/*
 * VarFunc.hh
 *
 *  Created on: Jun 22, 2018
 *      Author: benjamin
 */

#ifndef VARFUNC_HH_
#define VARFUNC_HH_

#include "AbstractFunc.hh"
#include "Toolbox.hh"

namespace AMDA {
namespace Parameters {
namespace StatisticFunctions {

template <typename InputElemType, typename OutputElemType>
OutputElemType computeVar(std::list<std::pair<double,InputElemType>>& mem, OutputElemType& nanVal) {
	OutputElemType result = nanVal;
	if (mem.empty()) {
		return result;
	}
	result << ElemNull();
	OutputElemType sum = result;
	int n = 0;
	for (auto val : mem) {
		if (isNAN(val.second))
			continue;
		sum = sum+val.second;
		result = result+StatisticFunctions::square(val.second);
		++n;
	}
	if (n == 0) {
		result << NotANumber();
		return result;
	}
	result = 1./n*result;
	OutputElemType mean = sum/n;
	result = result - StatisticFunctions::square(mean);
	return result;
}

/**
 * @class VarFunc
 * @brief 
 * @details This class implements AbstractFunc.
 */
template <typename InputElemType, typename OutputElemType> 
class VarFunc : public ClassicAbstractFunc<InputElemType,OutputElemType> {
public:
	/**
	 * @brief Constructor.
	 */
	VarFunc(Process& pProcess, TimeIntervalListSPtr pTimeIntervalList, ParamDataSpec<InputElemType>& paramInput, double windowtime)
	: ClassicAbstractFunc<InputElemType,OutputElemType>(pProcess, pTimeIntervalList, paramInput, windowtime) {
	}

	virtual ~VarFunc() {
	}

	OutputElemType compute() {
		return computeVar(ClassicAbstractFunc<InputElemType,OutputElemType>::_mem, ClassicAbstractFunc<InputElemType,OutputElemType>::_nanVal);
	}
};  

/**
 * @class VarFuncSm
 * @brief
 * @details This class implements AbstractFunc.
 */
template <typename InputElemType, typename OutputElemType>
class VarSmFunc : public SmAbstractFunc<InputElemType,OutputElemType> {
public:
	/**
	 * @brief Constructor.
	 */
	VarSmFunc(Process& pProcess, TimeIntervalListSPtr pTimeIntervalList, ParamDataSpec<InputElemType>& paramInput, double windowtime)
	: SmAbstractFunc<InputElemType,OutputElemType>(pProcess, pTimeIntervalList, paramInput, windowtime) {
        }

	virtual ~VarSmFunc() {
	}

	OutputElemType compute() {
		return computeVar(SmAbstractFunc<InputElemType,OutputElemType>::_mem, SmAbstractFunc<InputElemType,OutputElemType>::_nanVal);
        }
};


} /* namespace StatisticFunctions */
} /* namespace Parameters */
} /* namespace AMDA */
#endif /* MINFUNC_HH_ */