DiscreteFactor multiply method

gtsam/discrete/DecisionTreeFactor.cpp

@@ -62,6 +62,18 @@ namespace gtsam {
     return error(values.discrete());
   }
 
+  /* ************************************************************************ */
+  DiscreteFactor::shared_ptr DecisionTreeFactor::multiply(
+      const DiscreteFactor::shared_ptr& f) const {
+    DiscreteFactor::shared_ptr result;
+    if (auto tf = std::dynamic_pointer_cast<TableFactor>(f)) {
+      result = std::make_shared<TableFactor>((*tf) * TableFactor(*this));
+    } else if (auto dtf = std::dynamic_pointer_cast<DecisionTreeFactor>(f)) {
+      result = std::make_shared<DecisionTreeFactor>(this->operator*(*dtf));
+    }
+    return result;
+  }
+
   /* ************************************************************************ */
   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

@@ -22,6 +22,7 @@
 #include <gtsam/discrete/DiscreteFactor.h>
 #include <gtsam/discrete/DiscreteKey.h>
 #include <gtsam/discrete/Ring.h>
+#include <gtsam/discrete/TableFactor.h>
 #include <gtsam/inference/Ordering.h>
 
 #include <algorithm>
@@ -147,6 +148,10 @@ namespace gtsam {
     /// Calculate error for DiscreteValues `x`, is -log(probability).
     double error(const DiscreteValues& values) const override;
 
+    /// Multiply factors, DiscreteFactor::shared_ptr edition
+    virtual DiscreteFactor::shared_ptr multiply(
+        const DiscreteFactor::shared_ptr& f) const override;
+
     /// multiply two factors
     DecisionTreeFactor operator*(const DecisionTreeFactor& f) const override {
       return apply(f, Ring::mul);

gtsam/discrete/DiscreteFactor.h

@@ -129,6 +129,16 @@ class GTSAM_EXPORT DiscreteFactor : public Factor {
   /// DecisionTreeFactor
   virtual DecisionTreeFactor operator*(const DecisionTreeFactor&) const = 0;
 
+  /**
+   * @brief Multiply in a DiscreteFactor and return the result as
+   * DiscreteFactor, both via shared pointers.
+   *
+   * @param df DiscreteFactor shared_ptr
+   * @return DiscreteFactor::shared_ptr
+   */
+  virtual DiscreteFactor::shared_ptr multiply(
+      const DiscreteFactor::shared_ptr& df) const = 0;
+
   virtual DecisionTreeFactor toDecisionTreeFactor() const = 0;
 
   /// @}

gtsam/discrete/DiscreteFactorGraph.cpp

@@ -65,11 +65,11 @@ namespace gtsam {
 
   /* ************************************************************************ */
   DecisionTreeFactor DiscreteFactorGraph::product() const {
-    DecisionTreeFactor result;
-    for (const sharedFactor& factor : *this) {
-      if (factor) result = (*factor) * result;
+    DiscreteFactor::shared_ptr result = *this->begin();
+    for (auto it = this->begin() + 1; it != this->end(); ++it) {
+      if (*it) result = result->multiply(*it);
     }
-    return result;
+    return result->toDecisionTreeFactor();
   }
 
   /* ************************************************************************ */

gtsam/discrete/TableFactor.cpp

@@ -254,6 +254,18 @@ DecisionTreeFactor TableFactor::operator*(const DecisionTreeFactor& f) const {
   return toDecisionTreeFactor() * f;
 }
 
+/* ************************************************************************ */
+DiscreteFactor::shared_ptr TableFactor::multiply(
+    const DiscreteFactor::shared_ptr& f) const {
+  DiscreteFactor::shared_ptr result;
+  if (auto tf = std::dynamic_pointer_cast<TableFactor>(f)) {
+    result = std::make_shared<TableFactor>(this->operator*(*tf));
+  } else if (auto dtf = std::dynamic_pointer_cast<DecisionTreeFactor>(f)) {
+    result = std::make_shared<TableFactor>(this->operator*(TableFactor(*dtf)));
+  }
+  return result;
+}
+
 /* ************************************************************************ */
 DecisionTreeFactor TableFactor::toDecisionTreeFactor() const {
   DiscreteKeys dkeys = discreteKeys();

gtsam/discrete/TableFactor.h

@@ -178,6 +178,10 @@ class GTSAM_EXPORT TableFactor : public DiscreteFactor {
   /// multiply with DecisionTreeFactor
   DecisionTreeFactor operator*(const DecisionTreeFactor& f) const override;
 
+  /// Multiply factors, DiscreteFactor::shared_ptr edition
+  virtual DiscreteFactor::shared_ptr multiply(
+      const DiscreteFactor::shared_ptr& f) const override;
+
   static double safe_div(const double& a, const double& b);
 
   /// divide by factor f (safely)