// Copyright (C) 2015 Davis E. King (davis@dlib.net)
// License: Boost Software License See LICENSE.txt for the full license.
#ifndef DLIB_DNn_LOSS_H_
#define DLIB_DNn_LOSS_H_
#include "loss_abstract.h"
#include "core.h"
#include "utilities.h"
#include "../matrix.h"
#include "../cuda/tensor_tools.h"
#include "../geometry.h"
#include "../image_processing/box_overlap_testing.h"
#include "../image_processing/full_object_detection.h"
#include "../svm/ranking_tools.h"
#include <sstream>
#include <map>
#include <unordered_map>
namespace dlib
{
// ----------------------------------------------------------------------------------------
class loss_binary_hinge_
{
public:
typedef float training_label_type;
typedef float output_label_type;
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
) const
{
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1 &&
output_tensor.k() == 1);
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
*iter++ = out_data[i];
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1 &&
output_tensor.k() == 1);
// The loss we output is the average loss over the mini-batch.
const double scale = 1.0/output_tensor.num_samples();
double loss = 0;
const float* out_data = output_tensor.host();
float* g = grad.host_write_only();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
const float y = *truth++;
DLIB_CASSERT(y == +1 || y == -1, "y: " << y);
const float temp = 1-y*out_data[i];
if (temp > 0)
{
loss += scale*temp;
g[i] = -scale*y;
}
else
{
g[i] = 0;
}
}
return loss;
}
friend void serialize(const loss_binary_hinge_& , std::ostream& out)
{
serialize("loss_binary_hinge_", out);
}
friend void deserialize(loss_binary_hinge_& , std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_binary_hinge_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_binary_hinge_.");
}
friend std::ostream& operator<<(std::ostream& out, const loss_binary_hinge_& )
{
out << "loss_binary_hinge";
return out;
}
friend void to_xml(const loss_binary_hinge_& /*item*/, std::ostream& out)
{
out << "<loss_binary_hinge/>";
}
};
template <typename SUBNET>
using loss_binary_hinge = add_loss_layer<loss_binary_hinge_, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_binary_log_
{
public:
typedef float training_label_type;
typedef float output_label_type;
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
) const
{
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1 &&
output_tensor.k() == 1);
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
*iter++ = out_data[i];
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1 &&
output_tensor.k() == 1);
DLIB_CASSERT(grad.nr() == 1 &&
grad.nc() == 1 &&
grad.k() == 1);
tt::sigmoid(grad, output_tensor);
// The loss we output is the average loss over the mini-batch.
const double scale = 1.0/output_tensor.num_samples();
double loss = 0;
float* g = grad.host();
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
const float y = *truth++;
DLIB_CASSERT(y != 0, "y: " << y);
float temp;
if (y > 0)
{
temp = log1pexp(-out_data[i]);
loss += y*scale*temp;
g[i] = y*scale*(g[i]-1);
}
else
{
temp = -(-out_data[i]-log1pexp(-out_data[i]));
loss += -y*scale*temp;
g[i] = -y*scale*g[i];
}
}
return loss;
}
friend void serialize(const loss_binary_log_& , std::ostream& out)
{
serialize("loss_binary_log_", out);
}
friend void deserialize(loss_binary_log_& , std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_binary_log_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_binary_log_.");
}
friend std::ostream& operator<<(std::ostream& out, const loss_binary_log_& )
{
out << "loss_binary_log";
return out;
}
friend void to_xml(const loss_binary_log_& /*item*/, std::ostream& out)
{
out << "<loss_binary_log/>";
}
};
template <typename SUBNET>
using loss_binary_log = add_loss_layer<loss_binary_log_, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_multiclass_log_
{
public:
typedef unsigned long training_label_type;
typedef unsigned long output_label_type;
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
) const
{
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1 );
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
// Note that output_tensor.k() should match the number of labels.
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
// The index of the largest output for this sample is the label.
*iter++ = index_of_max(rowm(mat(output_tensor),i));
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1);
DLIB_CASSERT(grad.nr() == 1 &&
grad.nc() == 1);
tt::softmax(grad, output_tensor);
// The loss we output is the average loss over the mini-batch.
const double scale = 1.0/output_tensor.num_samples();
double loss = 0;
float* g = grad.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
const long y = (long)*truth++;
// The network must produce a number of outputs that is equal to the number
// of labels when using this type of loss.
