/**
* This file is part of DSO.
* 
* Copyright 2016 Technical University of Munich and Intel.
* Developed by Jakob Engel <engelj at in dot tum dot de>,
* for more information see <http://vision.in.tum.de/dso>.
* If you use this code, please cite the respective publications as
* listed on the above website.
*
* DSO is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* DSO is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with DSO. If not, see <http://www.gnu.org/licenses/>.
*/


#pragma once

 
#include "util/NumType.h"
#include "util/IndexThreadReduce.h"
#include "OptimizationBackend/MatrixAccumulators.h"
#include "vector"
#include <math.h>

namespace dso
{

class EFPoint;
class EnergyFunctional;


class AccumulatedSCHessianSSE
{
public:
	EIGEN_MAKE_ALIGNED_OPERATOR_NEW;
	inline AccumulatedSCHessianSSE()
	{
		for(int i=0;i<NUM_THREADS;i++) // 多线程
		{
			accE[i]=0;
			accEB[i]=0;
			accD[i]=0;
			nframes[i]=0;
		}
	};
	inline ~AccumulatedSCHessianSSE()
	{
		for(int i=0;i<NUM_THREADS;i++)
		{
			if(accE[i] != 0) delete[] accE[i];
			if(accEB[i] != 0) delete[] accEB[i];
			if(accD[i] != 0) delete[] accD[i];
		}
	};

	inline void setZero(int n, int min=0, int max=1, Vec10* stats=0, int tid=0)
	{
		if(n != nframes[tid])  // 如果帧数有变化
		{
			if(accE[tid] != 0) delete[] accE[tid];
			if(accEB[tid] != 0) delete[] accEB[tid];
			if(accD[tid] != 0) delete[] accD[tid];
			// 这三数组
			accE[tid] = new AccumulatorXX<8,CPARS>[n*n];
			accEB[tid] = new AccumulatorX<8>[n*n];
			accD[tid] = new AccumulatorXX<8,8>[n*n*n];
		}
		accbc[tid].initialize();
		accHcc[tid].initialize();

		for(int i=0;i<n*n;i++)
		{
			accE[tid][i].initialize();
			accEB[tid][i].initialize();

			for(int j=0;j<n;j++)
				accD[tid][i*n+j].initialize();
		}
		nframes[tid]=n;
	}
	void stitchDouble(MatXX &H_sc, VecX &b_sc, EnergyFunctional const * const EF, int tid=0);
	void addPoint(EFPoint* p, bool shiftPriorToZero, int tid=0);

	//@ 多线程得到Schur complement
	void stitchDoubleMT(IndexThreadReduce<Vec10>* red, MatXX &H, VecX &b, EnergyFunctional const * const EF, bool MT)
	{
		// sum up, splitting by bock in square.
		if(MT)
		{
			MatXX Hs[NUM_THREADS];
			VecX bs[NUM_THREADS];
			// 分配空间大小
			for(int i=0;i<NUM_THREADS;i++)
			{
				assert(nframes[0] == nframes[i]);
				Hs[i] = MatXX::Zero(nframes[0]*8+CPARS, nframes[0]*8+CPARS);
				bs[i] = VecX::Zero(nframes[0]*8+CPARS);
			}

			red->reduce(boost::bind(&AccumulatedSCHessianSSE::stitchDoubleInternal,
				this,Hs, bs, EF,  _1, _2, _3, _4), 0, nframes[0]*nframes[0], 0);

			// sum up results
			H = Hs[0];
			b = bs[0];

			for(int i=1;i<NUM_THREADS;i++) 
			{
				H.noalias() += Hs[i];
				b.noalias() += bs[i];
			}
		}
		else
		{
			H = MatXX::Zero(nframes[0]*8+CPARS, nframes[0]*8+CPARS);
			b = VecX::Zero(nframes[0]*8+CPARS);
			stitchDoubleInternal(&H, &b, EF,0,nframes[0]*nframes[0],0,-1);
		}
		
		//* 对称部分
		// make diagonal by copying over parts.
		for(int h=0;h<nframes[0];h++)
		{
			int hIdx = CPARS+h*8;
			H.block<CPARS,8>(0,hIdx).noalias() = H.block<8,CPARS>(hIdx,0).transpose();
		}
	}


	AccumulatorXX<8,CPARS>* accE[NUM_THREADS];			//!< 位姿和内参关于逆深度的 Schur
	AccumulatorX<8>* accEB[NUM_THREADS];				//!< 位姿光度关于逆深度的 b*Schur
	AccumulatorXX<8,8>* accD[NUM_THREADS];				//!< 两位姿光度关于逆深度的 Schur

	AccumulatorXX<CPARS,CPARS> accHcc[NUM_THREADS];		//!< 内参关于逆深度的 Schur
	AccumulatorX<CPARS> accbc[NUM_THREADS];				//!< 内参关于逆深度的 b*Schur
	int nframes[NUM_THREADS];


	void addPointsInternal(
			std::vector<EFPoint*>* points, bool shiftPriorToZero,
			int min=0, int max=1, Vec10* stats=0, int tid=0)
	{
		for(int i=min;i<max;i++) addPoint((*points)[i],shiftPriorToZero,tid);
	}

private:

	void stitchDoubleInternal(
			MatXX* H, VecX* b, EnergyFunctional const * const EF,
			int min, int max, Vec10* stats, int tid);
};

}

