/******************************************************************************
*       SOFA, Simulation Open-Framework Architecture, version 1.0 beta 4      *
*                (c) 2006-2009 MGH, INRIA, USTL, UJF, CNRS                    *
*                                                                             *
* This library is free software; you can redistribute it and/or modify it     *
* under the terms of the GNU Lesser General Public License as published by    *
* the Free Software Foundation; either version 2.1 of the License, or (at     *
* your option) any later version.                                             *
*                                                                             *
* This library 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 Lesser General Public License *
* for more details.                                                           *
*                                                                             *
* You should have received a copy of the GNU Lesser General Public License    *
* along with this library; if not, write to the Free Software Foundation,     *
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.          *
*******************************************************************************
*                               SOFA :: Modules                               *
*                                                                             *
* Authors: The SOFA Team and external contributors (see Authors.txt)          *
*                                                                             *
* Contact information: contact@sofa-framework.org                             *
******************************************************************************/
// Author: Hadrien Courtecuisse
//
// Copyright: See COPYING file that comes with this distribution
#include <sofa/component/linearsolver/PCGLinearSolver.h>
#include <sofa/component/linearsolver/NewMatMatrix.h>
#include <sofa/component/linearsolver/FullMatrix.h>
#include <sofa/component/linearsolver/SparseMatrix.h>
#include <sofa/core/ObjectFactory.h>
#include <iostream>
#include "sofa/helper/system/thread/CTime.h"
#include <sofa/core/objectmodel/BaseContext.h>
#include <sofa/core/componentmodel/behavior/LinearSolver.h>
#include <sofa/helper/system/thread/CTime.h>

namespace sofa
{

namespace component
{

namespace linearsolver
{

using namespace sofa::defaulttype;
using namespace sofa::core::componentmodel::behavior;
using namespace sofa::simulation;
using namespace sofa::core::objectmodel;
using sofa::helper::system::thread::CTime;
using sofa::helper::system::thread::ctime_t;
using std::cerr;
using std::endl;

template<class TMatrix, class TVector>
void PCGLinearSolver<TMatrix,TVector>::init() {
	std::vector<sofa::core::componentmodel::behavior::LinearSolver*> solvers;
	BaseContext * c = this->getContext();
	c->get<LinearSolver>(&solvers,BaseContext::SearchDown);

	for (unsigned int i=0;i<solvers.size();++i) {
		if (solvers[i] != this) {
			this->preconditioners.push_back(solvers[i]);
		}
	}
}

template<class TMatrix, class TVector>
void PCGLinearSolver<TMatrix,TVector>::setSystemMBKMatrix(double mFact, double bFact, double kFact) {
	Inherit::setSystemMBKMatrix(mFact,bFact,kFact);

#ifdef DISPLAY_TIME
		time3 = (double) CTime::getTime();
#endif

	no_precond = use_precond.getValue();

	if (no_precond) {
		if (iteration<=0) {
			for (unsigned int i=0;i<this->preconditioners.size();++i) {
				preconditioners[i]->setSystemMBKMatrix(mFact,bFact,kFact);
			}
			iteration = f_refresh.getValue();
		} else {
			iteration--;
		}
	}

#ifdef DISPLAY_TIME
		time3 = ((double) CTime::getTime() - time3) / (double)CTime::getRefTicksPerSec();
#endif

}

/*
template<class TMatrix, class TVector>
void PCGLinearSolver<TMatrix,TVector>::setSystemRHVector(VecId v) {
	Inherit::setSystemRHVector(v);

	for (unsigned int i=0;i<this->preconditioners.size();++i) {
		preconditioners[i]->setSystemRHVector(v);
	}
}

template<class TMatrix, class TVector>
void PCGLinearSolver<TMatrix,TVector>::setSystemLHVector(VecId v) {
	Inherit::setSystemLHVector(v);

	for (unsigned int i=0;i<this->preconditioners.size();++i) {
		preconditioners[i]->setSystemLHVector(v);
	}
}
*/

template<class TMatrix, class TVector>
void PCGLinearSolver<TMatrix,TVector>::solve (Matrix& M, Vector& x, Vector& b) {
	using std::cerr;
	using std::endl;

	Vector& p = *this->createVector();
	Vector& q = *this->createVector();
	Vector& r = *this->createVector();
	Vector& z = *this->createVector();

	const bool printLog = f_printLog.getValue();
	const bool verbose  = f_verbose.getValue();

	// -- solve the system using a conjugate gradient solution
	double rho, rho_1=0, alpha, beta;

	if( verbose )
		cerr<<"PCGLinearSolver, b = "<< b <<endl;

	x.clear();
	r = b; // initial residual

	double normb2 = b.dot(b);
	double normb = sqrt(normb2);
	std::map < std::string, sofa::helper::vector<double> >& graph = *f_graph.beginEdit();
	sofa::helper::vector<double>& graph_error = graph["Error"];
	graph_error.clear();
	sofa::helper::vector<double>& graph_den = graph["Denominator"];
	graph_den.clear();
	graph_error.push_back(1);
	unsigned nb_iter;
	const char* endcond = "iterations";

