Sparse_HTST.hpp

#pragma once
#ifndef SPARSE_HTST_H
#define SPARSE_HTST_H
#ifndef SPIRIT_SKIP_HTST

#include "Spirit_Defines.h"
#include <iostream>
#include <fstream>
#include <data/Spin_System.hpp>
#include <data/Spin_System_Chain.hpp>
#include <engine/Vectormath_Defines.hpp>

namespace Engine
{
    namespace Sparse_HTST
    {
        // A small function for debugging purposes
        inline void saveMatrix(std::string fname, const SpMatrixX & matrix)
        {
            std::cout << "Saving matrix to file: " << fname << "\n";
            std::ofstream file(fname);
            if(file && file.is_open())
            {
                file << matrix;
            } else {
                std::cerr << "Could not save matrix!";
            }
        }

        template<typename Field_Like>
        inline void saveField(std::string fname, const Field_Like & field)
        {
            int n = field.size();
            std::cout << "Saving field to file: " << fname << "\n";
            std::ofstream file(fname);
            if(file && file.is_open())
            {
                for(int i=0; i<n; i++)
                    file << field[i] << "\n";
            } else {
                std::cerr << "Could not save field!";
            }
        }

        // Note the two images should correspond to one minimum and one saddle point
        void Calculate(Data::HTST_Info & htst_info);

        // Calculate the sparse Velocity matrix
        void Sparse_Calculate_Dynamical_Matrix(const vectorfield & spins, const scalarfield & mu_s, const SpMatrixX & hessian, SpMatrixX & velocity);

        void Sparse_Geodesic_Eigen_Decomposition(const vectorfield & image, const vectorfield & gradient, const SpMatrixX & hessian,
            SpMatrixX & hessian_geodesic_3N, SpMatrixX & hessian_geodesic_2N, SpMatrixX & tangent_basis, VectorX & eigenvalues, MatrixX & eigenvectors);

        void sparse_hessian_bordered_3N(const vectorfield & image, const vectorfield & gradient, const SpMatrixX & hessian, SpMatrixX & hessian_out);

    };
}

#endif
#endif