Interpolator.h

#pragma once

#include <vector>
#include <fstream>

namespace rl {
/** A multi-dimensional data point */
struct Wire {
  std::vector<double> action;
  double reward;
};

/** An interpolator of multi-dimensional data points */
class Interpolator {
public:

  /** Initializes the parameters of an interpolator from a file. Returns false if the interpolator stored in the file is not the correct type */
  virtual bool initFromStream(std::ifstream *in) = 0;

  /** Stores the parameters of an interpolator in a file */
  virtual void store(std::ofstream *out) = 0;

  /** Uses the interpolator function to compute the reward of an action vector given a set of control wires */
  virtual double getReward(const std::vector<Wire> &controlWires, const std::vector<double> &action) = 0;

  /** The partial derivative of the interpolator function with respect to the reward of a control wire */
  virtual double rewardDerivative(const std::vector<double> &action, const Wire &wire, const std::vector<Wire> &controlWires) = 0;

  /** The partial derivative of the interpolator function with respect to the value of one term of the action vector of a control wire */
  virtual double actionTermDerivative(double actionTerm, double wireActionTerm, const std::vector<double> &action, const Wire &wire, const std::vector<Wire> &controlWires) = 0;

  /** Gets an interpolator from a file. Tries out every interpolator and throws an error none of the interpolators successfully read from the file */
  static Interpolator * getAnyInterpolatorFromFile(std::ifstream *in);
};
}