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|---|---|---|---|
| 1 | /////////////////////////////////////////////////////////////////////////////// | ||
| 2 | // BSD 3-Clause License | ||
| 3 | // | ||
| 4 | // Copyright (C) 2020-2025, LAAS-CNRS, Heriot-Watt University | ||
| 5 | // Copyright note valid unless otherwise stated in individual files. | ||
| 6 | // All rights reserved. | ||
| 7 | /////////////////////////////////////////////////////////////////////////////// | ||
| 8 | |||
| 9 | #ifndef CROCODDYL_CORE_ACTIVATIONS_SMOOTH_2NORM_HPP_ | ||
| 10 | #define CROCODDYL_CORE_ACTIVATIONS_SMOOTH_2NORM_HPP_ | ||
| 11 | |||
| 12 | #include "crocoddyl/core/activation-base.hpp" | ||
| 13 | #include "crocoddyl/core/fwd.hpp" | ||
| 14 | |||
| 15 | namespace crocoddyl { | ||
| 16 | |||
| 17 | /** | ||
| 18 | * @brief Smooth-2Norm activation | ||
| 19 | * | ||
| 20 | * This activation function describes a smooth representation of a 2-norm of a | ||
| 21 | * residual vector, i.e. \f[ \begin{equation} \sqrt{\epsilon + sum^nr_{i=0} | ||
| 22 | * \|r_i\|^2} \end{equation} \f] where \f$\epsilon\f$ defines the smoothing | ||
| 23 | * factor, \f$r_i\f$ is the scalar residual for the \f$i\f$ constraints, | ||
| 24 | * \f$nr\f$ is the dimension of the residual vector. | ||
| 25 | * | ||
| 26 | * The computation of the function and it derivatives are carried out in | ||
| 27 | * `calc()` and `caldDiff()`, respectively. | ||
| 28 | * | ||
| 29 | * \sa `calc()`, `calcDiff()`, `createData()` | ||
| 30 | */ | ||
| 31 | template <typename _Scalar> | ||
| 32 | class ActivationModelSmooth2NormTpl | ||
| 33 | : public ActivationModelAbstractTpl<_Scalar> { | ||
| 34 | public: | ||
| 35 | EIGEN_MAKE_ALIGNED_OPERATOR_NEW | ||
| 36 | ✗ | CROCODDYL_DERIVED_CAST(ActivationModelBase, ActivationModelSmooth2NormTpl) | |
| 37 | |||
| 38 | typedef _Scalar Scalar; | ||
| 39 | typedef MathBaseTpl<Scalar> MathBase; | ||
| 40 | typedef ActivationModelAbstractTpl<Scalar> Base; | ||
| 41 | typedef ActivationDataAbstractTpl<Scalar> ActivationDataAbstract; | ||
| 42 | typedef typename MathBase::VectorXs VectorXs; | ||
| 43 | typedef typename MathBase::MatrixXs MatrixXs; | ||
| 44 | |||
| 45 | /** | ||
| 46 | * @brief Initialize the smooth-2Norm activation model | ||
| 47 | * | ||
| 48 | * The default `eps` value is defined as 1. | ||
| 49 | * | ||
| 50 | * @param[in] nr Dimension of the residual vector | ||
| 51 | * @param[in] eps Smoothing factor (default: 1.) | ||
| 52 | */ | ||
| 53 | ✗ | explicit ActivationModelSmooth2NormTpl(const std::size_t nr, | |
| 54 | const Scalar eps = Scalar(1.)) | ||
| 55 | ✗ | : Base(nr), eps_(eps) { | |
| 56 | ✗ | if (eps < Scalar(0.)) { | |
| 57 | ✗ | throw_pretty("Invalid argument: " << "eps should be a positive value"); | |
| 58 | } | ||
| 59 | ✗ | }; | |
| 60 | ✗ | virtual ~ActivationModelSmooth2NormTpl() = default; | |
| 61 | |||
| 62 | /** | ||
| 63 | * @brief Compute the smooth-2Norm function | ||
