TableFactor Improvements

gtsam/discrete/DecisionTreeFactor.cpp

@@ -33,16 +33,13 @@ namespace gtsam {
 
   /* ************************************************************************ */
   DecisionTreeFactor::DecisionTreeFactor(const DiscreteKeys& keys,
-                                        const ADT& potentials)
-      : DiscreteFactor(keys.indices()),
-        ADT(potentials),
-        cardinalities_(keys.cardinalities()) {}
+                                         const ADT& potentials)
+      : DiscreteFactor(keys.indices(), keys.cardinalities()), ADT(potentials) {}
 
   /* ************************************************************************ */
   DecisionTreeFactor::DecisionTreeFactor(const DiscreteConditional& c)
-      : DiscreteFactor(c.keys()),
-        AlgebraicDecisionTree<Key>(c),
-        cardinalities_(c.cardinalities_) {}
+      : DiscreteFactor(c.keys(), c.cardinalities()),
+        AlgebraicDecisionTree<Key>(c) {}
 
   /* ************************************************************************ */
   bool DecisionTreeFactor::equals(const DiscreteFactor& other,
@@ -182,15 +179,12 @@ namespace gtsam {
   }
 
   /* ************************************************************************ */
-  DiscreteKeys DecisionTreeFactor::discreteKeys() const {
-    DiscreteKeys result;
-    for (auto&& key : keys()) {
-      DiscreteKey dkey(key, cardinality(key));
-      if (std::find(result.begin(), result.end(), dkey) == result.end()) {
-        result.push_back(dkey);
-      }
+  std::vector<double> DecisionTreeFactor::probabilities() const {
+    std::vector<double> probs;
+    for (auto&& [key, value] : enumerate()) {
+      probs.push_back(value);
     }
-    return result;
+    return probs;
   }
 
   /* ************************************************************************ */
@@ -288,29 +282,26 @@ namespace gtsam {
 
   /* ************************************************************************ */
   DecisionTreeFactor::DecisionTreeFactor(const DiscreteKeys& keys,
-                                        const vector<double>& table)
-      : DiscreteFactor(keys.indices()),
-        AlgebraicDecisionTree<Key>(keys, table),
-        cardinalities_(keys.cardinalities()) {}
+                                         const vector<double>& table)
+      : DiscreteFactor(keys.indices(), keys.cardinalities()),
+        AlgebraicDecisionTree<Key>(keys, table) {}
 
   /* ************************************************************************ */
   DecisionTreeFactor::DecisionTreeFactor(const DiscreteKeys& keys,
-                                        const string& table)
-      : DiscreteFactor(keys.indices()),
-        AlgebraicDecisionTree<Key>(keys, table),
-        cardinalities_(keys.cardinalities()) {}
+                                         const string& table)
+      : DiscreteFactor(keys.indices(), keys.cardinalities()),
+        AlgebraicDecisionTree<Key>(keys, table) {}
 
   /* ************************************************************************ */
   DecisionTreeFactor DecisionTreeFactor::prune(size_t maxNrAssignments) const {
     const size_t N = maxNrAssignments;
 
     // Get the probabilities in the decision tree so we can threshold.
     std::vector<double> probabilities;
-    this->visitLeaf([&](const Leaf& leaf) {
-      size_t nrAssignments = leaf.nrAssignments();
-      double prob = leaf.constant();
-      probabilities.insert(probabilities.end(), nrAssignments, prob);
-    });
+    // NOTE(Varun) this is potentially slow due to the cartesian product
+    for (auto&& [assignment, prob] : this->enumerate()) {
+      probabilities.push_back(prob);
+    }
 
     // The number of probabilities can be lower than max_leaves
     if (probabilities.size() <= N) {

gtsam/discrete/DecisionTreeFactor.h

@@ -50,10 +50,6 @@ namespace gtsam {
     typedef std::shared_ptr<DecisionTreeFactor> shared_ptr;
     typedef AlgebraicDecisionTree<Key> ADT;
 