DLIB_CASSERT(y < output_tensor.k(), "y: " << y << ", output_tensor.k(): " << output_tensor.k());
for (long k = 0; k < output_tensor.k(); ++k)
{
const unsigned long idx = i*output_tensor.k()+k;
if (k == y)
{
loss += scale*-safe_log(g[idx]);
g[idx] = scale*(g[idx]-1);
}
else
{
g[idx] = scale*g[idx];
}
}
}
return loss;
}
friend void serialize(const loss_multiclass_log_& , std::ostream& out)
{
serialize("loss_multiclass_log_", out);
}
friend void deserialize(loss_multiclass_log_& , std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_multiclass_log_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_multiclass_log_.");
}
friend std::ostream& operator<<(std::ostream& out, const loss_multiclass_log_& )
{
out << "loss_multiclass_log";
return out;
}
friend void to_xml(const loss_multiclass_log_& /*item*/, std::ostream& out)
{
out << "<loss_multiclass_log/>";
}
};
template <typename SUBNET>
using loss_multiclass_log = add_loss_layer<loss_multiclass_log_, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_multiclass_log_weighted_
{
public:
typedef dlib::weighted_label<unsigned long> weighted_label;
typedef weighted_label training_label_type;
typedef unsigned long output_label_type;
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
) const
{
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1 );
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
// Note that output_tensor.k() should match the number of labels.
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
// The index of the largest output for this sample is the label.
*iter++ = index_of_max(rowm(mat(output_tensor),i));
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1);
DLIB_CASSERT(grad.nr() == 1 &&
grad.nc() == 1);
tt::softmax(grad, output_tensor);
// The loss we output is the average loss over the mini-batch.
const double scale = 1.0/output_tensor.num_samples();
double loss = 0;
float* g = grad.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
const auto wl = *truth++;
const long y = wl.label;
const float weight = wl.weight;
// The network must produce a number of outputs that is equal to the number
// of labels when using this type of loss.
DLIB_CASSERT(y < output_tensor.k(), "y: " << y << ", output_tensor.k(): " << output_tensor.k());
for (long k = 0; k < output_tensor.k(); ++k)
{
const unsigned long idx = i*output_tensor.k()+k;
if (k == y)
{
loss += weight*scale*-safe_log(g[idx]);
g[idx] =weight*scale*(g[idx]-1);
}
else
{
g[idx] = weight*scale*g[idx];
}
}
}
return loss;
}
friend void serialize(const loss_multiclass_log_weighted_& , std::ostream& out)
{
serialize("loss_multiclass_log_weighted_", out);
}
friend void deserialize(loss_multiclass_log_weighted_& , std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_multiclass_log_weighted_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_multiclass_log_weighted_.");
}
friend std::ostream& operator<<(std::ostream& out, const loss_multiclass_log_weighted_& )
{
out << "loss_multiclass_log_weighted";
return out;
}
friend void to_xml(const loss_multiclass_log_weighted_& /*item*/, std::ostream& out)
{
out << "<loss_multiclass_log_weighted/>";
}
};
template <typename SUBNET>
using loss_multiclass_log_weighted = add_loss_layer<loss_multiclass_log_weighted_, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_multimulticlass_log_
{
public:
loss_multimulticlass_log_ () = default;
loss_multimulticlass_log_ (
const std::map<std::string,std::vector<std::string>>& labels
)
{
for (auto& l : labels)
{
possible_labels[l.first] = std::make_shared<decltype(l.second)>(l.second);
DLIB_CASSERT(l.second.size() >= 2, "Each classifier must have at least two possible labels.");
for (size_t i = 0; i < l.second.size(); ++i)
{
label_idx_lookup[l.first][l.second[i]] = i;
++total_num_labels;
}
}
}
unsigned long number_of_labels() const { return total_num_labels; }
unsigned long number_of_classifiers() const { return possible_labels.size(); }
std::map<std::string,std::vector<std::string>> get_labels (
) const
{
std::map<std::string,std::vector<std::string>> info;
for (auto& i : possible_labels)
{
for (auto& label : *i.second)
info[i.first].emplace_back(label);
}
return info;
}
class classifier_output
{
public:
classifier_output() = default;
size_t num_classes() const { return class_probs.size(); }
double probability_of_class (
size_t i
) const
{
DLIB_CASSERT(i < num_classes());
return class_probs(i);
}
const std::string& label(
size_t i
) const
{
DLIB_CASSERT(i < num_classes());
return (*_labels)[i];
}
operator std::string(
) const
{
DLIB_CASSERT(num_classes() != 0);
return (*_labels)[index_of_max(class_probs)];
}
friend std::ostream& operator<< (std::ostream& out, const classifier_output& item)
{
DLIB_ASSERT(item.num_classes() != 0);
out << static_cast<std::string>(item);
return out;
}
private:
friend class loss_multimulticlass_log_;
template <typename EXP>
classifier_output(
const matrix_exp<EXP>& class_probs,
const std::shared_ptr<std::vector<std::string>>& _labels
) :
class_probs(class_probs),
_labels(_labels)
{
}
matrix<float,1,0> class_probs;
std::shared_ptr<std::vector<std::string>> _labels;