| 64 | * | ||
| 65 | * @param[in] data Smooth-2Norm activation data | ||
| 66 | * @param[in] r Residual vector \f$\mathbf{r}\in\mathbb{R}^{nr}\f$ | ||
| 67 | */ | ||
| 68 | ✗ | virtual void calc(const std::shared_ptr<ActivationDataAbstract>& data, | |
| 69 | const Eigen::Ref<const VectorXs>& r) override { | ||
| 70 | ✗ | if (static_cast<std::size_t>(r.size()) != nr_) { | |
| 71 | ✗ | throw_pretty( | |
| 72 | "Invalid argument: " << "r has wrong dimension (it should be " + | ||
| 73 | std::to_string(nr_) + ")"); | ||
| 74 | } | ||
| 75 | using std::sqrt; | ||
| 76 | ✗ | data->a_value = sqrt(r.squaredNorm() + eps_); | |
| 77 | ✗ | }; | |
| 78 | |||
| 79 | /** | ||
| 80 | * @brief Compute the derivatives of the smooth-2Norm function | ||
| 81 | * | ||
| 82 | * @param[in] data Smooth-2Norm activation data | ||
| 83 | * @param[in] r Residual vector \f$\mathbf{r}\in\mathbb{R}^{nr}\f$ | ||
| 84 | */ | ||
| 85 | ✗ | virtual void calcDiff(const std::shared_ptr<ActivationDataAbstract>& data, | |
| 86 | const Eigen::Ref<const VectorXs>& r) override { | ||
| 87 | ✗ | if (static_cast<std::size_t>(r.size()) != nr_) { | |
| 88 | ✗ | throw_pretty( | |
| 89 | "Invalid argument: " << "r has wrong dimension (it should be " + | ||
| 90 | std::to_string(nr_) + ")"); | ||
| 91 | } | ||
| 92 | |||
| 93 | ✗ | data->Ar = r / data->a_value; | |
| 94 | ✗ | data->Arr.diagonal().array() = Scalar(1) / pow(data->a_value, Scalar(3)); | |
| 95 | ✗ | }; | |
| 96 | |||
| 97 | /** | ||
| 98 | * @brief Create the smooth-2norm activation data | ||
| 99 | * | ||
| 100 | * @return the activation data | ||
| 101 | */ | ||
| 102 | ✗ | virtual std::shared_ptr<ActivationDataAbstract> createData() override { | |
| 103 | return std::allocate_shared<ActivationDataAbstract>( | ||
| 104 | ✗ | Eigen::aligned_allocator<ActivationDataAbstract>(), this); | |
| 105 | }; | ||
| 106 | |||
| 107 | template <typename NewScalar> | ||
| 108 | ✗ | ActivationModelSmooth2NormTpl<NewScalar> cast() const { | |
| 109 | typedef ActivationModelSmooth2NormTpl<NewScalar> ReturnType; | ||
| 110 | ✗ | ReturnType res(nr_, scalar_cast<NewScalar>(eps_)); | |
| 111 | ✗ | return res; | |
| 112 | } | ||
| 113 | |||
| 114 | protected: | ||
| 115 | /** | ||
| 116 | * @brief Print relevant information of the smooth-1norm model | ||
| 117 | * | ||
| 118 | * @param[out] os Output stream object | ||
| 119 | */ | ||
| 120 | ✗ | virtual void print(std::ostream& os) const override { | |
| 121 | ✗ | os << "ActivationModelSmooth2Norm {nr=" << nr_ << ", eps=" << eps_ << "}"; | |
| 122 | ✗ | } | |
| 123 | |||
| 124 | using Base::nr_; //!< Dimension of the residual vector | ||
| 125 | Scalar eps_; //!< Smoothing factor | ||
| 126 | }; | ||
| 127 | |||
| 128 | } // namespace crocoddyl | ||
| 129 | |||
| 130 | CROCODDYL_DECLARE_EXTERN_TEMPLATE_CLASS( | ||
| 131 | crocoddyl::ActivationModelSmooth2NormTpl) | ||
| 132 | |||
| 133 | #endif // CROCODDYL_CORE_ACTIVATIONS_SMOOTH_2NORM_HPP_ | ||
| 134 |