-   protected:
-    std::map<Key, size_t> cardinalities_;
-
-   public:
     /// @name Standard Constructors
     /// @{
 
@@ -119,8 +115,6 @@ namespace gtsam {
 
     static double safe_div(const double& a, const double& b);
 
-    size_t cardinality(Key j) const { return cardinalities_.at(j); }
-
     /// divide by factor f (safely)
     DecisionTreeFactor operator/(const DecisionTreeFactor& f) const {
       return apply(f, safe_div);
@@ -179,8 +173,8 @@ namespace gtsam {
     /// Enumerate all values into a map from values to double.
     std::vector<std::pair<DiscreteValues, double>> enumerate() const;
 
-    /// Return all the discrete keys associated with this factor.
-    DiscreteKeys discreteKeys() const;
+    /// Get all the probabilities in order of assignment values
+    std::vector<double> probabilities() const;
 
     /**
      * @brief Prune the decision tree of discrete variables.
@@ -260,7 +254,6 @@ namespace gtsam {
     void serialize(ARCHIVE& ar, const unsigned int /*version*/) {
       ar& BOOST_SERIALIZATION_BASE_OBJECT_NVP(Base);
       ar& BOOST_SERIALIZATION_BASE_OBJECT_NVP(ADT);
-      ar& BOOST_SERIALIZATION_NVP(cardinalities_);
     }
 #endif
   };

gtsam/discrete/DiscreteFactor.cpp

@@ -28,6 +28,18 @@ using namespace std;
 
 namespace gtsam {
 
+/* ************************************************************************ */
+DiscreteKeys DiscreteFactor::discreteKeys() const {
+  DiscreteKeys result;
+  for (auto&& key : keys()) {
+    DiscreteKey dkey(key, cardinality(key));
+    if (std::find(result.begin(), result.end(), dkey) == result.end()) {
+      result.push_back(dkey);
+    }
+  }
+  return result;
+}
+
 /* ************************************************************************* */
 double DiscreteFactor::error(const DiscreteValues& values) const {
   return -std::log((*this)(values));

gtsam/discrete/DiscreteFactor.h

@@ -36,28 +36,35 @@ class HybridValues;
  * @ingroup discrete
  */
 class GTSAM_EXPORT DiscreteFactor: public Factor {
-
-public:
-
+ public:
   // typedefs needed to play nice with gtsam
-  typedef DiscreteFactor This; ///< This class
-  typedef std::shared_ptr<DiscreteFactor> shared_ptr; ///< shared_ptr to this class
-  typedef Factor Base; ///< Our base class
+  typedef DiscreteFactor This;  ///< This class
+  typedef std::shared_ptr<DiscreteFactor>
+      shared_ptr;       ///< shared_ptr to this class
+  typedef Factor Base;  ///< Our base class
 
-  using Values = DiscreteValues; ///< backwards compatibility
+  using Values = DiscreteValues;  ///< backwards compatibility
 
-public:
+ protected:
+  /// Map of Keys and their cardinalities.
+  std::map<Key, size_t> cardinalities_;
 
+ public:
   /// @name Standard Constructors
   /// @{
 
   /** Default constructor creates empty factor */
   DiscreteFactor() {}
 
-  /** Construct from container of keys.  This constructor is used internally from derived factor
-   *  constructors, either from a container of keys or from a boost::assign::list_of. */
-  template<typename CONTAINER>
-  DiscreteFactor(const CONTAINER& keys) : Base(keys) {}
+  /**
+   * Construct from container of keys and map of cardinalities.
+   * This constructor is used internally from derived factor constructors,
+   * either from a container of keys or from a boost::assign::list_of.
+   */
+  template <typename CONTAINER>
+  DiscreteFactor(const CONTAINER& keys,
+                 const std::map<Key, size_t> cardinalities = {})
+      : Base(keys), cardinalities_(cardinalities) {}
 