};
typedef std::map<std::string,std::string> training_label_type;
typedef std::map<std::string,classifier_output> output_label_type;
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter_begin
) const
{
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1 );
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(number_of_labels() != 0, "You must give the loss_multimulticlass_log_'s constructor label data before you can use it!");
DLIB_CASSERT(output_tensor.k() == (long)number_of_labels(), "The output tensor must have " << number_of_labels() << " channels.");
long k_offset = 0;
for (auto& l : possible_labels)
{
auto iter = iter_begin;
const std::string& classifier_name = l.first;
const auto& labels = (*l.second);
scratch.set_size(output_tensor.num_samples(), labels.size());
tt::copy_tensor(false, scratch, 0, output_tensor, k_offset, labels.size());
tt::softmax(scratch, scratch);
for (long i = 0; i < scratch.num_samples(); ++i)
(*iter++)[classifier_name] = classifier_output(rowm(mat(scratch),i), l.second);
k_offset += labels.size();
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth_begin,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1);
DLIB_CASSERT(grad.nr() == 1 &&
grad.nc() == 1);
DLIB_CASSERT(number_of_labels() != 0, "You must give the loss_multimulticlass_log_'s constructor label data before you can use it!");
DLIB_CASSERT(output_tensor.k() == (long)number_of_labels(), "The output tensor must have " << number_of_labels() << " channels.");
// The loss we output is the average loss over the mini-batch.
const double scale = 1.0/output_tensor.num_samples();
double loss = 0;
long k_offset = 0;
for (auto& l : label_idx_lookup)
{
const std::string& classifier_name = l.first;
const auto& int_labels = l.second;
scratch.set_size(output_tensor.num_samples(), int_labels.size());
tt::copy_tensor(false, scratch, 0, output_tensor, k_offset, int_labels.size());
tt::softmax(scratch, scratch);
auto truth = truth_begin;
float* g = scratch.host();
for (long i = 0; i < scratch.num_samples(); ++i)
{
const long y = int_labels.at(truth->at(classifier_name));
++truth;
for (long k = 0; k < scratch.k(); ++k)
{
const unsigned long idx = i*scratch.k()+k;
if (k == y)
{
loss += scale*-std::log(g[idx]);
g[idx] = scale*(g[idx]-1);
}
else
{
g[idx] = scale*g[idx];
}
}
}
tt::copy_tensor(false, grad, k_offset, scratch, 0, int_labels.size());
k_offset += int_labels.size();
}
return loss;
}
friend void serialize(const loss_multimulticlass_log_& item, std::ostream& out)
{
serialize("loss_multimulticlass_log_", out);
serialize(item.get_labels(), out);
}
friend void deserialize(loss_multimulticlass_log_& item, std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_multimulticlass_log_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_multimulticlass_log_.");
std::map<std::string,std::vector<std::string>> info;
deserialize(info, in);
item = loss_multimulticlass_log_(info);
}
friend std::ostream& operator<<(std::ostream& out, const loss_multimulticlass_log_& item)
{
out << "loss_multimulticlass_log, labels={";
for (auto i = item.possible_labels.begin(); i != item.possible_labels.end(); )
{
auto& category = i->first;
auto& labels = *(i->second);
out << category << ":(";
for (size_t j = 0; j < labels.size(); ++j)
{
out << labels[j];
if (j+1 < labels.size())
out << ",";
}
out << ")";
if (++i != item.possible_labels.end())
out << ", ";
}
out << "}";
return out;
}
friend void to_xml(const loss_multimulticlass_log_& item, std::ostream& out)
{
out << "<loss_multimulticlass_log>\n";
out << item;
out << "\n</loss_multimulticlass_log>";
}
private:
std::map<std::string,std::shared_ptr<std::vector<std::string>>> possible_labels;
unsigned long total_num_labels = 0;
// We make it true that: possible_labels[classifier][label_idx_lookup[classifier][label]] == label
std::map<std::string, std::map<std::string, size_t>> label_idx_lookup;
// Scratch doesn't logically contribute to the state of this object. It's just
// temporary scratch space used by this class.
mutable resizable_tensor scratch;
};
template <typename SUBNET>
using loss_multimulticlass_log = add_loss_layer<loss_multimulticlass_log_, SUBNET>;
inline bool operator== (const std::string& lhs, const loss_multimulticlass_log_::classifier_output& rhs)
{ return lhs == static_cast<const std::string&>(rhs); }
inline bool operator== (const loss_multimulticlass_log_::classifier_output& lhs, const std::string& rhs)
{ return rhs == static_cast<const std::string&>(lhs); }
// ----------------------------------------------------------------------------------------
class loss_multibinary_log_
{
public:
typedef std::vector<float> training_label_type;
typedef std::vector<float> output_label_type;
loss_multibinary_log_() = default;
loss_multibinary_log_(double gamma) : gamma(gamma)
{
DLIB_CASSERT(gamma >= 0);
}
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
) const
{
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(output_tensor.nr() == 1 && output_tensor.nc() == 1);
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
// Note that output_tensor.k() should match the number of labels.
