discrete error method that returns an ADT

gtsam/discrete/DecisionTreeFactor.cpp

@@ -62,6 +62,22 @@ namespace gtsam {
     return error(values.discrete());
   }
 
+  /* ************************************************************************ */
+  AlgebraicDecisionTree<Key> DecisionTreeFactor::error() const {
+    // Get all possible assignments
+    DiscreteKeys dkeys = discreteKeys();
+    // Reverse to make cartesian product output a more natural ordering.
+    DiscreteKeys rdkeys(dkeys.rbegin(), dkeys.rend());
+    const auto assignments = DiscreteValues::CartesianProduct(rdkeys);
+
+    // Construct vector with error values
+    std::vector<double> errors;
+    for (const auto& assignment : assignments) {
+      errors.push_back(error(assignment));
+    }
+    return AlgebraicDecisionTree<Key>(dkeys, errors);
+  }
+
   /* ************************************************************************ */
   double DecisionTreeFactor::safe_div(const double& a, const double& b) {
     // The use for safe_div is when we divide the product factor by the sum

gtsam/discrete/DecisionTreeFactor.h

@@ -292,6 +292,9 @@ namespace gtsam {
    */
   double error(const HybridValues& values) const override;
 
+  /// Compute error for each assignment and return as a tree
+  AlgebraicDecisionTree<Key> error() const override;
+
   /// @}
 
    private:

gtsam/discrete/DiscreteFactor.h

@@ -18,9 +18,10 @@
 
 #pragma once
 
+#include <gtsam/base/Testable.h>
+#include <gtsam/discrete/AlgebraicDecisionTree.h>
 #include <gtsam/discrete/DiscreteValues.h>
 #include <gtsam/inference/Factor.h>
-#include <gtsam/base/Testable.h>
 
 #include <string>
 namespace gtsam {
@@ -35,7 +36,7 @@ class HybridValues;
  *
  * @ingroup discrete
  */
-class GTSAM_EXPORT DiscreteFactor: public Factor {
+class GTSAM_EXPORT DiscreteFactor : public Factor {
  public:
   // typedefs needed to play nice with gtsam
   typedef DiscreteFactor This;  ///< This class
@@ -103,15 +104,19 @@ class GTSAM_EXPORT DiscreteFactor: public Factor {
    */
   double error(const HybridValues& c) const override;
 
-  /// Multiply in a DecisionTreeFactor and return the result as DecisionTreeFactor
+  /// Compute error for each assignment and return as a tree
+  virtual AlgebraicDecisionTree<Key> error() const = 0;
+
+  /// Multiply in a DecisionTreeFactor and return the result as
+  /// DecisionTreeFactor
   virtual DecisionTreeFactor operator*(const DecisionTreeFactor&) const = 0;
 
   virtual DecisionTreeFactor toDecisionTreeFactor() const = 0;
 
   /// @}
   /// @name Wrapper support
   /// @{
-  
+
   /// Translation table from values to strings.
   using Names = DiscreteValues::Names;
 
@@ -175,4 +180,4 @@ template<> struct traits<DiscreteFactor> : public Testable<DiscreteFactor> {};
 std::vector<double> expNormalize(const std::vector<double> &logProbs);
 
 
-}// namespace gtsam
+}  // namespace gtsam

gtsam/discrete/TableFactor.cpp

@@ -168,6 +168,11 @@ double TableFactor::error(const HybridValues& values) const {
   return error(values.discrete());
 }
 
+/* ************************************************************************ */
+AlgebraicDecisionTree<Key> TableFactor::error() const {
+  return toDecisionTreeFactor().error();
+}
+
 /* ************************************************************************ */
 DecisionTreeFactor TableFactor::operator*(const DecisionTreeFactor& f) const {
   return toDecisionTreeFactor() * f;

gtsam/discrete/TableFactor.h

@@ -358,6 +358,9 @@ class GTSAM_EXPORT TableFactor : public DiscreteFactor {
    */
   double error(const HybridValues& values) const override;
 
+  /// Compute error for each assignment and return as a tree
+  AlgebraicDecisionTree<Key> error() const override;
+
   /// @}
 };
 

gtsam/discrete/tests/testDecisionTreeFactor.cpp

@@ -67,6 +67,24 @@ TEST( DecisionTreeFactor, constructors)
   EXPECT_DOUBLES_EQUAL(0.8, f4(x121), 1e-9);
 }
 
+/* ************************************************************************* */
+TEST(DecisionTreeFactor, Error) {
+  // Declare a bunch of keys
+  DiscreteKey X(0,2), Y(1,3), Z(2,2);
+
+  // Create factors
+  DecisionTreeFactor f(X & Y & Z, "2 5 3 6 4 7 25 55 35 65 45 75");
+
+  auto errors = f.error();
+  // regression
+  AlgebraicDecisionTree<Key> expected(
+      {X, Y, Z},
+      vector<double>{-0.69314718, -1.6094379, -1.0986123, -1.7917595,
+                     -1.3862944, -1.9459101, -3.2188758, -4.0073332, -3.5553481,
+                     -4.1743873, -3.8066625, -4.3174881});
+  EXPECT(assert_equal(expected, errors, 1e-6));
+}
+
 /* ************************************************************************* */
 TEST(DecisionTreeFactor, multiplication) {
   DiscreteKey v0(0, 2), v1(1, 2), v2(2, 2);

gtsam_unstable/discrete/AllDiff.h

@@ -53,6 +53,11 @@ class GTSAM_UNSTABLE_EXPORT AllDiff : public Constraint {
   /// Multiply into a decisiontree
   DecisionTreeFactor operator*(const DecisionTreeFactor& f) const override;
 
+  /// Compute error for each assignment and return as a tree
+  AlgebraicDecisionTree<Key> error() const override {
+    throw std::runtime_error("AllDiff::error not implemented");
+  }
+
   /*
    * Ensure Arc-consistency by checking every possible value of domain j.
    * @param j domain to be checked

gtsam_unstable/discrete/BinaryAllDiff.h

@@ -91,6 +91,11 @@ class BinaryAllDiff : public Constraint {
       const Domains&) const override {
     throw std::runtime_error("BinaryAllDiff::partiallyApply not implemented");
   }
+
+  /// Compute error for each assignment and return as a tree
+  AlgebraicDecisionTree<Key> error() const override {
+    throw std::runtime_error("BinaryAllDiff::error not implemented");
+  }
 };
 
 }  // namespace gtsam

gtsam_unstable/discrete/Domain.h

@@ -69,6 +69,11 @@ class GTSAM_UNSTABLE_EXPORT Domain : public Constraint {
     }
   }
 
+  /// Compute error for each assignment and return as a tree
+  AlgebraicDecisionTree<Key> error() const override {
+    throw std::runtime_error("Domain::error not implemented");
+  }
+
   // Return concise string representation, mostly to debug arc consistency.
   // Converts from base 0 to base1.
   std::string base1Str() const;

gtsam_unstable/discrete/SingleValue.h

@@ -49,6 +49,11 @@ class GTSAM_UNSTABLE_EXPORT SingleValue : public Constraint {
     }
   }
 
+  /// Compute error for each assignment and return as a tree
+  AlgebraicDecisionTree<Key> error() const override {
+    throw std::runtime_error("SingleValue::error not implemented");
+  }
+
   /// Calculate value
   double operator()(const DiscreteValues& values) const override;