/* -*- mode: C++; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
// vim:sts=4:sw=4:ts=4:noet:sr:cino=>s,f0,{0,g0,(0,\:0,t0,+0,=s

/*
 * Copyright (C) 2016 FFLAS-FFPACK group.
 *
 * Written by Clément Pernet <clement.pernet@imag.fr>
 * Philippe LEDENT <philippe.ledent@etu.univ-grenoble-alpes.fr>
 *
 * ========LICENCE========
 * This file is part of the library FFLAS-FFPACK.
 *
 * FFLAS-FFPACK 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
 * ========LICENCE========
 *
 */



#include "fflas-ffpack/fflas-ffpack-config.h"
#include "fflas-ffpack/utils/fflas_randommatrix.h"
#include <iostream>
#include <givaro/modular-balanced.h>
#include "fflas-ffpack/utils/timer.h"
#include "fflas-ffpack/ffpack/ffpack.h"


#ifdef __GIVARO_USE_OPENMP
typedef Givaro::OMPTimer TTimer;
#else
typedef Givaro::Timer TTimer;
#endif

#include <ctime>
#define CUBE(x) ((x)*(x)*(x))
#define GFOPS(n,t) (CUBE(double(n)/1000.0)/(3.0*t))

int main () {
	using namespace std;

	typedef Givaro::ModularBalanced<double> Field;
	Field F(131071);
	size_t n=64, nmax=500, prec=64, nbest=0, count=0;
	TTimer chrono,tim;
	bool bound=false;
	
	Field::Element_ptr T = FFLAS::fflas_new (F, nmax, nmax);
	size_t ldt = nmax;
	FFPACK::RandomTriangularMatrix (F, n, n,
									FFLAS::FflasUpper,FFLAS::FflasNonUnit,true,
									T,ldt);
	time_t result = std::time(NULL);
	Field::Element_ptr U = FFLAS::fflas_new (F, nmax, nmax);
	FFLAS::fassign (F, n, n, U, ldt, T, ldt);
	cerr << std::endl 
		 << "---------------------------------------------------------------------"
		 << std::endl << std::asctime(std::localtime(&result))
		 << std::endl
		 << "Threshold for ftrtri base case" ;
	F.write(cerr << " (using ") << ')' << endl << endl;

	cerr << "ftrtri:  n                   Base case                        Recursive 1 level" << std::endl;
	cerr << "                    seconds            Gfops          seconds            Gfops" << std::endl;
	double BCTime, RecTime;
	int iter;
	do{
		iter=300;

			//warm up computation
		FFPACK::ftrtri(F, FFLAS::FflasUpper, FFLAS::FflasNonUnit, n, U, ldt, n);
		FFLAS::fassign (F, n, n, T, ldt, U, ldt);
		
			// base case
		chrono.clear();tim.clear();
		for (int i=0;i<iter;i++){
			chrono.start();
			FFPACK::ftrtri(F, FFLAS::FflasUpper, FFLAS::FflasNonUnit, n, U, ldt, n);
			chrono.stop();
			tim+=chrono;
			FFLAS::fassign (F, n, n, T, ldt, U, ldt);
		}
		BCTime = tim.usertime()/iter;
		
		tim.clear();chrono.clear();
		for (int i=0;i<iter;i++){
			chrono.start();
			FFPACK::ftrtri(F, FFLAS::FflasUpper, FFLAS::FflasNonUnit, n, U, ldt, n-1);
			chrono.stop();
			tim+=chrono;
			FFLAS::fassign (F, n, n, T, ldt, U, ldt);
		}
		RecTime = tim.realtime()/iter;

		cerr << "      ";
		cerr.width(4);
		cerr << n;
		cerr << "  ";
		cerr.width(15);
		cerr << BCTime;
		cerr << "  ";
		cerr.width(15);
		cerr << GFOPS(n, BCTime) << "  ";
		cerr.width(15);
		cerr << RecTime;
		cerr << "  ";
		cerr.width(15);
		cerr << GFOPS(n, RecTime) << endl;

		if (BCTime > RecTime){
			count++;
			if (count > 2){
				nbest = n;
				bound = true;
				prec = prec >> 1;
				n -= prec;
			}
		}
		else{
			count=0;
			if (bound)
				prec=prec>>1;
			n+=prec;
		}
	} while ((prec > 1 ) && (n < nmax));

	cerr<<endl;
	if (nbest != 0 ) {
		cout << "#ifndef __FFLASFFPACK_FTRTRI_THRESHOLD"  << endl;
		cout << "#define __FFLASFFPACK_FTRTRI_THRESHOLD" << ' ' <<  nbest << endl;
		cerr << "defined __FFLASFFPACK_FTRTRI_THRESHOLD to " << nbest << "" << std::endl;
		std::cout << "#endif" << endl  << endl;
	}
	FFLAS::fflas_delete(T);
	FFLAS::fflas_delete(U);
	
	return 0;
}