dlib C++ Library - average_precision.h

// Copyright (C) 2013 Davis E. King (davis@dlib.net)
// License: Boost Software License See LICENSE.txt for the full license.
#ifndef DLIB_AVERAGE_PREcISION_Hh_
#define DLIB_AVERAGE_PREcISION_Hh_
#include "average_precision_abstract.h"
#include <vector>
namespace dlib
{
 namespace impl
 {
 inline bool get_bool_part (
 const bool& b
 ) { return b; }
 template <typename T>
 bool get_bool_part(const std::pair<T,bool>& item) { return item.second; }
 }
// ----------------------------------------------------------------------------------------
 template <typename T, typename alloc>
 double average_precision (
 const std::vector<T,alloc>& items,
 unsigned long missing_relevant_items = 0
 )
 {
 using namespace dlib::impl;
 double relevant_count = 0;
 // find the precision values
 std::vector<double> precision;
 for (unsigned long i = 0; i < items.size(); ++i)
 {
 if (get_bool_part(items[i]))
 {
 ++relevant_count;
 precision.push_back(relevant_count / (i+1));
 }
 }
 double precision_sum = 0;
 double max_val = 0;
 // now sum over the interpolated precision values
 for (std::vector<double>::reverse_iterator i = precision.rbegin(); i != precision.rend(); ++i)
 {
 max_val = std::max(max_val, *i);
 precision_sum += max_val;
 }
 relevant_count += missing_relevant_items;
 if (relevant_count != 0)
 return precision_sum/relevant_count;
 else
 return 1; 
 }
// ----------------------------------------------------------------------------------------
}
#endif // DLIB_AVERAGE_PREcISION_Hh_