   /// @}
   /// @name Testable
@@ -77,6 +84,13 @@ class GTSAM_EXPORT DiscreteFactor: public Factor {
   /// @name Standard Interface
   /// @{
 
+  /// Return all the discrete keys associated with this factor.
+  DiscreteKeys discreteKeys() const;
+
+  std::map<Key, size_t> cardinalities() const { return cardinalities_; }
+
+  size_t cardinality(Key j) const { return cardinalities_.at(j); }
+
   /// Find value for given assignment of values to variables
   virtual double operator()(const DiscreteValues&) const = 0;
 
@@ -124,6 +138,17 @@ class GTSAM_EXPORT DiscreteFactor: public Factor {
       const Names& names = {}) const = 0;
 
   /// @}
+
+ private:
+#ifdef 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(cardinalities_);
+  }
+#endif
 };
 // DiscreteFactor
 

gtsam/discrete/TableFactor.cpp

@@ -13,11 +13,12 @@
  * @file TableFactor.cpp
  * @brief discrete factor
  * @date May 4, 2023
- * @author Yoonwoo Kim
+ * @author Yoonwoo Kim, Varun Agrawal
  */
 
 #include <gtsam/base/FastSet.h>
 #include <gtsam/discrete/DecisionTreeFactor.h>
+#include <gtsam/discrete/DiscreteConditional.h>
 #include <gtsam/discrete/TableFactor.h>
 #include <gtsam/hybrid/HybridValues.h>
 
@@ -33,8 +34,7 @@ TableFactor::TableFactor() {}
 /* ************************************************************************ */
 TableFactor::TableFactor(const DiscreteKeys& dkeys,
                          const TableFactor& potentials)
-    : DiscreteFactor(dkeys.indices()),
-      cardinalities_(potentials.cardinalities_) {
+    : DiscreteFactor(dkeys.indices(), dkeys.cardinalities()) {
   sparse_table_ = potentials.sparse_table_;
   denominators_ = potentials.denominators_;
   sorted_dkeys_ = discreteKeys();
@@ -44,18 +44,22 @@ TableFactor::TableFactor(const DiscreteKeys& dkeys,
 /* ************************************************************************ */
 TableFactor::TableFactor(const DiscreteKeys& dkeys,
                          const Eigen::SparseVector<double>& table)
-    : DiscreteFactor(dkeys.indices()), sparse_table_(table.size()) {
+    : DiscreteFactor(dkeys.indices(), dkeys.cardinalities()),
+      sparse_table_(table.size()) {
   sparse_table_ = table;
   double denom = table.size();
   for (const DiscreteKey& dkey : dkeys) {
-    cardinalities_.insert(dkey);
     denom /= dkey.second;
     denominators_.insert(std::pair<Key, double>(dkey.first, denom));
   }
   sorted_dkeys_ = discreteKeys();
   sort(sorted_dkeys_.begin(), sorted_dkeys_.end());
 }
 
+/* ************************************************************************ */
+TableFactor::TableFactor(const DiscreteConditional& c)
+    : TableFactor(c.discreteKeys(), c.probabilities()) {}
+
 /* ************************************************************************ */
 Eigen::SparseVector<double> TableFactor::Convert(
     const std::vector<double>& table) {
@@ -435,18 +439,6 @@ std::vector<std::pair<DiscreteValues, double>> TableFactor::enumerate() const {
   return result;
 }
 
-/* ************************************************************************ */
-DiscreteKeys TableFactor::discreteKeys() const {
-  DiscreteKeys result;
-  for (auto&& key : keys()) {
-    DiscreteKey dkey(key, cardinality(key));
-    if (std::find(result.begin(), result.end(), dkey) == result.end()) {
-      result.push_back(dkey);
-    }
-  }
-  return result;
-}
-
 // Print out header.
 /* ************************************************************************ */
 string TableFactor::markdown(const KeyFormatter& keyFormatter,

gtsam/discrete/TableFactor.h

@@ -12,7 +12,7 @@
 /**
  * @file TableFactor.h
  * @date May 4, 2023
- * @author Yoonwoo Kim
+ * @author Yoonwoo Kim, Varun Agrawal
  */
 
