From cbcfab4176b0577cc62e3cb77c3522cba90e2015 Mon Sep 17 00:00:00 2001
From: Varun Agrawal <varagrawal@gmail.com>
Date: Fri, 3 Jan 2025 13:09:25 -0500
Subject: [PATCH 1/4] serialize functions for Eigen::SparseVector

---
 gtsam/base/MatrixSerialization.h | 40 ++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/gtsam/base/MatrixSerialization.h b/gtsam/base/MatrixSerialization.h
index 11b6a417a..43c97097d 100644
--- a/gtsam/base/MatrixSerialization.h
+++ b/gtsam/base/MatrixSerialization.h
@@ -24,6 +24,7 @@
 
 #include <gtsam/base/Matrix.h>
 
+#include <Eigen/Sparse>
 #include <boost/serialization/array.hpp>
 #include <boost/serialization/nvp.hpp>
 #include <boost/serialization/split_free.hpp>
@@ -87,6 +88,45 @@ void serialize(Archive& ar, gtsam::Matrix& m, const unsigned int version) {
   split_free(ar, m, version);
 }
 
+/******************************************************************************/
+/// Customized functions for serializing Eigen::SparseVector
+template <class Archive, typename _Scalar, int _Options, typename _Index>
+void save(Archive& ar, const Eigen::SparseVector<_Scalar, _Options, _Index>& m,
+          const unsigned int /*version*/) {
+  _Index size = m.size();
+
+  std::vector<std::pair<Eigen::Index, _Scalar>> data;
+  for (typename Eigen::SparseVector<_Scalar, _Options, _Index>::InnerIterator
+           it(m);
+       it; ++it)
+    data.push_back({it.index(), it.value()});
+
+  ar << BOOST_SERIALIZATION_NVP(size);
+  ar << BOOST_SERIALIZATION_NVP(data);
+}
+
+template <class Archive, typename _Scalar, int _Options, typename _Index>
+void load(Archive& ar, Eigen::SparseVector<_Scalar, _Options, _Index>& m,
+          const unsigned int /*version*/) {
+  _Index size;
+  ar >> BOOST_SERIALIZATION_NVP(size);
+  m.resize(size);
+
+  std::vector<std::pair<Eigen::Index, _Scalar>> data;
+  ar >> BOOST_SERIALIZATION_NVP(data);
+
+  for (auto&& d : data) {
+    m.coeffRef(d.first) = d.second;
+  }
+}
+
+template <class Archive, typename _Scalar, int _Options, typename _Index>
+void serialize(Archive& ar, Eigen::SparseVector<_Scalar, _Options, _Index>& m,
+               const unsigned int version) {
+  split_free(ar, m, version);
+}
+/******************************************************************************/
+
 }  // namespace serialization
 }  // namespace boost
 #endif

From 5c4194e7cd800c8cd232f92a63dbd8e10b935340 Mon Sep 17 00:00:00 2001
From: Varun Agrawal <varagrawal@gmail.com>
Date: Fri, 3 Jan 2025 13:13:51 -0500
Subject: [PATCH 2/4] add serialization code to TableFactor

---
 gtsam/discrete/TableFactor.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/gtsam/discrete/TableFactor.h b/gtsam/discrete/TableFactor.h
index 5ddb4ab43..a2fdb4d32 100644
--- a/gtsam/discrete/TableFactor.h
+++ b/gtsam/discrete/TableFactor.h
@@ -31,6 +31,12 @@
 #include <utility>
 #include <vector>
 
+#if GTSAM_ENABLE_BOOST_SERIALIZATION
+#include <gtsam/base/MatrixSerialization.h>
+
+#include <boost/serialization/nvp.hpp>
+#endif
+
 namespace gtsam {
 
 class DiscreteConditional;
@@ -342,6 +348,19 @@ class GTSAM_EXPORT TableFactor : public DiscreteFactor {
   double error(const HybridValues& values) const override;
 