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
output_label_type predictions(output_tensor.k(), 0);
for (long k = 0; k < output_tensor.k(); ++k)
{
predictions[k] = out_data[i * output_tensor.k() + k];
}
*iter++ = std::move(predictions);
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples() % sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.nr() == 1 && output_tensor.nc() == 1);
DLIB_CASSERT(grad.nr() == 1 && grad.nc() == 1);
tt::sigmoid(grad, output_tensor);
// The loss we output is the average loss over the mini-batch.
const double scale = 1.0 / output_tensor.num_samples();
double loss = 0;
float* g = grad.host();
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i, ++truth)
{
const long long num_label_categories = truth->size();
DLIB_CASSERT(output_tensor.k() == num_label_categories,
"Number of label types should match the number of output channels. "
"output_tensor.k(): " << output_tensor.k()
<< ", num_label_categories: "<< num_label_categories);
for (long k = 0; k < output_tensor.k(); ++k)
{
const float y = (*truth)[k];
DLIB_CASSERT(y != 0, "y: " << y);
const size_t idx = i * output_tensor.k() + k;
if (y > 0)
{
const float temp = log1pexp(-out_data[idx]);
const float focus = std::pow(1 - g[idx], gamma);
loss += y * scale * temp * focus;
g[idx] = y * scale * focus * (g[idx] * (gamma * temp + 1) - 1);
}
else
{
const float temp = -(-out_data[idx] - log1pexp(-out_data[idx]));
const float focus = std::pow(g[idx], gamma);
loss += -y * scale * temp * focus;
g[idx] = -y * scale * focus * g[idx] * (gamma * temp + 1);
}
}
}
return loss;
}
double get_gamma () const { return gamma; }
friend void serialize(const loss_multibinary_log_& item, std::ostream& out)
{
serialize("loss_multibinary_log_2", out);
serialize(item.gamma, out);
}
friend void deserialize(loss_multibinary_log_& item, std::istream& in)
{
std::string version;
deserialize(version, in);
if (version == "loss_multibinary_log_")
{
item.gamma = 0;
return;
}
else if (version == "loss_multibinary_log_2")
{
deserialize(item.gamma, in);
}
else
{
throw serialization_error("Unexpected version found while deserializing dlib::loss_multibinary_log_.");
}
}
friend std::ostream& operator<<(std::ostream& out, const loss_multibinary_log_& item)
{
out << "loss_multibinary_log (gamma=" << item.gamma << ")";
return out;
}
friend void to_xml(const loss_multibinary_log_& item, std::ostream& out)
{
out << "<loss_multibinary_log gamma='" << item.gamma << "'/>";
}
private:
double gamma = 0;
};
template <typename SUBNET>
using loss_multibinary_log = add_loss_layer<loss_multibinary_log_, SUBNET>;
// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------
enum class use_image_pyramid : uint8_t
{
no,
yes
};
struct mmod_options
{
public:
struct detector_window_details
{
detector_window_details() = default;
detector_window_details(unsigned long w, unsigned long h) : width(w), height(h) {}
detector_window_details(unsigned long w, unsigned long h, const std::string& l) : width(w), height(h), label(l) {}
unsigned long width = 0;
unsigned long height = 0;
std::string label;
friend inline void serialize(const detector_window_details& item, std::ostream& out)
{
int version = 2;
serialize(version, out);
serialize(item.width, out);
serialize(item.height, out);
serialize(item.label, out);
}
friend inline void deserialize(detector_window_details& item, std::istream& in)
{
int version = 0;
deserialize(version, in);
if (version != 1 && version != 2)
throw serialization_error("Unexpected version found while deserializing dlib::mmod_options::detector_window_details");
deserialize(item.width, in);
deserialize(item.height, in);
if (version == 2)
deserialize(item.label, in);
}
};
mmod_options() = default;
std::vector<detector_window_details> detector_windows;
double loss_per_false_alarm = 1;
double loss_per_missed_target = 1;
double truth_match_iou_threshold = 0.5;
test_box_overlap overlaps_nms = test_box_overlap(0.4);
test_box_overlap overlaps_ignore;
bool use_bounding_box_regression = false;
double bbr_lambda = 100;
// This field is intentionally not serialized because I want people to really think hard
// about ignoring the warnings that this suppresses.
