pop_front

cpp/BayesNet.h

@@ -64,6 +64,12 @@ namespace gtsam {
 			conditionals_.push_front(conditional);
 		}
 
+		/**
+		 * pop_front: remove node at the bottom, used in marginalization
+		 * For example P(ABC)=P(A|BC)P(B|C)P(C) becomes P(BC)=P(B|C)P(C)
+		 */
+		inline void pop_front() {conditionals_.pop_front();}
+
 		/** size is the number of nodes */
 		inline size_t size() const {
 			return conditionals_.size();

cpp/testSymbolicBayesNet.cpp

@@ -43,6 +43,29 @@ TEST( SymbolicBayesNet, constructor )
   CHECK(assert_equal(expected, *actual));
 }
 
+/* ************************************************************************* */
+TEST( SymbolicBayesNet, pop_front )
+{
+	SymbolicConditional::shared_ptr
+		A(new SymbolicConditional("A","B","C")),
+		B(new SymbolicConditional("B","C")),
+		C(new SymbolicConditional("C"));
+
+	// Expected after pop_front
+	SymbolicBayesNet expected;
+	expected.push_back(B);
+	expected.push_back(C);
+
+	// Actual
+	SymbolicBayesNet actual;
+	actual.push_back(A);
+	actual.push_back(B);
+	actual.push_back(C);
+	actual.pop_front();
+
+  CHECK(assert_equal(expected,actual));
+}
+
 /* ************************************************************************* */
 int main() {
 	TestResult tr;