#ifndef _BACK_PROPAGATION_H_
#define _BACK_PROPAGATION_H_

#include <math.h>
#include <thread>
#include <cstddef>

#include "../LayerNetwork.h"
#include  "Learning.h"

/*
 * http://sydney.edu.au/engineering/it/~comp4302/ann4-3s.pdf
 * http://www.cs.cmu.edu/afs/cs/academic/class/15883-f13/slides/backprop.pdf
 * http://airccse.org/journal/jcsit/0211ijcsit08.pdf
 * http://www.cedar.buffalo.edu/~srihari/CSE574/Chap5/Chap5.3-BackProp.pdf
 * http://stackoverflow.com/questions/13095938/can-somebody-please-explain-the-backpropagation-algorithm-to-me
 * http://ufldl.stanford.edu/wiki/index.php/Backpropagation_Algorithm
 * 
 * http://www.cleveralgorithms.com/nature-inspired/neural/backpropagation.html
 * 
 */

namespace NeuralNetwork
{
namespace Learning
{
	class BackPropagation : public Learning
	{
		public:
			BackPropagation(LayerNetwork &n): Learning(), network(n) {}
			virtual ~BackPropagation();

			BackPropagation(const NeuralNetwork::Learning::BackPropagation&) =delete;
			BackPropagation operator=(const NeuralNetwork::Learning::BackPropagation&) =delete;

			float teach(const std::vector<float>&p,const std::vector<float>&solution);
			virtual void propagate(const std::vector<float>& expectation);

		protected:
			LayerNetwork &network;
			inline virtual float correction(const float& expected, const float& computed) { return expected - computed;};

			float **deltas=nullptr;
	};
}
}
#endif