//
//  DualSVC.hpp
//
//  Created by Marc Melikyan on 10/2/20.
//
// http://disp.ee.ntu.edu.tw/~pujols/Support%20Vector%20Machine.pdf
// http://ciml.info/dl/v0_99/ciml-v0_99-ch11.pdf
// Were excellent for the practical intution behind the dual formulation. 

#ifndef DualSVC_hpp
#define DualSVC_hpp


#include <vector>
#include <string>

namespace MLPP {

    class DualSVC{
        
        public:
            DualSVC(std::vector<std::vector<double>> inputSet, std::vector<double> outputSet, double C, std::string kernel = "Linear");
            DualSVC(std::vector<std::vector<double>> inputSet, std::vector<double> outputSet, double C, std::string kernel, double p, double c);

            std::vector<double> modelSetTest(std::vector<std::vector<double>> X);
            double modelTest(std::vector<double> x);
            void gradientDescent(double learning_rate, int max_epoch, bool UI = 1);
            void SGD(double learning_rate, int max_epoch, bool UI = 1);
            void MBGD(double learning_rate, int max_epoch, int mini_batch_size, bool UI = 1);
            double score();
            void save(std::string fileName);
        private:

            void init();

            double Cost(std::vector<double> alpha, std::vector<std::vector<double>> X, std::vector<double> y);
        
            std::vector<double> Evaluate(std::vector<std::vector<double>> X);
            std::vector<double> propagate(std::vector<std::vector<double>> X);
            double Evaluate(std::vector<double> x);
            double propagate(std::vector<double> x);
            void forwardPass();

            void alphaProjection();

            double kernelFunction(std::vector<double> v, std::vector<double> u, std::string kernel);
            std::vector<std::vector<double>> kernelFunction(std::vector<std::vector<double>> U, std::vector<std::vector<double>> V, std::string kernel);
        
            std::vector<std::vector<double>> inputSet;
            std::vector<double> outputSet;
            std::vector<double> z;
            std::vector<double> y_hat;
            double bias;

            std::vector<double> alpha;
            std::vector<std::vector<double>> K;

            double C;
            int n; 
            int k;

            std::string kernel;
            double p; // Poly
            double c; // Poly
        
            // UI Portion
            void UI(int epoch, double cost_prev);        
    };
}

#endif /* DualSVC_hpp */