CompositeForms.cpp

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#include "CompositeForms.hpp"
#include <polyfem/utils/AutodiffTypes.hpp>
 
namespace polyfem::solver
{
    namespace {
        bool delta(int i, int j)
        {
            return (i == j) ? true : false;
        }
 
        double dot(const Eigen::MatrixXd &A, const Eigen::MatrixXd &B) { return (A.array() * B.array()).sum(); }
 
        typedef DScalar1<double, Eigen::Matrix<double, Eigen::Dynamic, 1>> Diff;
 
        template <typename T>
        T homo_stress_aux(const Eigen::Matrix<T, Eigen::Dynamic, 1> &F)
        {
            T val1 = F(0) * F(0) + F(1) * F(1) + F(2) * F(2);
            T val2 = F(3) * F(3);
 
            return sqrt(val1 / (val2 + val1));
        }
 
        Eigen::VectorXd homo_stress_aux_grad(const Eigen::VectorXd &F)
        {
            DiffScalarBase::setVariableCount(F.size());
            Eigen::Matrix<Diff, Eigen::Dynamic, 1> full_diff(F.size());
            for (int i = 0; i < F.size(); i++)
                full_diff(i) = Diff(i, F(i));
            auto reduced_diff = homo_stress_aux(full_diff);
 
            Eigen::VectorXd grad(F.size());
            for (int i = 0; i < F.size(); ++i)
                grad(i) = reduced_diff.getGradient()(i);
 
            return grad;
        }
    }
 
    double HomoCompositeForm::compose(const Eigen::VectorXd &inputs) const
    {
        if (inputs.size() != 4)
            throw std::runtime_error("Invalid input size for HomoCompositeForm!");
        return homo_stress_aux(inputs);
    }
 
    Eigen::VectorXd HomoCompositeForm::compose_grad(const Eigen::VectorXd &inputs) const
    {
        return homo_stress_aux_grad(inputs);
    }
 
    InequalityConstraintForm::InequalityConstraintForm(const std::vector<std::shared_ptr<AdjointForm>> &forms, const Eigen::Vector2d &bounds, const double power) : CompositeForm(forms), power_(power), bounds_(bounds)
    {
        assert(bounds_(1) >= bounds_(0));
    }
 
    double InequalityConstraintForm::compose(const Eigen::VectorXd &inputs) const
    {
        if (inputs.size() != 1)
            throw std::runtime_error("Invalid input size for InequalityConstraintForm!");
        
        return pow(std::max(bounds_(0) - inputs(0), 0.0), power_) + pow(std::max(inputs(0) - bounds_(1), 0.0), power_);
    }
 
    Eigen::VectorXd InequalityConstraintForm::compose_grad(const Eigen::VectorXd &inputs) const
    {
        Eigen::VectorXd grad(1);
        grad(0) = -power_ * pow(std::max(bounds_(0) - inputs(0), 0.0), power_ - 1) + power_ * pow(std::max(inputs(0) - bounds_(1), 0.0), power_ - 1);
        return grad;
    }
}