/** @file
 *
 * @par History
 */


#include "clib.h"
#include "rawtypes.h"

namespace Pol
{
namespace Clib
{
OnlineStatistics::OnlineStatistics() : _count( 0 ), _max( 0 ), _mean( 0 ), _m2( 0 ) {}

void OnlineStatistics::update( double value )
{
  ++_count;
  double delta = value - _mean;
  _mean += delta / _count;
  _m2 += delta * ( value - _mean );
  _max = value > _max ? value : _max;
}

double OnlineStatistics::variance() const
{
  if ( _count < 2 )
    return 0;
  return _m2 / ( _count - 1 );
}

double OnlineStatistics::mean() const
{
  return _mean;
}
u64 OnlineStatistics::count() const
{
  return _count;
}
double OnlineStatistics::max() const
{
  return _max;
}
}
}