bool be_quiet = false;
use_image_pyramid assume_image_pyramid = use_image_pyramid::yes;
mmod_options (
const std::vector<std::vector<mmod_rect>>& boxes,
const unsigned long target_size, // We want the length of the longest dimension of the detector window to be this.
const unsigned long min_target_size, // But we require that the smallest dimension of the detector window be at least this big.
const double min_detector_window_overlap_iou = 0.75
)
{
DLIB_CASSERT(0 < min_target_size && min_target_size <= target_size);
DLIB_CASSERT(0.5 < min_detector_window_overlap_iou && min_detector_window_overlap_iou < 1);
// Figure out what detector windows we will need.
for (auto& label : get_labels(boxes))
{
for (auto ratio : find_covering_aspect_ratios(boxes, test_box_overlap(min_detector_window_overlap_iou), label))
{
double detector_width;
double detector_height;
if (ratio < 1)
{
detector_height = target_size;
detector_width = ratio*target_size;
if (detector_width < min_target_size)
{
detector_height = min_target_size/ratio;
detector_width = min_target_size;
}
}
else
{
detector_width = target_size;
detector_height = target_size/ratio;
if (detector_height < min_target_size)
{
detector_width = min_target_size*ratio;
detector_height = min_target_size;
}
}
detector_window_details p((unsigned long)std::round(detector_width), (unsigned long)std::round(detector_height), label);
detector_windows.push_back(p);
}
}
DLIB_CASSERT(detector_windows.size() != 0, "You can't call mmod_options's constructor with a set of boxes that is empty (or only contains ignored boxes).");
set_overlap_nms(boxes);
}
mmod_options(
use_image_pyramid assume_image_pyramid,
const std::vector<std::vector<mmod_rect>>& boxes,
const double min_detector_window_overlap_iou = 0.75
)
: assume_image_pyramid(assume_image_pyramid)
{
DLIB_CASSERT(assume_image_pyramid == use_image_pyramid::no);
DLIB_CASSERT(0.5 < min_detector_window_overlap_iou && min_detector_window_overlap_iou < 1);
// Figure out what detector windows we will need.
for (auto& label : get_labels(boxes))
{
for (auto rectangle : find_covering_rectangles(boxes, test_box_overlap(min_detector_window_overlap_iou), label))
{
detector_windows.push_back(detector_window_details(rectangle.width(), rectangle.height(), label));
}
}
DLIB_CASSERT(detector_windows.size() != 0, "You can't call mmod_options's constructor with a set of boxes that is empty (or only contains ignored boxes).");
set_overlap_nms(boxes);
}
private:
void set_overlap_nms(const std::vector<std::vector<mmod_rect>>& boxes)
{
// Convert from mmod_rect to rectangle so we can call
// find_tight_overlap_tester().
std::vector<std::vector<rectangle>> temp;
for (auto&& bi : boxes)
{
std::vector<rectangle> rtemp;
for (auto&& b : bi)
{
if (b.ignore)
continue;
rtemp.push_back(b.rect);
}
temp.push_back(std::move(rtemp));
}
overlaps_nms = find_tight_overlap_tester(temp);
// Relax the non-max-suppression a little so that it doesn't accidentally make
// it impossible for the detector to output boxes matching the training data.
// This could be a problem with the tightest possible nms test since there is
// some small variability in how boxes get positioned between the training data
// and the coordinate system used by the detector when it runs. So relaxing it
// here takes care of that.
auto iou_thresh = advance_toward_1(overlaps_nms.get_iou_thresh());
auto percent_covered_thresh = advance_toward_1(overlaps_nms.get_percent_covered_thresh());
overlaps_nms = test_box_overlap(iou_thresh, percent_covered_thresh);
}
static double advance_toward_1 (
double val
)
{
if (val < 1)
val += (1-val)*0.1;
return val;
}
static size_t count_overlaps (
const std::vector<rectangle>& rects,
const test_box_overlap& overlaps,
const rectangle& ref_box
)
{
size_t cnt = 0;
for (auto& b : rects)
{
if (overlaps(b, ref_box))
++cnt;
}
return cnt;
}
static std::vector<rectangle> find_rectangles_overlapping_all_others (
std::vector<rectangle> rects,
const test_box_overlap& overlaps
)
{
std::vector<rectangle> exemplars;
dlib::rand rnd;
while(rects.size() > 0)
{
// Pick boxes at random and see if they overlap a lot of other boxes. We will try
// 500 different boxes each iteration and select whichever hits the most others to
// add to our exemplar set.