 #pragma once
@@ -32,6 +32,7 @@
 
 namespace gtsam {
 
+class DiscreteConditional;
 class HybridValues;
 
 /**
@@ -44,8 +45,6 @@ class HybridValues;
  */
 class GTSAM_EXPORT TableFactor : public DiscreteFactor {
  protected:
-  /// Map of Keys and their cardinalities.
-  std::map<Key, size_t> cardinalities_;
   /// SparseVector of nonzero probabilities.
   Eigen::SparseVector<double> sparse_table_;
 
@@ -57,10 +56,10 @@ class GTSAM_EXPORT TableFactor : public DiscreteFactor {
 
   /**
    * @brief Uses lazy cartesian product to find nth entry in the cartesian
-   * product of arrays in O(1) 
-   * Example) 
-   *   v0 | v1 | val 
-   *    0 |  0 |  10 
+   * product of arrays in O(1)
+   * Example)
+   *   v0 | v1 | val
+   *    0 |  0 |  10
    *    0 |  1 |  21
    *    1 |  0 |  32
    *    1 |  1 |  43
@@ -75,13 +74,13 @@ class GTSAM_EXPORT TableFactor : public DiscreteFactor {
    * @brief Return ith key in keys_ as a DiscreteKey
    * @param i ith key in keys_
    * @return DiscreteKey
-   * */ 
+   */
   DiscreteKey discreteKey(size_t i) const {
     return DiscreteKey(keys_[i], cardinalities_.at(keys_[i]));
   }
 
   /// Convert probability table given as doubles to SparseVector.
-  /// Example) {0, 1, 1, 0, 0, 1, 0} -> values: {1, 1, 1}, indices: {1, 2, 5} 
+  /// Example) {0, 1, 1, 0, 0, 1, 0} -> values: {1, 1, 1}, indices: {1, 2, 5}
   static Eigen::SparseVector<double> Convert(const std::vector<double>& table);
 
   /// Convert probability table given as string to SparseVector.
@@ -142,6 +141,9 @@ class GTSAM_EXPORT TableFactor : public DiscreteFactor {
   TableFactor(const DiscreteKey& key, const std::vector<double>& row)
       : TableFactor(DiscreteKeys{key}, row) {}
 
+  /** Construct from a DiscreteConditional type */
+  explicit TableFactor(const DiscreteConditional& c);
+
   /// @}
   /// @name Testable
   /// @{
@@ -180,8 +182,6 @@ class GTSAM_EXPORT TableFactor : public DiscreteFactor {
 
   static double safe_div(const double& a, const double& b);
 
-  size_t cardinality(Key j) const { return cardinalities_.at(j); }
-
   /// divide by factor f (safely)
   TableFactor operator/(const TableFactor& f) const {
     return apply(f, safe_div);
@@ -274,9 +274,6 @@ class GTSAM_EXPORT TableFactor : public DiscreteFactor {
   /// Enumerate all values into a map from values to double.
   std::vector<std::pair<DiscreteValues, double>> enumerate() const;
 
-  /// Return all the discrete keys associated with this factor.
-  DiscreteKeys discreteKeys() const;
-
   /**
    * @brief Prune the decision tree of discrete variables.
    *

gtsam/discrete/tests/testDecisionTreeFactor.cpp

@@ -51,6 +51,11 @@ TEST( DecisionTreeFactor, constructors)
 
   // Assert that error = -log(value)
   EXPECT_DOUBLES_EQUAL(-log(f1(values)), f1.error(values), 1e-9);
+
+  // Construct from DiscreteConditional
+  DiscreteConditional conditional(X | Y = "1/1 2/3 1/4");
+  DecisionTreeFactor f4(conditional);
+  EXPECT_DOUBLES_EQUAL(0.8, f4(values), 1e-9);
 }
 
 /* ************************************************************************* */