Add no-argument solve and sample to DiscretePrior

gtsam/discrete/DiscretePrior.h

@@ -81,9 +81,25 @@ class GTSAM_EXPORT DiscretePrior : public DiscreteConditional {
   /// Evaluate given a single value.
   double operator()(size_t value) const;
 
-  /// Evaluate given a single value.
+  /// We also want to keep the Base version, taking DiscreteValues:
+  // TODO(dellaert): does not play well with wrapper!
+  // using Base::operator();
+
+  /// Return entire probability mass function.
   std::vector<double> pmf() const;
 
+  /**
+   * solve a conditional
+   * @return MPE value of the child (1 frontal variable).
+   */
+  size_t solve() const { return Base::solve({}); }
+
+  /**
+   * sample
+   * @return sample from conditional
+   */
+  size_t sample() const { return Base::sample({}); }
+
   /// @}
 };
 // DiscretePrior

gtsam/discrete/discrete.i

@@ -81,6 +81,8 @@ virtual class DiscretePrior : gtsam::DiscreteConditional {
                  gtsam::DefaultKeyFormatter) const;
   double operator()(size_t value) const;
   std::vector<double> pmf() const;
+  size_t solve() const;
+  size_t sample() const;
 };
 
 #include <gtsam/discrete/DiscreteBayesNet.h>