#ifndef DISCRETE_SLICE_SAMPLER_H_
#define DISCRETE_SLICE_SAMPLER_H_

#include <sampler/Slicer.h>

class StochasticNode;

/**
 * @short Discrete slice sampler
 *
 * Slice sampler for discrete valued distributions.
 *
 * To sample a discrete valued random variable X, we create an
 * auxiliary variable Y which is real valued, and for which p_[Y](y) =
 * p_[X](floor(y)).  Hence Y has a piecewise-constant density function
 * on the real line.  We sample Y and then set X = floor(Y).
 */
class DiscreteSliceSampler : public Slicer {
  double _x;
 public:
  /**
   * Constructor for Slice Sampler
   * @param node Node to sample
   * @param graph Graph within which sampling takes place
   * @param width Initial width of slice
   * @param maxwidth Maximal width of slice as a multiple of the width
   * parameter
   * @param nburn Length of burnin
   */
  DiscreteSliceSampler(StochasticNode *node, Graph const &graph,
		       double width=2, long ndoubles = 10);
  void setValue(double x);
  double value();
  static bool canSample(StochasticNode const *node, Graph const &graph);
  double lowerLimit();
  double upperLimit();
  void update();
};

#endif /* DISCRETE_SLICE_SAMPLER_H_ */