quadratic-barrier.hpp

// BSD 3-Clause License
//
// Copyright (C) 2019-2025, LAAS-CNRS, University of Edinburgh,
// University of Oxford, Heriot-Watt University
// Copyright note valid unless otherwise stated in individual files. All
// rights reserved.

#ifndef CROCODDYL_CORE_ACTIVATIONS_QUADRATIC_BARRIER_HPP_
#define CROCODDYL_CORE_ACTIVATIONS_QUADRATIC_BARRIER_HPP_

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

namespace crocoddyl {

template <typename _Scalar>
struct ActivationBoundsTpl {
 EIGEN_MAKE_ALIGNED_OPERATOR_NEW

 typedef _Scalar Scalar;
 typedef MathBaseTpl<Scalar> MathBase;
 typedef typename MathBase::VectorXs VectorXs;
 typedef typename MathBase::MatrixXs MatrixXs;

 ActivationBoundsTpl(const VectorXs& lower, const VectorXs& upper,
 const Scalar b = Scalar(1.))
 : lb(lower), ub(upper), beta(b) {
 if (lb.size() != ub.size()) {
 throw_pretty("Invalid argument: "
 << "The lower and upper bounds don't have the same "
 "dimension (lb,ub dimensions equal to " +
 std::to_string(lb.size()) + "," +
 std::to_string(ub.size()) + ", respectively)");
 }
 if (beta < Scalar(0) || beta > Scalar(1.)) {
 throw_pretty(
 "Invalid argument: " << "The range of beta is between 0 and 1");
 }
 for (std::size_t i = 0; i < static_cast<std::size_t>(lb.size()); ++i) {
 if (isfinite(lb(i)) && isfinite(ub(i))) {
 if (lb(i) - ub(i) > Scalar(0)) {
 throw_pretty("Invalid argument: "
 << "The lower and upper bounds are badly defined; ub "
 "has to be bigger / equals to lb");
 }
 }
 // Assign the maximum value for infinity/nan values
 if (!isfinite(lb(i))) {
 lb(i) = -std::numeric_limits<Scalar>::max();
 }
 if (!isfinite(ub(i))) {
 ub(i) = std::numeric_limits<Scalar>::max();
 }
 }

 if (beta >= Scalar(0) && beta <= Scalar(1.)) {
 for (std::size_t i = 0; i < static_cast<std::size_t>(lb.size()); ++i) {
 // do not use beta when one of the bounds is inf
 if (lb(i) != (-std::numeric_limits<Scalar>::max()) &&
 ub(i) != (std::numeric_limits<Scalar>::max())) {
 Scalar m = Scalar(0.5) * (lb(i) + ub(i));
 Scalar d = Scalar(0.5) * (ub(i) - lb(i));
 lb(i) = m - beta * d;
 ub(i) = m + beta * d;
 }
 }
 } else {
 beta = Scalar(1.);
 }
 }
 ActivationBoundsTpl(const ActivationBoundsTpl& other)
 : lb(other.lb), ub(other.ub), beta(other.beta) {}
 ActivationBoundsTpl() : beta(Scalar(1.)) {}

 template <typename NewScalar>
 ActivationBoundsTpl<NewScalar> cast() const {
 typedef ActivationBoundsTpl<NewScalar> ReturnType;
 ReturnType res(lb.template cast<NewScalar>(), ub.template cast<NewScalar>(),
 scalar_cast<NewScalar>(beta));
 return res;
 }

 ActivationBoundsTpl& operator=(const ActivationBoundsTpl& other) {
 if (this != &other) {
 lb = other.lb;
 ub = other.ub;
 beta = other.beta;
 }
 return *this;
 }

 friend std::ostream& operator<<(std::ostream& os,
 const ActivationBoundsTpl& bounds) {
 bounds.print(os);
 return os;
 }

 void print(std::ostream& os) const {
 os << "ActivationBounds {lb=" << lb.transpose() << ", ub=" << ub.transpose()
 << ", beta=" << beta << "}";
 }

 VectorXs lb;
 VectorXs ub;
 Scalar beta;
};

