relative_distance_cost.h

/*
 * Copyright (c) 2020, The Regents of the University of California (Regents).
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 *    2. Redistributions in binary form must reproduce the above
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * Please contact the author(s) of this library if you have any questions.
 * Authors: David Fridovich-Keil   ( dfk@eecs.berkeley.edu )
 */

///////////////////////////////////////////////////////////////////////////////
//
// Distance between two state positions.
//
///////////////////////////////////////////////////////////////////////////////

#ifndef ILQGAMES_COST_RELATIVE_DISTANCE_COST_H
#define ILQGAMES_COST_RELATIVE_DISTANCE_COST_H

#include <ilqgames/cost/time_invariant_cost.h>
#include <ilqgames/utils/types.h>

#include <glog/logging.h>
#include <string>
#include <utility>

namespace ilqgames {

class RelativeDistanceCost : public TimeInvariantCost {
 public:
  // Construct from a multiplicative weight and the dimensions in which to apply
  // the quadratic difference cost.
  RelativeDistanceCost(float weight,
                       const std::pair<Dimension, Dimension>& dims1,
                       const std::pair<Dimension, Dimension>& dims2,
                       const std::string& name = "")
      : TimeInvariantCost(weight, name), dims1_(dims1), dims2_(dims2) {}

  // Evaluate this cost at the current input.
  float Evaluate(const VectorXf& input) const;

  // Quadraticize this cost at the given input, and add to the running=
  // sum of gradients and Hessians (if non-null).
  void Quadraticize(const VectorXf& input, MatrixXf* hess,
                    VectorXf* grad) const;

 private:
  // Sets of dimensions whose pairwise differences will constitute the cost.
  const std::pair<Dimension, Dimension> dims1_, dims2_;
};  //\class RelativeDistanceCost

}  // namespace ilqgames

#endif