   /// @}
+
+ private:
+#if GTSAM_ENABLE_BOOST_SERIALIZATION
+  /** Serialization function */
+  friend class boost::serialization::access;
+  template <class ARCHIVE>
+  void serialize(ARCHIVE& ar, const unsigned int /*version*/) {
+    ar& BOOST_SERIALIZATION_BASE_OBJECT_NVP(Base);
+    ar& BOOST_SERIALIZATION_NVP(sparse_table_);
+    ar& BOOST_SERIALIZATION_NVP(denominators_);
+    ar& BOOST_SERIALIZATION_NVP(sorted_dkeys_);
+  }
+#endif
 };
 
 // traits

From ef2843c5b213e11463de8217e790a3e6e9cbbd25 Mon Sep 17 00:00:00 2001
From: Varun Agrawal <varagrawal@gmail.com>
Date: Fri, 3 Jan 2025 13:14:07 -0500
Subject: [PATCH 3/4] test for TableFactor serialization

---
 .../discrete/tests/testSerializationDiscrete.cpp  | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/gtsam/discrete/tests/testSerializationDiscrete.cpp b/gtsam/discrete/tests/testSerializationDiscrete.cpp
index df7df0b7e..9d15d0536 100644
--- a/gtsam/discrete/tests/testSerializationDiscrete.cpp
+++ b/gtsam/discrete/tests/testSerializationDiscrete.cpp
@@ -20,6 +20,7 @@
 #include <gtsam/base/serializationTestHelpers.h>
 #include <gtsam/discrete/DecisionTreeFactor.h>
 #include <gtsam/discrete/DiscreteDistribution.h>
+#include <gtsam/discrete/TableFactor.h>
 #include <gtsam/inference/Symbol.h>
 
 using namespace std;
@@ -32,6 +33,7 @@ BOOST_CLASS_EXPORT_GUID(Tree::Leaf, "gtsam_DecisionTreeStringInt_Leaf")
 BOOST_CLASS_EXPORT_GUID(Tree::Choice, "gtsam_DecisionTreeStringInt_Choice")
 
 BOOST_CLASS_EXPORT_GUID(DecisionTreeFactor, "gtsam_DecisionTreeFactor");
+BOOST_CLASS_EXPORT_GUID(TableFactor, "gtsam_TableFactor");
 
 using ADT = AlgebraicDecisionTree<Key>;
 BOOST_CLASS_EXPORT_GUID(ADT, "gtsam_AlgebraicDecisionTree");
@@ -79,6 +81,19 @@ TEST(DiscreteSerialization, DecisionTreeFactor) {
   EXPECT(equalsBinary<DecisionTreeFactor>(f));
 }
 
+/* ************************************************************************* */
+// Check serialization for TableFactor
+TEST(DiscreteSerialization, TableFactor) {
+  using namespace serializationTestHelpers;
+
+  DiscreteKey A(Symbol('x', 1), 3);
+  TableFactor tf(A % "1/2/2");
+
+  EXPECT(equalsObj<TableFactor>(tf));
+  EXPECT(equalsXML<TableFactor>(tf));
+  EXPECT(equalsBinary<TableFactor>(tf));
+}
+
 /* ************************************************************************* */
 // Check serialization for DiscreteConditional & DiscreteDistribution
 TEST(DiscreteSerialization, DiscreteConditional) {

From 3718cb19edd21c718fe280c712a793031b6fd707 Mon Sep 17 00:00:00 2001
From: Varun Agrawal <varagrawal@gmail.com>
Date: Fri, 3 Jan 2025 13:35:13 -0500
Subject: [PATCH 4/4] use string based constructor

---
 gtsam/discrete/tests/testSerializationDiscrete.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gtsam/discrete/tests/testSerializationDiscrete.cpp b/gtsam/discrete/tests/testSerializationDiscrete.cpp
index 9d15d0536..b118a00f6 100644
--- a/gtsam/discrete/tests/testSerializationDiscrete.cpp
+++ b/gtsam/discrete/tests/testSerializationDiscrete.cpp
@@ -87,7 +87,7 @@ TEST(DiscreteSerialization, TableFactor) {
   using namespace serializationTestHelpers;
 
   DiscreteKey A(Symbol('x', 1), 3);
-  TableFactor tf(A % "1/2/2");
+  TableFactor tf(A, "1 2 2");
 
   EXPECT(equalsObj<TableFactor>(tf));
   EXPECT(equalsXML<TableFactor>(tf));