#ifdef DISPLAY_TIME
	time1 = 0.0;
	time2 = 0.0;
	time4 = 0.0;
#endif

	for( nb_iter=1; nb_iter<=f_maxIter.getValue(); nb_iter++ ) {

#ifdef DUMP_VISITOR_INFO
  std::ostringstream comment;
  comment << "Iteration : " << nb_iter;
  simulation::Visitor::printComment(comment.str());
#endif
#ifdef DISPLAY_TIME
		double tmp;
#endif
		if (this->preconditioners.size()==0 || (!no_precond)) {
			z = r;
		} else {
			for (unsigned int i=0;i<this->preconditioners.size();i++) {
#ifdef DISPLAY_TIME
			tmp = (double) CTime::getTime();
#endif
				preconditioners[i]->setSystemLHVector(z);
				preconditioners[i]->setSystemRHVector(r);
#ifdef DISPLAY_TIME
			time2 += ((double) CTime::getTime() - tmp);
			tmp = (double) CTime::getTime();
#endif
				preconditioners[i]->invertSystem();
#ifdef DISPLAY_TIME
			time4 += ((double) CTime::getTime() - tmp);
			tmp = (double) CTime::getTime();
#endif
				preconditioners[i]->solveSystem();
#ifdef DISPLAY_TIME
			time2 += ((double) CTime::getTime() - tmp);
#endif
			}
        }
#ifdef DISPLAY_TIME
		tmp = (double) CTime::getTime();
#endif
		rho = r.dot(z);

		if (nb_iter>1) {
			double normr = sqrt(r.dot(r));
			double err = normr/normb;
			graph_error.push_back(err);
			if (err <= f_tolerance.getValue()) {
				endcond = "tolerance";
				break;
			}
		}

		if( nb_iter==1 ) p = z;
		else {
			beta = rho / rho_1;
			//p = p*beta + z;
			cgstep_beta(p,z,beta);
		}

		if( verbose ) {
			cerr<<"p : "<<p<<endl;
		}

		// matrix-vector product
		q = M*p;

		if( verbose ) {
			cerr<<"q = M p : "<<q<<endl;
		}

		double den = p.dot(q);

		graph_den.push_back(den);

		if( fabs(den)<f_smallDenominatorThreshold.getValue() ) {
			endcond = "threshold";
			if( verbose )
			{
				cerr<<"PCGLinearSolver, den = "<<den<<", smallDenominatorThreshold = "<<f_smallDenominatorThreshold.getValue()<<endl;
			}
			break;
		}

		alpha = rho/den;
		//x.peq(p,alpha);                 // x = x + alpha p
		//r.peq(q,-alpha);                // r = r - alpha q
		cgstep_alpha(x,r,p,q,alpha);

		if( verbose ) {
			cerr<<"den = "<<den<<", alpha = "<<alpha<<endl;
			cerr<<"x : "<<x<<endl;
			cerr<<"r : "<<r<<endl;
		}

		rho_1 = rho;

#ifdef DISPLAY_TIME
			time1 += ((double) CTime::getTime() - tmp);
#endif
		//printf("%f\n",(CTime::getRefTime() - time1)  / (double)CTime::getRefTicksPerSec());

	}

#ifdef DISPLAY_TIME
	time1 = time1 / (double)((double)CTime::getRefTicksPerSec() * (nb_iter-1));
	time2 = time2 / (double)((double)CTime::getRefTicksPerSec() * (nb_iter-1));
	time4 = time4 / (double)((double)CTime::getRefTicksPerSec());
#endif

	f_graph.endEdit();
	// x is the solution of the system
	if( printLog )
	{
#ifdef DISPLAY_TIME
		cerr<<"PCGLinearSolver::solve, CG = "<<time1<<" preconditioner = "<<time2<<" build = "<<time3<<" invert = "<<time4<<endl;
#endif
		cerr<<"PCGLinearSolver::solve, nbiter = "<<nb_iter<<" stop because of "<<endcond<<endl;
	}
	if( verbose )
	{
		cerr<<"PCGLinearSolver::solve, solution = "<<x<<endl;
	}
	this->deleteVector(&p);
	this->deleteVector(&q);
	this->deleteVector(&r);
	this->deleteVector(&z);

}

SOFA_DECL_CLASS(PCGLinearSolver)

int PCGLinearSolverClass = core::RegisterObject("Linear system solver using the conjugate gradient iterative algorithm")
.add< PCGLinearSolver<GraphScatteredMatrix,GraphScatteredVector> >(true)
//.add< PCGLinearSolver<NewMatMatrix,NewMatVector> >()
//.add< PCGLinearSolver<NewMatSymmetricMatrix,NewMatVector> >()
//.add< PCGLinearSolver<NewMatBandMatrix,NewMatVector> >()
//.add< PCGLinearSolver<NewMatSymmetricBandMatrix,NewMatVector> >()
//.add< PCGLinearSolver< FullMatrix<double>, FullVector<double> > >()
//.add< PCGLinearSolver< SparseMatrix<double>, FullVector<double> > >()
.addAlias("PCGSolver")
.addAlias("PConjugateGradient")
;

} // namespace linearsolver

} // namespace component

} // namespace sofa