Fixed issues with sample

gtsam/discrete/DiscreteConditional.cpp

@@ -282,6 +282,15 @@ size_t DiscreteConditional::sample(size_t parent_value) const {
   return sample(values);
 }
 
+/* ******************************************************************************** */
+size_t DiscreteConditional::sample() const {
+  if (nrParents() != 0)
+    throw std::invalid_argument(
+        "sample() can only be invoked on no-parent prior");
+  DiscreteValues values;
+  return sample(values);
+}
+
 /* ************************************************************************* */
 std::string DiscreteConditional::markdown(const KeyFormatter& keyFormatter,
                                           const Names& names) const {

gtsam/discrete/DiscreteConditional.h

@@ -162,9 +162,12 @@ public:
   size_t sample(const DiscreteValues& parentsValues) const;
 
 
-  /// Single value version.
+  /// Single parent version.
   size_t sample(size_t parent_value) const;
 
+  /// Zero parent version.
+  size_t sample() const;
+
   /// @}
   /// @name Advanced Interface
   /// @{

gtsam/discrete/DiscretePrior.h

@@ -98,7 +98,7 @@ class GTSAM_EXPORT DiscretePrior : public DiscreteConditional {
    * sample
    * @return sample from conditional
    */
-  size_t sample() const { return Base::sample(DiscreteValues()); }
+  size_t sample() const { return Base::sample(); }
 
   /// @}
 };

gtsam/discrete/discrete.i

@@ -86,6 +86,7 @@ virtual class DiscreteConditional : gtsam::DecisionTreeFactor {
   size_t solve(const gtsam::DiscreteValues& parentsValues) const;
   size_t sample(const gtsam::DiscreteValues& parentsValues) const;
   size_t sample(size_t value) const;
+  size_t sample() const;
   void solveInPlace(gtsam::DiscreteValues @parentsValues) const;
   void sampleInPlace(gtsam::DiscreteValues @parentsValues) const;
   string markdown(const gtsam::KeyFormatter& keyFormatter =
@@ -105,7 +106,6 @@ virtual class DiscretePrior : gtsam::DiscreteConditional {
   double operator()(size_t value) const;
   std::vector<double> pmf() const;
   size_t solve() const;
-  size_t sample() const;
 };
 
 #include <gtsam/discrete/DiscreteBayesNet.h>

gtsam/discrete/tests/testDiscretePrior.cpp

@@ -28,6 +28,8 @@ static const DiscreteKey X(0, 2);
 /* ************************************************************************* */
 TEST(DiscretePrior, constructors) {
   DiscretePrior actual(X % "2/3");
+  EXPECT_LONGS_EQUAL(1, actual.nrFrontals());
+  EXPECT_LONGS_EQUAL(0, actual.nrParents());
   DecisionTreeFactor f(X, "0.4 0.6");
   DiscretePrior expected(f);
   EXPECT(assert_equal(expected, actual, 1e-9));
@@ -41,12 +43,18 @@ TEST(DiscretePrior, operator) {
 }
 
 /* ************************************************************************* */
-TEST(DiscretePrior, to_vector) {
+TEST(DiscretePrior, pmf) {
   DiscretePrior prior(X % "2/3");
   vector<double> expected {0.4, 0.6};
   EXPECT(prior.pmf() ==  expected);
 }
 
+/* ************************************************************************* */
+TEST(DiscretePrior, sample) {
+  DiscretePrior prior(X % "2/3");
+  prior.sample();
+}
+
 /* ************************************************************************* */
 int main() {
   TestResult tr;