NICE_VisLearning/cbaselib/LabeledSetSelection.h

/** 
* @file LabeledSetSelection.h
* @brief Select a subset of a LabeledSet
* @author Erik Rodner
* @date 02/08/2008

*/
#ifndef LABELEDSETSELECTIONINCLUDE
#define LABELEDSETSELECTIONINCLUDE

#include <vislearning/nice_nonvis.h>

#include <set>
#include <map>
  
namespace OBJREC {

/** Select a subset of a LabeledSet */
template <class F>
class LabeledSetSelection
{

    protected:

    public:
  
	static void selectRandom ( const std::map<int,int> & fixedPositiveExamples, const F & base, F & positive, F & negative )
	{
	    F & base_nonconst = const_cast< F & >(base);
	    //srand(time(NULL));

	    for ( std::map<int,int>::const_iterator i = fixedPositiveExamples.begin(); 
				    i != fixedPositiveExamples.end() ; 
				    i++ )
	    {
			int classno = i->first;
			int fixedPositiveExamples = i->second;

			std::set<int> memory;

			int count = base_nonconst[classno].size();
			if ( (count < fixedPositiveExamples) ) {
				fthrow ( Exception, "LabeledSetSelection::selectRandom: unable to select " << fixedPositiveExamples 
					<< " of " << count << " examples" );
			}

			for ( int j = 0 ; j < fixedPositiveExamples ; j++ )
			{
				int k;
				do {
				k = rand() % count;
				} while ( memory.find(k) != memory.end() );

				memory.insert(k);
				positive.add_reference ( classno, base_nonconst[classno][k]);
			}

			for ( int k = 0 ; k < count ; k++ )
				if ( memory.find(k) == memory.end() )
				negative.add_reference ( classno, base_nonconst[classno][k]);
	    }
	}

	static void selectRandomMax ( const std::map<int,int> & fixedPositiveExamples, const F & base, F & positive, F & negative )
	{
	    F & base_nonconst = const_cast< F & >(base);
	    //srand(time(NULL));

	    for ( std::map<int,int>::const_iterator i = fixedPositiveExamples.begin(); 
				    i != fixedPositiveExamples.end() ; 
				    i++ )
	    {
			int classno = i->first;
			int fixedPositiveExamples = i->second;

			std::set<int> memory;

			int count = base_nonconst[classno].size();

			int m = fixedPositiveExamples < count ? fixedPositiveExamples : count;
			for ( int j = 0 ; j < m ; j++ )
			{
				int k;
				do {
					k = rand() % count;
				} while ( memory.find(k) != memory.end() );

				memory.insert(k);
				positive.add_reference ( classno, base_nonconst[classno][k]);
			}

			for ( int k = 0 ; k < count ; k++ )
				if ( memory.find(k) == memory.end() )
					negative.add_reference ( classno, base_nonconst[classno][k]);
	    }
	}

	static void selectSequentialStep ( const std::map<int, int> & fixedPositiveExamples, const F & base, F & positive, F & negative )
	{
	    F & base_nonconst = const_cast< F & >(base);

	    for ( std::map<int,int>::const_iterator i = fixedPositiveExamples.begin(); 
				    i != fixedPositiveExamples.end() ; 
				    i++ )
	    {
			int classno = i->first;
			int fixedPositiveExamples = i->second;
			int count = base_nonconst[classno].size();
			int step = fixedPositiveExamples ? (count / fixedPositiveExamples) : 0;

			if ( count < fixedPositiveExamples ) {
				fthrow ( Exception, "LabeledSetSelection::selectSequentialStep: unable to select " << fixedPositiveExamples 
						<< " of " << count << " examples (classno " << classno << ")" );
		}


		int k = 0;
		for ( int j = 0 ; j < count ; j++ )
		{
		    if ( (step == 0) || (k >= fixedPositiveExamples) || (j % step != 0) ) 
				negative.add_reference ( classno, base_nonconst[classno][j] );
		    else {
				k++;
				positive.add_reference ( classno, base_nonconst[classno][j] );
		    }
		}
	    }
	};


	static void selectSequential ( const std::map<int, int> & fixedPositiveExamples, const F & base, F & positive, F & negative )
	{
	    F & base_nonconst = const_cast< F & >(base);

	    for ( std::map<int,int>::const_iterator i = fixedPositiveExamples.begin(); 
				    i != fixedPositiveExamples.end() ; 
				    i++ )
	    {
			int classno = i->first;
			int fixedPositiveExamples = i->second;
			int count = base_nonconst[classno].size();

			if ( count < fixedPositiveExamples ) {
				fthrow ( Exception, "LabeledSetSelection::selectSequential: unable to select " << fixedPositiveExamples 
					<< " of " << count << " examples" );
			}

			for ( int j = 0 ; j < fixedPositiveExamples ; j++ )
				positive.add_reference ( classno, base_nonconst[classno][j] );
			
			for ( int j = fixedPositiveExamples ; j < count ; j++ )
				negative.add_reference ( classno, base_nonconst[classno][j] );
	    }

	};

	static void selectClasses ( const std::set<int> & classnos, const F & base, F & positive, F & negative )
	{
	    F & base_nonconst = const_cast< F & >(base);

	    std::vector<int> classes;
	    base.getClasses(classes);

	    for ( std::set<int>::const_iterator i = classnos.begin(); 
				    i != classnos.end() ; 
				    i++ )
	    {
			int classno = *i;
			int count = base_nonconst[classno].size();
			for ( int j = 0 ; j < count ; j++ )
				positive.add_reference ( classno, base_nonconst[classno][j]);
	    }

	    for ( std::vector<int>::const_iterator i = classes.begin(); 
				    i != classes.end() ; 
				    i++ )
	    {
			int classno = *i;
			if ( classnos.find(classno) != classnos.end() ) continue;
			int count = base_nonconst[classno].size();
			for ( int j = 0 ; j < count ; j++ )
				negative.add_reference ( classno, base_nonconst[classno][j]);
	    }

	};

};


} // namespace

#endif