func_sq.hpp

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#ifndef MLPACK_CORE_OPTIMIZERS_FW_FUNC_SQ_HPP
#define MLPACK_CORE_OPTIMIZERS_FW_FUNC_SQ_HPP

#include <mlpack/prereqs.hpp>

namespace mlpack {
namespace optimization {

class FuncSq
{
 public:
  FuncSq(const arma::mat& A, const arma::vec& b) : A(A), b(b)
  {/* Nothing to do. */}

  double Evaluate(const arma::mat& coords)
  {
    arma::vec r = A * coords - b;
    return arma::dot(r, r) * 0.5;
  }

  void Gradient(const arma::mat& coords, arma::mat& gradient)
  {
    arma::vec r = A * coords - b;
    gradient = A.t() * r;
  }

  arma::mat MatrixA() const {return A;}
  arma::mat& MatrixA() {return A;}

  arma::vec Vectorb() const { return b; }
  arma::vec& Vectorb() { return b; }

 private:
  arma::mat A;

  arma::vec b;
};

} // namespace optimization
} // namespace mlpack

#endif