From 3b3e39381712d69f3252a27af6fa0da65acec68b Mon Sep 17 00:00:00 2001
From: Frank Dellaert <dellaert@gmail.com>
Date: Sun, 30 Dec 2018 18:37:38 -0500
Subject: [PATCH] Add serialization functions that call base classes, to avoid
 "unregistered void cast" errors (in MATLAB, as flagged by issue #398), as
 mentioned in
 http://tb-nguyen.blogspot.com/2009/08/more-on-using-boost-serialization-and.html

---
 gtsam/nonlinear/ExpressionFactor.h | 7 +++++++
 gtsam/sam/BearingFactor.h          | 8 ++++++++
 gtsam/sam/BearingRangeFactor.h     | 8 ++++++++
 gtsam/sam/RangeFactor.h            | 8 ++++++++
 4 files changed, 31 insertions(+)

diff --git a/gtsam/nonlinear/ExpressionFactor.h b/gtsam/nonlinear/ExpressionFactor.h
index 34ba8e1ff..04d82fe9a 100644
--- a/gtsam/nonlinear/ExpressionFactor.h
+++ b/gtsam/nonlinear/ExpressionFactor.h
@@ -266,6 +266,13 @@ class ExpressionFactor2 : public ExpressionFactor<T> {
   virtual Expression<T> expression() const {
     return expression(this->keys_[0], this->keys_[1]);
   }
+
+  friend class boost::serialization::access;
+  template <class ARCHIVE>
+  void serialize(ARCHIVE& ar, const unsigned int /*version*/) {
+    ar& boost::serialization::make_nvp(
+        "ExpressionFactor", boost::serialization::base_object<ExpressionFactor<T> >(*this));
+  }
 };
 // ExpressionFactor2
 
diff --git a/gtsam/sam/BearingFactor.h b/gtsam/sam/BearingFactor.h
index f190e683c..a9ed5ef4b 100644
--- a/gtsam/sam/BearingFactor.h
+++ b/gtsam/sam/BearingFactor.h
@@ -60,6 +60,14 @@ struct BearingFactor : public ExpressionFactor2<T, A1, A2> {
     std::cout << s << "BearingFactor" << std::endl;
     Base::print(s, kf);
   }
+
+ private:
+  friend class boost::serialization::access;
+  template <class ARCHIVE>
+  void serialize(ARCHIVE& ar, const unsigned int /*version*/) {
+    ar& boost::serialization::make_nvp(
+        "Base", boost::serialization::base_object<Base>(*this));
+  }
 };  // BearingFactor
 
 /// traits
diff --git a/gtsam/sam/BearingRangeFactor.h b/gtsam/sam/BearingRangeFactor.h
index 2dd1fecb8..44740f8ff 100644
--- a/gtsam/sam/BearingRangeFactor.h
+++ b/gtsam/sam/BearingRangeFactor.h
@@ -73,6 +73,14 @@ class BearingRangeFactor
     Base::print(s, kf);
   }
 
+
+ private:
+  friend class boost::serialization::access;
+  template <class ARCHIVE>
+  void serialize(ARCHIVE& ar, const unsigned int /*version*/) {
+    ar& boost::serialization::make_nvp(
+        "Base", boost::serialization::base_object<Base>(*this));
+  }
 };  // BearingRangeFactor
 
 /// traits
diff --git a/gtsam/sam/RangeFactor.h b/gtsam/sam/RangeFactor.h
index a5bcac822..40a9cf758 100644
--- a/gtsam/sam/RangeFactor.h
+++ b/gtsam/sam/RangeFactor.h
@@ -65,6 +65,14 @@ class RangeFactor : public ExpressionFactor2<T, A1, A2> {
     std::cout << s << "RangeFactor" << std::endl;
     Base::print(s, kf);
   }
+
+ private:
+  friend class boost::serialization::access;
+  template <class ARCHIVE>
+  void serialize(ARCHIVE& ar, const unsigned int /*version*/) {
+    ar& boost::serialization::make_nvp(
+        "Base", boost::serialization::base_object<Base>(*this));
+  }
 };  // \ RangeFactor
 
 /// traits