rectangle best_ref_box;
size_t best_cnt = 0;
for (int iter = 0; iter < 500; ++iter)
{
rectangle ref_box = rects[rnd.get_random_64bit_number()%rects.size()];
size_t cnt = count_overlaps(rects, overlaps, ref_box);
if (cnt >= best_cnt)
{
best_cnt = cnt;
best_ref_box = ref_box;
}
}
// Now mark all the boxes the new ref box hit as hit.
for (size_t i = 0; i < rects.size(); ++i)
{
if (overlaps(rects[i], best_ref_box))
{
// remove box from rects so we don't hit it again later
swap(rects[i], rects.back());
rects.pop_back();
--i;
}
}
exemplars.push_back(best_ref_box);
}
return exemplars;
}
static std::set<std::string> get_labels (
const std::vector<std::vector<mmod_rect>>& rects
)
{
std::set<std::string> labels;
for (auto& rr : rects)
{
for (auto& r : rr)
labels.insert(r.label);
}
return labels;
}
static std::vector<double> find_covering_aspect_ratios (
const std::vector<std::vector<mmod_rect>>& rects,
const test_box_overlap& overlaps,
const std::string& label
)
{
std::vector<rectangle> boxes;
// Make sure all the boxes have the same size and position, so that the only thing our
// checks for overlap will care about is aspect ratio (i.e. scale and x,y position are
// ignored).
for (auto& bb : rects)
{
for (auto&& b : bb)
{
if (!b.ignore && b.label == label)
boxes.push_back(move_rect(set_rect_area(b.rect,400*400), point(0,0)));
}
}
std::vector<double> ratios;
for (auto r : find_rectangles_overlapping_all_others(boxes, overlaps))
ratios.push_back(r.width()/(double)r.height());
return ratios;
}
static std::vector<dlib::rectangle> find_covering_rectangles (
const std::vector<std::vector<mmod_rect>>& rects,
const test_box_overlap& overlaps,
const std::string& label
)
{
std::vector<rectangle> boxes;
// Make sure all the boxes have the same position, so that the we only check for
// width and height.
for (auto& bb : rects)
{
for (auto&& b : bb)
{
if (!b.ignore && b.label == label)
boxes.push_back(rectangle(b.rect.width(), b.rect.height()));
}
}
return find_rectangles_overlapping_all_others(boxes, overlaps);
}
};
inline void serialize(const mmod_options& item, std::ostream& out)
{
int version = 4;
serialize(version, out);
serialize(item.detector_windows, out);
serialize(item.loss_per_false_alarm, out);
serialize(item.loss_per_missed_target, out);
serialize(item.truth_match_iou_threshold, out);
serialize(item.overlaps_nms, out);
serialize(item.overlaps_ignore, out);
serialize(static_cast<uint8_t>(item.assume_image_pyramid), out);
serialize(item.use_bounding_box_regression, out);
serialize(item.bbr_lambda, out);
}
inline void deserialize(mmod_options& item, std::istream& in)
{
int version = 0;
deserialize(version, in);
if (!(1 <= version && version <= 4))
throw serialization_error("Unexpected version found while deserializing dlib::mmod_options");
if (version == 1)
{
unsigned long width;
unsigned long height;
deserialize(width, in);
deserialize(height, in);
item.detector_windows = {mmod_options::detector_window_details(width, height)};
}
else
{
deserialize(item.detector_windows, in);
}
deserialize(item.loss_per_false_alarm, in);
deserialize(item.loss_per_missed_target, in);
deserialize(item.truth_match_iou_threshold, in);
deserialize(item.overlaps_nms, in);
deserialize(item.overlaps_ignore, in);
item.assume_image_pyramid = use_image_pyramid::yes;
if (version >= 3)
{
uint8_t assume_image_pyramid = 0;
deserialize(assume_image_pyramid, in);
item.assume_image_pyramid = static_cast<use_image_pyramid>(assume_image_pyramid);
}
item.use_bounding_box_regression = mmod_options().use_bounding_box_regression; // use default value since this wasn't provided
item.bbr_lambda = mmod_options().bbr_lambda; // use default value since this wasn't provided
if (version >= 4)
{
deserialize(item.use_bounding_box_regression, in);
deserialize(item.bbr_lambda, in);
}
}
inline std::ostream& operator<<(std::ostream& out, const std::vector<mmod_options::detector_window_details>& detector_windows)
{
// write detector windows grouped by label
// example output: aeroplane:74x30,131x30,70x45,54x70,198x30;bicycle:70x57,32x70,70x32,51x70,128x30,30x121;car:70x36,70x60,99x30,52x70,30x83,30x114,30x200
std::map<std::string, std::deque<mmod_options::detector_window_details>> detector_windows_by_label;
for (const auto& detector_window : detector_windows)
detector_windows_by_label[detector_window.label].push_back(detector_window);
size_t label_count = 0;
for (const auto& i : detector_windows_by_label)
{
const auto& label = i.first;
const auto& detector_windows = i.second;
if (label_count++ > 0)
out << ";";
out << label << ":";
for (size_t j = 0; j < detector_windows.size(); ++j)
{
out << detector_windows[j].width << "x" << detector_windows[j].height;
if (j + 1 < detector_windows.size())
out << ",";
}
}
return out;
}
// ----------------------------------------------------------------------------------------
class loss_mmod_
{
struct intermediate_detection
{
intermediate_detection() = default;
intermediate_detection(
rectangle rect_
) : rect(rect_), rect_bbr(rect_) {}
intermediate_detection(
rectangle rect_,
double detection_confidence_,
size_t tensor_offset_,
long channel
) : rect(rect_), detection_confidence(detection_confidence_), tensor_offset(tensor_offset_), tensor_channel(channel), rect_bbr(rect_) {}
// rect is the rectangle you get without any bounding box regression. So it's
// the basic sliding window box (aka, the "anchor box").
