nested dissection" ON)
 option(GTSAM_TANGENT_PREINTEGRATION         "Use new ImuFactor with integration on tangent space" ON)
+option(GTSAM_SLOW_BUT_CORRECT_BETWEENFACTOR "Use the slower but correct version of BetweenFactor" OFF)
 if(NOT MSVC AND NOT XCODE_VERSION)
     option(GTSAM_BUILD_WITH_CCACHE           "Use ccache compiler cache" ON)
 endif()

gtsam/config.h.in

@@ -77,3 +77,6 @@
 
 // Support Metis-based nested dissection
 #cmakedefine GTSAM_TANGENT_PREINTEGRATION
+
+// Toggle switch for BetweenFactor jacobian computation
+#cmakedefine GTSAM_SLOW_BUT_CORRECT_BETWEENFACTOR

gtsam/slam/BetweenFactor.h

@@ -103,7 +103,7 @@ namespace gtsam {
       boost::none, boost::optional<Matrix&> H2 = boost::none) const override {
       T hx = traits<T>::Between(p1, p2, H1, H2); // h(x)
       // manifold equivalent of h(x)-z -> log(z,h(x))
-#ifdef SLOW_BUT_CORRECT_BETWEENFACTOR
+#ifdef GTSAM_SLOW_BUT_CORRECT_BETWEENFACTOR
       typename traits<T>::ChartJacobian::Jacobian Hlocal;
       Vector rval = traits<T>::Local(measured_, hx, boost::none, (H1 || H2) ? &Hlocal : 0);
       if (H1) *H1 = Hlocal * (*H1);