quadratic.hpp

// BSD 3-Clause License
//
// Copyright (C) 2019-2025, LAAS-CNRS, University of Edinburgh,
//                          Heriot-Watt University
// Copyright note valid unless otherwise stated in individual files.
// All rights reserved.
 
#ifndef CROCODDYL_CORE_ACTIVATIONS_QUADRATIC_HPP_
#define CROCODDYL_CORE_ACTIVATIONS_QUADRATIC_HPP_
 
#include "crocoddyl/core/activation-base.hpp"
#include "crocoddyl/core/fwd.hpp"
 
namespace crocoddyl {
 
template <typename _Scalar>
class ActivationModelQuadTpl : public ActivationModelAbstractTpl<_Scalar> {
 public:
  EIGEN_MAKE_ALIGNED_OPERATOR_NEW
  CROCODDYL_DERIVED_CAST(ActivationModelBase, ActivationModelQuadTpl)
 
  typedef _Scalar Scalar;
  typedef MathBaseTpl<Scalar> MathBase;
  typedef ActivationModelAbstractTpl<Scalar> Base;
  typedef ActivationDataAbstractTpl<Scalar> ActivationDataAbstract;
  typedef typename MathBase::VectorXs VectorXs;
  typedef typename MathBase::MatrixXs MatrixXs;
 
  explicit ActivationModelQuadTpl(const std::size_t nr) : Base(nr) {};
  virtual ~ActivationModelQuadTpl() = default;
 
  virtual void calc(const std::shared_ptr<ActivationDataAbstract>& data,
                    const Eigen::Ref<const VectorXs>& r) override {
    if (static_cast<std::size_t>(r.size()) != nr_) {
      throw_pretty(
          "Invalid argument: " << "r has wrong dimension (it should be " +
                                      std::to_string(nr_) + ")");
    }
    data->a_value = Scalar(0.5) * r.dot(r);
  };
 
  virtual void calcDiff(const std::shared_ptr<ActivationDataAbstract>& data,
                        const Eigen::Ref<const VectorXs>& r) override {
    if (static_cast<std::size_t>(r.size()) != nr_) {
      throw_pretty(
          "Invalid argument: " << "r has wrong dimension (it should be " +
                                      std::to_string(nr_) + ")");
    }
 
    data->Ar = r;
    // The Hessian has constant values which were set in createData.
    assert_pretty(MatrixXs(data->Arr).isApprox(MatrixXs::Identity(nr_, nr_)),
                  "Arr has wrong value");
  };
 
  virtual std::shared_ptr<ActivationDataAbstract> createData() override {
    std::shared_ptr<ActivationDataAbstract> data =
        std::allocate_shared<ActivationDataAbstract>(
            Eigen::aligned_allocator<ActivationDataAbstract>(), this);
    data->Arr.diagonal().setOnes();
    return data;
  };
 
  template <typename NewScalar>
  ActivationModelQuadTpl<NewScalar> cast() const {
    typedef ActivationModelQuadTpl<NewScalar> ReturnType;
    ReturnType res(nr_);
    return res;
  }
 
  virtual void print(std::ostream& os) const override {
    os << "ActivationModelQuad {nr=" << nr_ << "}";
  }
 
 protected:
  using Base::nr_;
};
 
}  // namespace crocoddyl
 
CROCODDYL_DECLARE_EXTERN_TEMPLATE_CLASS(crocoddyl::ActivationModelQuadTpl)
 
#endif  // CROCODDYL_CORE_ACTIVATIONS_QUADRATIC_HPP_