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// Copyright (C) 2013 Davis E. King (davis@dlib.net)
// License: Boost Software License See LICENSE.txt for the full license.
#ifndef DLIB_CROSS_VALIDATE_SEQUENCE_sEGMENTER_Hh_
#define DLIB_CROSS_VALIDATE_SEQUENCE_sEGMENTER_Hh_
#include "cross_validate_sequence_segmenter_abstract.h"
#include "sequence_segmenter.h"
namespace dlib
{
// ----------------------------------------------------------------------------------------
namespace impl
{
template <
typename sequence_segmenter_type,
typename sequence_type
>
const matrix<double,1,3> raw_metrics_test_sequence_segmenter (
const sequence_segmenter_type& segmenter,
const std::vector<sequence_type>& samples,
const std::vector<std::vector<std::pair<unsigned long,unsigned long> > >& segments
)
{
std::vector<std::pair<unsigned long,unsigned long> > truth;
std::vector<std::pair<unsigned long,unsigned long> > pred;
double true_hits = 0;
double total_detections = 0;
double total_true_segments = 0;
for (unsigned long i = 0; i < samples.size(); ++i)
{
segmenter.segment_sequence(samples[i], pred);
truth = segments[i];
// sort the segments so they will be in the same orders
std::sort(truth.begin(), truth.end());
std::sort(pred.begin(), pred.end());
total_true_segments += truth.size();
total_detections += pred.size();
unsigned long j=0,k=0;
while (j < pred.size() && k < truth.size())
{
if (pred[j].first == truth[k].first &&
pred[j].second == truth[k].second)
{
++true_hits;
++j;
++k;
}
else if (pred[j].first < truth[k].first)
{
++j;
}
else
{
++k;
}
}
}
matrix<double,1,3> res;
res = total_detections, total_true_segments, true_hits;
return res;
}
}
// ----------------------------------------------------------------------------------------
template <
typename sequence_segmenter_type,
typename sequence_type
>
const matrix<double,1,3> test_sequence_segmenter (
const sequence_segmenter_type& segmenter,
const std::vector<sequence_type>& samples,
const std::vector<std::vector<std::pair<unsigned long,unsigned long> > >& segments
)
{
// make sure requires clause is not broken
DLIB_ASSERT( is_sequence_segmentation_problem(samples, segments) == true,
"\tmatrix test_sequence_segmenter()"
<< "\n\t invalid inputs were given to this function"
<< "\n\t is_sequence_segmentation_problem(samples, segments): "
<< is_sequence_segmentation_problem(samples, segments));
const matrix<double,1,3> metrics = impl::raw_metrics_test_sequence_segmenter(segmenter, samples, segments);
const double total_detections = metrics(0);
const double total_true_segments = metrics(1);
const double true_hits = metrics(2);
const double precision = (total_detections ==0) ? 1 : true_hits/total_detections;
const double recall = (total_true_segments==0) ? 1 : true_hits/total_true_segments;
const double f1 = (precision+recall ==0) ? 0 : 2*precision*recall/(precision+recall);
matrix<double,1,3> res;
res = precision, recall, f1;
return res;
}
// ----------------------------------------------------------------------------------------
template <
typename trainer_type,
typename sequence_type
>
const matrix<double,1,3> cross_validate_sequence_segmenter (
const trainer_type& trainer,
const std::vector<sequence_type>& samples,
const std::vector<std::vector<std::pair<unsigned long,unsigned long> > >& segments,
const long folds
)
{
// make sure requires clause is not broken
DLIB_ASSERT( is_sequence_segmentation_problem(samples, segments) == true &&
1 < folds && folds <= static_cast<long>(samples.size()),
"\tmatrix cross_validate_sequence_segmenter()"
<< "\n\t invalid inputs were given to this function"
<< "\n\t folds: " << folds
<< "\n\t is_sequence_segmentation_problem(samples, segments): "
<< is_sequence_segmentation_problem(samples, segments));
const long num_in_test = samples.size()/folds;
const long num_in_train = samples.size() - num_in_test;
std::vector<sequence_type> x_test, x_train;
std::vector<std::vector<std::pair<unsigned long,unsigned long> > > y_test, y_train;
long next_test_idx = 0;
matrix<double,1,3> metrics;
metrics = 0;
for (long i = 0; i < folds; ++i)
{
x_test.clear();
y_test.clear();
x_train.clear();
y_train.clear();
// load up the test samples
for (long cnt = 0; cnt < num_in_test; ++cnt)
{
x_test.push_back(samples[next_test_idx]);
y_test.push_back(segments[next_test_idx]);
next_test_idx = (next_test_idx + 1)%samples.size();
}
// load up the training samples
long next = next_test_idx;
for (long cnt = 0; cnt < num_in_train; ++cnt)
{
x_train.push_back(samples[next]);
y_train.push_back(segments[next]);
next = (next + 1)%samples.size();
}
metrics += impl::raw_metrics_test_sequence_segmenter(trainer.train(x_train,y_train), x_test, y_test);
} // for (long i = 0; i < folds; ++i)
const double total_detections = metrics(0);
const double total_true_segments = metrics(1);
const double true_hits = metrics(2);
const double precision = (total_detections ==0) ? 1 : true_hits/total_detections;
const double recall = (total_true_segments==0) ? 1 : true_hits/total_true_segments;
const double f1 = (precision+recall ==0) ? 0 : 2*precision*recall/(precision+recall);
matrix<double,1,3> res;
res = precision, recall, f1;
return res;
}
// ----------------------------------------------------------------------------------------
}
#endif // DLIB_CROSS_VALIDATE_SEQUENCE_sEGMENTER_Hh_
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