BarrierForms.hpp

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#pragma once
 
#include <polyfem/Common.hpp>
#include <polyfem/solver/forms/SmoothContactForm.hpp>
#include <polyfem/utils/BoundarySampler.hpp>
#include <polyfem/optimization/DiffCache.hpp>
#include <polyfem/optimization/forms/ParametrizationForm.hpp>
#include <polyfem/optimization/var2sims/VariableToSimulationGroup.hpp>
 
#include <Eigen/Core>
#include <ipc/potentials/barrier_potential.hpp>
#include <ipc/smooth_contact/smooth_collisions.hpp>
#include <ipc/smooth_contact/smooth_contact_potential.hpp>
 
#include <memory>
#include <map>
#include <set>
#include <string>
#include <vector>
 
namespace polyfem::solver
{
    class CollisionBarrierForm : public AdjointForm
    {
    public:
        CollisionBarrierForm(const VariableToSimulationGroup &variable_to_simulation, std::shared_ptr<const varform::DifferentiableVarForm> varform, const io::ResourceIO &resources, const double dhat, const double dmin = 0);
 
        double value_unweighted(const Eigen::VectorXd &x) const override;
 
        void compute_partial_gradient(const Eigen::VectorXd &x, Eigen::VectorXd &gradv) const override;
 
        void solution_changed(const Eigen::VectorXd &x) override;
 
        bool is_step_collision_free(const Eigen::VectorXd &x0, const Eigen::VectorXd &x1) const override;
 
        std::string name() const override { return "collision barrier"; }
 
        double max_step_size(const Eigen::VectorXd &x0, const Eigen::VectorXd &x1) const override;
 
    protected:
        void build_collision_set(const Eigen::MatrixXd &displaced_surface);
 
        Eigen::VectorXd get_updated_mesh_nodes(const Eigen::VectorXd &x) const;
 
        std::shared_ptr<const varform::DifferentiableVarForm> varform_;
 
        Eigen::VectorXd X_init;
 
        ipc::CollisionMesh collision_mesh_;
        ipc::NormalCollisions collision_set;
        const double dhat_;
        const double dmin_;
        ipc::BroadPhaseMethod broad_phase_method_;
 
        ipc::BarrierPotential barrier_potential_;
    };
 
    class LayerThicknessForm : public CollisionBarrierForm
    {
    public:
        LayerThicknessForm(const VariableToSimulationGroup &variable_to_simulations,
                           std::shared_ptr<const varform::DifferentiableVarForm> varform,
                           const io::ResourceIO &resources,
                           const std::vector<int> &boundary_ids,
                           const double dhat,
                           const bool use_log_barrier = false,
                           const double dmin = 0);
 
        std::string name() const override { return "layer thickness"; }
 
        double max_step_size(const Eigen::VectorXd &x0, const Eigen::VectorXd &x1) const override { return 1.; }
 
    protected:
        void build_collision_mesh();
 
        std::vector<int> boundary_ids_;
        std::map<int, std::set<int>> boundary_ids_to_dof_;
        Eigen::MatrixXi can_collide_cache_;
    };
 
    class DeformedCollisionBarrierForm : public AdjointForm
    {
    public:
        DeformedCollisionBarrierForm(const VariableToSimulationGroup &variable_to_simulation, std::shared_ptr<const varform::DifferentiableVarForm> varform, std::shared_ptr<const DiffCache> diff_cache, const io::ResourceIO &resources, const double dhat);
 
        std::string name() const override { return "deformed_collision_barrier"; }
 
        double value_unweighted(const Eigen::VectorXd &x) const override;
 
        void compute_partial_gradient(const Eigen::VectorXd &x, Eigen::VectorXd &gradv) const override;
 
        void solution_changed(const Eigen::VectorXd &x) override;
 
        bool is_step_collision_free(const Eigen::VectorXd &x0, const Eigen::VectorXd &x1) const override;
 
        double max_step_size(const Eigen::VectorXd &x0, const Eigen::VectorXd &x1) const override;
 
    private:
        void build_collision_set(const Eigen::MatrixXd &displaced_surface);
 
        Eigen::VectorXd get_updated_mesh_nodes(const Eigen::VectorXd &x) const;
 
        std::shared_ptr<const varform::DifferentiableVarForm> varform_;
        std::shared_ptr<const DiffCache> diff_cache_;
 
        Eigen::VectorXd X_init;
 
        ipc::CollisionMesh collision_mesh_;
        ipc::NormalCollisions collision_set;
        const double dhat_;
        ipc::BroadPhaseMethod broad_phase_method_;
 
        const ipc::BarrierPotential barrier_potential_;
    };
 
    class SmoothContactForceForm : public StaticForm
    {
    public:
        SmoothContactForceForm(
            const VariableToSimulationGroup &variable_to_simulations,
            std::shared_ptr<const varform::DifferentiableVarForm> varform,
            std::shared_ptr<const DiffCache> diff_cache,
            const json &args);
        ~SmoothContactForceForm() = default;
 
        double value_unweighted_step(const int time_step, const Eigen::VectorXd &x) const override;
        Eigen::VectorXd compute_adjoint_rhs_step(const int time_step, const Eigen::VectorXd &x, const varform::DifferentiableVarForm &varform, const DiffCache &diff_cache) const override;
        void compute_partial_gradient_step(const int time_step, const Eigen::VectorXd &x, Eigen::VectorXd &gradv) const override;
        void solution_changed_step(const int time_step, const Eigen::VectorXd &x) override;
 
    protected:
        void build_collision_mesh();
        ipc::SmoothCollisions get_smooth_collision_set(const Eigen::MatrixXd &displaced_surface);
 
        std::shared_ptr<const varform::DifferentiableVarForm> varform_;
        std::shared_ptr<const DiffCache> diff_cache_;
        std::set<int> boundary_ids_;
        std::map<int, std::set<int>> boundary_ids_to_dof_;
 
        ipc::CollisionMesh collision_mesh_;
        ipc::SmoothCollisions collisions_;
        const ipc::SmoothContactParameters params_;
        const double dmin_ = 0;
 
        ipc::SmoothContactPotential potential_;
    };
} // namespace polyfem::solver