// $Id: FeatureSelectorRandom.cc 1392 2008-07-28 19:35:30Z peter $

/*
	Copyright (C) 2006, 2007 Jari Häkkinen, Peter Johansson
	Copyright (C) 2008 Peter Johansson

	This file is part of the yat library, http://dev.thep.lu.se/yat

	The yat library 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 2 of the
	License, or (at your option) any later version.

	The yat 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
	General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
	02111-1307, USA.
*/

#include "FeatureSelectorRandom.h"
#include "MatrixLookup.h"
#include "MatrixLookupWeighted.h"
#include "Target.h"
#include "yat/random/random.h"

#include <algorithm>
#include <cassert>

namespace theplu {
namespace yat {
namespace classifier {


	FeatureSelectorRandom::FeatureSelectorRandom(size_t N)
		: FeatureSelector(N)
	{
	}



	void FeatureSelectorRandom::update(const MatrixLookup& data, 
																		 const Target& target)
	{
		assert(data.columns()==target.size());
		update(data.rows());
	}


	void FeatureSelectorRandom::update(const MatrixLookupWeighted& data, 
																 const Target& target)
	{
		assert(data.columns()==target.size());
		update(data.rows());
	}


	void FeatureSelectorRandom::update(size_t total_N)
	{
		std::vector<size_t>* features = new std::vector<size_t>;
		features->reserve(total_N);
		for (size_t i=0; i<total_N; ++i)
			features->push_back(i);
		// Peter should use random_sample here, but not included in std
		random::random_shuffle(features->begin(), features->end());
		features->resize(N_);
		features_ = 
			utility::Index(utility::SmartPtr<const std::vector<size_t> >(features));
	}

}}} // of namespace classifier, yat, and theplu