smooth-2norm.hpp

// BSD 3-Clause License
//
// Copyright (C) 2020-2025, LAAS-CNRS, Heriot-Watt University
// Copyright note valid unless otherwise stated in individual files.
// All rights reserved.

#ifndef CROCODDYL_CORE_ACTIVATIONS_SMOOTH_2NORM_HPP_
#define CROCODDYL_CORE_ACTIVATIONS_SMOOTH_2NORM_HPP_

#include "crocoddyl/core/activation-base.hpp"
#include "crocoddyl/core/fwd.hpp"

namespace crocoddyl {

template <typename _Scalar>
class ActivationModelSmooth2NormTpl
 : public ActivationModelAbstractTpl<_Scalar> {
 public:
 EIGEN_MAKE_ALIGNED_OPERATOR_NEW
 CROCODDYL_DERIVED_CAST(ActivationModelBase, ActivationModelSmooth2NormTpl)

 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 ActivationModelSmooth2NormTpl(const std::size_t nr,
 const Scalar eps = Scalar(1.))
 : Base(nr), eps_(eps) {
 if (eps < Scalar(0.)) {
 throw_pretty("Invalid argument: " << "eps should be a positive value");
 }
 };
 virtual ~ActivationModelSmooth2NormTpl() = 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_) + ")");
 }
 using std::sqrt;
 data->a_value = sqrt(r.squaredNorm() + eps_);
 };

 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 / data->a_value;
 data->Arr.diagonal().array() = Scalar(1) / pow(data->a_value, Scalar(3));
 };

 virtual std::shared_ptr<ActivationDataAbstract> createData() override {
 return std::allocate_shared<ActivationDataAbstract>(
 Eigen::aligned_allocator<ActivationDataAbstract>(), this);
 };

 template <typename NewScalar>
 ActivationModelSmooth2NormTpl<NewScalar> cast() const {
 typedef ActivationModelSmooth2NormTpl<NewScalar> ReturnType;
 ReturnType res(nr_, scalar_cast<NewScalar>(eps_));
 return res;
 }

 protected:
 virtual void print(std::ostream& os) const override {
 os << "ActivationModelSmooth2Norm {nr=" << nr_ << ", eps=" << eps_ << "}";
 }

 using Base::nr_;
 Scalar eps_;
};

} // namespace crocoddyl

CROCODDYL_DECLARE_EXTERN_TEMPLATE_CLASS(
 crocoddyl::ActivationModelSmooth2NormTpl)

#endif // CROCODDYL_CORE_ACTIVATIONS_SMOOTH_2NORM_HPP_