curvature_cost.h

/*
 * Copyright (c) 2019, The Regents of the University of California (Regents).
 * All rights reserved.
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 *       notice, this list of conditions and the following disclaimer.
 *
 *    2. Redistributions in binary form must reproduce the above
 *       copyright notice, this list of conditions and the following
 *       disclaimer in the documentation and/or other materials provided
 *       with the distribution.
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 *    3. Neither the name of the copyright holder nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * 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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 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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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 )
 */

///////////////////////////////////////////////////////////////////////////////
//
// Quadratic cost on curvature (angular speed / longitudinal speed)
//
///////////////////////////////////////////////////////////////////////////////

#ifndef ILQGAMES_COST_CURVATURE_COST_H
#define ILQGAMES_COST_CURVATURE_COST_H

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

#include <string>

namespace ilqgames {

class CurvatureCost : public TimeInvariantCost {
 public:
  CurvatureCost(float weight, Dimension omega_idx, Dimension v_idx,
                const std::string& name = "")
      : TimeInvariantCost(weight, name), omega_idx_(omega_idx), v_idx_(v_idx) {}

  // 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.
  void Quadraticize(const VectorXf& input, MatrixXf* hess,
                    VectorXf* grad) const;

 private:
  // Compute curvature.
  float Curvature(const VectorXf& input) const {
    return input(omega_idx_) / input(v_idx_);
  }

  // Dimensions of omega (angular speed) and v (longitudinal speed).
  Dimension omega_idx_;
  Dimension v_idx_;
};  //\class CurvatureCost

}  // namespace ilqgames

#endif