/* ----------------------------------------------------------------------------
	 BinaryTournamentSelector

	 For each generation: Put population in random order, pair up 1/2, 3/4, etc,
	 keep	 best of the two for select(), repeat until n/2 iterations,	repeat 
	 procedure. Each member of the population participates in two tournaments 
	 for each generation. bcw 7/2/99
---------------------------------------------------------------------------- */
#if USE_BINARY_TOURNAMENT_SELECTOR == 1

GAGenome &
GABinaryTournamentSelector::select() const {
	static int curIndex = -1;
	int winIndex = -1;
	float winScore = -1.0;

	if((curIndex < 0) || (curIndex == 2*tournamentN)) {
		curIndex = 0;
	}

	float score1 = pop->individual(tournaments[curIndex]).score();
	float score2 = pop->individual(tournaments[curIndex+1]).score();

	if(score1 > score2) {
		winIndex = curIndex;
		winScore = score1;
	}
	else {
		winIndex = curIndex + 1;
		winScore = score2;
	}

	// debugging info
// 	cout << curIndex / 2;
// 	cout << " winIndex: " << winIndex;
// 	cout << " tournaments[winIndex]: " << tournaments[winIndex];
// 	cout << " string: " << pop->individual(tournaments[winIndex]);
// 	cout << " score: " << winScore << endl << endl;

	curIndex += 2;

	return pop->individual(tournaments[winIndex]);
}

void
GABinaryTournamentSelector::update()
{
	// allocate tournaments array on first run
	if(firstRunFlag == 1) {
		//		cout << "Intializing tournaments storage..." << endl;
		if(tournaments) {
			delete [] tournaments;
		}
		// get population size and make sure it's even for crossover
		n = pop->size();
		if((n % 2) == 1) {
			tournamentN = n + 1;
		}
		else {
			tournamentN = n;
		}
		tournaments = new int[2*tournamentN];
		firstRunFlag = 0;
	}

	// build tournaments array
	//	cout << "Generating tournaments..." << endl;

	// first round of tournaments
	int_gen(tournaments, 0, n-1);
	reorder_ints(tournaments, 0, n-1);

	// second round of tournaments
	int_gen(tournaments+tournamentN, 0, n-1);
	reorder_ints(tournaments+tournamentN, 0, n-1);

	// if odd population size, add another two random ints for extra tournament/
	// selection needed by the crossover operation
	if(tournamentN == n+1) {
		tournaments[tournamentN-1] = GARandomInt(0, n-1);
		tournaments[2*tournamentN-1] = GARandomInt(0, n-1);
	}

// 	for(int i=0; i < 2*tournamentN; i++) {
// 		cout << i << " = " << tournaments[i] << endl;
// 	}
}
#endif