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

 typedef _Scalar Scalar;
 typedef MathBaseTpl<Scalar> MathBase;
 typedef ActivationModelAbstractTpl<Scalar> Base;
 typedef ActivationDataAbstractTpl<Scalar> ActivationDataAbstract;
 typedef ActivationDataQuadraticBarrierTpl<Scalar> Data;
 typedef ActivationBoundsTpl<Scalar> ActivationBounds;
 typedef typename MathBase::VectorXs VectorXs;
 typedef typename MathBase::MatrixXs MatrixXs;

 explicit ActivationModelQuadraticBarrierTpl(const ActivationBounds& bounds)
 : Base(bounds.lb.size()), bounds_(bounds) {};
 virtual ~ActivationModelQuadraticBarrierTpl() = 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_) + ")");
 }

 std::shared_ptr<Data> d = std::static_pointer_cast<Data>(data);

 d->rlb_min_ = (r - bounds_.lb).array().min(Scalar(0.));
 d->rub_max_ = (r - bounds_.ub).array().max(Scalar(0.));
 data->a_value = Scalar(0.5) * d->rlb_min_.matrix().squaredNorm() +
 Scalar(0.5) * d->rub_max_.matrix().squaredNorm();
 };

 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_) + ")");
 }

 std::shared_ptr<Data> d = std::static_pointer_cast<Data>(data);
 data->Ar = (d->rlb_min_ + d->rub_max_).matrix();

 using pinocchio::internal::if_then_else;
 for (Eigen::Index i = 0; i < data->Arr.cols(); i++) {
 data->Arr.diagonal()[i] = if_then_else(
 pinocchio::internal::LE, r[i] - bounds_.lb[i], Scalar(0.), Scalar(1.),
 if_then_else(pinocchio::internal::GE, r[i] - bounds_.ub[i],
 Scalar(0.), Scalar(1.), Scalar(0.)));
 }
 };

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

 template <typename NewScalar>
 ActivationModelQuadraticBarrierTpl<NewScalar> cast() const {
 typedef ActivationModelQuadraticBarrierTpl<NewScalar> ReturnType;
 ReturnType res(bounds_.template cast<NewScalar>());
 return res;
 }

 const ActivationBounds& get_bounds() const { return bounds_; };
 void set_bounds(const ActivationBounds& bounds) { bounds_ = bounds; };

 virtual void print(std::ostream& os) const override {
 os << "ActivationModelQuadraticBarrier {nr=" << nr_ << "}";
 }

 protected:
 using Base::nr_;

 private:
 ActivationBounds bounds_;
};

template <typename _Scalar>
struct ActivationDataQuadraticBarrierTpl
 : public ActivationDataAbstractTpl<_Scalar> {
 EIGEN_MAKE_ALIGNED_OPERATOR_NEW

 typedef _Scalar Scalar;
 typedef MathBaseTpl<Scalar> MathBase;
 typedef typename MathBase::ArrayXs ArrayXs;
 typedef typename MathBase::VectorXs VectorXs;
 typedef typename MathBase::DiagonalMatrixXs DiagonalMatrixXs;
 typedef ActivationDataAbstractTpl<Scalar> Base;

 template <typename Activation>
 explicit ActivationDataQuadraticBarrierTpl(Activation* const activation)
 : Base(activation),
 rlb_min_(activation->get_nr()),
 rub_max_(activation->get_nr()) {
 rlb_min_.setZero();
 rub_max_.setZero();
 }

 ArrayXs rlb_min_;
 ArrayXs rub_max_;

 using Base::a_value;
 using Base::Ar;
 using Base::Arr;
};

} // namespace crocoddyl

CROCODDYL_DECLARE_EXTERN_TEMPLATE_STRUCT(crocoddyl::ActivationBoundsTpl)
CROCODDYL_DECLARE_EXTERN_TEMPLATE_CLASS(
 crocoddyl::ActivationModelQuadraticBarrierTpl)
CROCODDYL_DECLARE_EXTERN_TEMPLATE_STRUCT(
 crocoddyl::ActivationDataQuadraticBarrierTpl)

#endif // CROCODDYL_CORE_ACTIVATIONS_QUADRATIC_BARRIER_HPP_