rectangle rect;
double detection_confidence = 0;
size_t tensor_offset = 0;
long tensor_channel = 0;
// rect_bbr = rect + bounding box regression. So more accurate. Or if bbr is off then
// this is just rect. The important thing about rect_bbr is that its the
// rectangle we use for doing NMS.
drectangle rect_bbr;
size_t tensor_offset_dx = 0;
size_t tensor_offset_dy = 0;
size_t tensor_offset_dw = 0;
size_t tensor_offset_dh = 0;
bool operator<(const intermediate_detection& item) const { return detection_confidence < item.detection_confidence; }
};
public:
typedef std::vector<mmod_rect> training_label_type;
typedef std::vector<mmod_rect> output_label_type;
loss_mmod_() {}
loss_mmod_(mmod_options options_) : options(options_) {}
const mmod_options& get_options (
) const { return options; }
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter,
double adjust_threshold = 0
) const
{
const tensor& output_tensor = sub.get_output();
if (options.use_bounding_box_regression)
{
DLIB_CASSERT(output_tensor.k() == (long)options.detector_windows.size()*5);
}
else
{
DLIB_CASSERT(output_tensor.k() == (long)options.detector_windows.size());
}
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(sub.sample_expansion_factor() == 1, sub.sample_expansion_factor());
std::vector<intermediate_detection> dets_accum;
output_label_type final_dets;
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
tensor_to_dets(input_tensor, output_tensor, i, dets_accum, adjust_threshold, sub);
// Do non-max suppression
final_dets.clear();
for (unsigned long i = 0; i < dets_accum.size(); ++i)
{
if (overlaps_any_box_nms(final_dets, dets_accum[i].rect_bbr))
continue;
final_dets.push_back(mmod_rect(dets_accum[i].rect_bbr,
dets_accum[i].detection_confidence,
options.detector_windows[dets_accum[i].tensor_channel].label));
}
*iter++ = std::move(final_dets);
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
if (options.use_bounding_box_regression)
{
DLIB_CASSERT(output_tensor.k() == (long)options.detector_windows.size()*5);
}
else
{
DLIB_CASSERT(output_tensor.k() == (long)options.detector_windows.size());
}
double det_thresh_speed_adjust = 0;
// we will scale the loss so that it doesn't get really huge
const double scale = 1.0/(output_tensor.nr()*output_tensor.nc()*output_tensor.num_samples()*options.detector_windows.size());
double loss = 0;
float* g = grad.host_write_only();
for (size_t i = 0; i < grad.size(); ++i)
g[i] = 0;
const float* out_data = output_tensor.host();
std::vector<intermediate_detection> dets;
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
tensor_to_dets(input_tensor, output_tensor, i, dets, -options.loss_per_false_alarm + det_thresh_speed_adjust, sub);
const unsigned long max_num_dets = 50 + truth->size()*5;
// Prevent calls to tensor_to_dets() from running for a really long time
// due to the production of an obscene number of detections.
const unsigned long max_num_initial_dets = max_num_dets*100;
if (dets.size() > max_num_initial_dets)
{
det_thresh_speed_adjust = std::max(det_thresh_speed_adjust,dets[max_num_initial_dets].detection_confidence + options.loss_per_false_alarm);
}
std::vector<int> truth_idxs;
truth_idxs.reserve(truth->size());
std::unordered_map<size_t, rectangle> idx_to_truth_rect;
// The loss will measure the number of incorrect detections. A detection is
// incorrect if it doesn't hit a truth rectangle or if it is a duplicate detection
// on a truth rectangle.
loss += truth->size()*options.loss_per_missed_target;
for (auto&& x : *truth)
{
if (!x.ignore)
{
size_t k;
point p;
if(image_rect_to_feat_coord(p, input_tensor, x, x.label, sub, k, options.assume_image_pyramid))
{
// Ignore boxes that can't be detected by the CNN.
