#include "AlgMostPopular.h"

#include "MaxHeap.h"

#include "ProgressBar.h"

using namespace std;

AlgMostPopular::AlgMostPopular( DataReader& dreader,

int userpos,

int itempos,

int ratingpos )

: RecSysAlgorithm< boost::numeric::ublas::mapped_matrix<double, boost::numeric::ublas::row_major> >( dreader, userpos, itempos, ratingpos )

{

}

int AlgMostPopular::train( FlowControl& fcontrol, bool progress )

{

size_t nitems = m_ratingMatrix.items();

ProgressBar pbar( nitems, progress );

for( size_t i = 0 ; i < nitems ; ++i )

{

double score = m_ratingMatrix.nonZeroCol( i );

pair<double, size_t> e = pair<double, size_t>( score, i );

m_itemList.push_back( e );

if( fcontrol.interrupt() )

{

sort( m_itemList.rbegin(), m_itemList.rend() );

return STOPPED;

}

pbar.update( i + 1 );

}

sort( m_itemList.rbegin(), m_itemList.rend() );

return FINISHED;

}

bool AlgMostPopular::recommend( const std::string& userId,

size_t n,

std::vector<std::string>& ranking,

bool includeRated )

{

int row = m_ratingMatrix.row( userId );

size_t nitems = m_itemList.size();

for( size_t col = 0 ; col < nitems ; ++col )

{

if( includeRated || ( 0 == m_ratingMatrix.get( row, col ) ) )

{

size_t itemcol = m_itemList[col].second;

string itemId = m_ratingMatrix.itemId( itemcol );

ranking.push_back( itemId );

if( ranking.size() == n )

{

break;

}

}

}

return true;

}