loss -= options.loss_per_missed_target;
truth_idxs.push_back(-1);
continue;
}
const size_t idx = (k*output_tensor.nr() + p.y())*output_tensor.nc() + p.x();
const auto i = idx_to_truth_rect.find(idx);
if (i != idx_to_truth_rect.end())
{
if (!options.be_quiet)
{
// Ignore duplicate truth box in feature coordinates.
std::cout << "Warning, ignoring object. We encountered a truth rectangle located at " << x.rect;
std::cout << ", and we are ignoring it because it maps to the exact same feature coordinates ";
std::cout << "as another truth rectangle located at " << i->second << "." << std::endl;
}
loss -= options.loss_per_missed_target;
truth_idxs.push_back(-1);
continue;
}
loss -= out_data[idx];
// compute gradient
g[idx] = -scale;
truth_idxs.push_back(idx);
idx_to_truth_rect[idx] = x.rect;
}
else
{
// This box was ignored so shouldn't have been counted in the loss.
loss -= options.loss_per_missed_target;
truth_idxs.push_back(-1);
}
}
// Measure the loss augmented score for the detections which hit a truth rect.
std::vector<double> truth_score_hits(truth->size(), 0);
// keep track of which truth boxes we have hit so far.
std::vector<bool> hit_truth_table(truth->size(), false);
std::vector<intermediate_detection> final_dets;
// The point of this loop is to fill out the truth_score_hits array.
for (size_t i = 0; i < dets.size() && final_dets.size() < max_num_dets; ++i)
{
if (overlaps_any_box_nms(final_dets, dets[i].rect_bbr))
continue;
const auto& det_label = options.detector_windows[dets[i].tensor_channel].label;
const std::pair<double,unsigned int> hittruth = find_best_match(*truth, hit_truth_table, dets[i].rect, det_label);
final_dets.push_back(dets[i].rect);
const double truth_match = hittruth.first;
// if hit truth rect
if (truth_match > options.truth_match_iou_threshold)
{
// if this is the first time we have seen a detect which hit (*truth)[hittruth.second]
const double score = dets[i].detection_confidence;
if (hit_truth_table[hittruth.second] == false)
{
hit_truth_table[hittruth.second] = true;
truth_score_hits[hittruth.second] += score;
}
else
{
truth_score_hits[hittruth.second] += score + options.loss_per_false_alarm;
}
}
}
// Check if any of the truth boxes are unobtainable because the NMS is
// killing them. If so, automatically set those unobtainable boxes to
// ignore and print a warning message to the user.
for (size_t i = 0; i < hit_truth_table.size(); ++i)
{
if (!hit_truth_table[i] && !(*truth)[i].ignore)
{
// So we didn't hit this truth box. Is that because there is
// another, different truth box, that overlaps it according to NMS?
const std::pair<double,unsigned int> hittruth = find_best_match(*truth, (*truth)[i], i);
if (hittruth.second == i || (*truth)[hittruth.second].ignore)
continue;
rectangle best_matching_truth_box = (*truth)[hittruth.second];
if (options.overlaps_nms(best_matching_truth_box, (*truth)[i]))
{
const int idx = truth_idxs[i];
if (idx != -1)
{
// We are ignoring this box so we shouldn't have counted it in the
// loss in the first place. So we subtract out the loss values we
// added for it in the code above.
loss -= options.loss_per_missed_target-out_data[idx];
g[idx] = 0;
if (!options.be_quiet)
{
std::cout << "Warning, ignoring object. We encountered a truth rectangle located at " << (*truth)[i].rect;
std::cout << " that is suppressed by non-max-suppression ";
std::cout << "because it is overlapped by another truth rectangle located at " << best_matching_truth_box
<< " (IoU:"<< box_intersection_over_union(best_matching_truth_box,(*truth)[i]) <<", Percent covered:"
<< box_percent_covered(best_matching_truth_box,(*truth)[i]) << ")." << std::endl;
}
}
}
}
}
hit_truth_table.assign(hit_truth_table.size(), false);
final_dets.clear();
// Now figure out which detections jointly maximize the loss and detection score sum. We
// need to take into account the fact that allowing a true detection in the output, while
// initially reducing the loss, may allow us to increase the loss later with many duplicate
// detections.
for (unsigned long i = 0; i < dets.size() && final_dets.size() < max_num_dets; ++i)
{
if (overlaps_any_box_nms(final_dets, dets[i].rect_bbr))
continue;
const auto& det_label = options.detector_windows[dets[i].tensor_channel].label;
const std::pair<double,unsigned int> hittruth = find_best_match(*truth, hit_truth_table, dets[i].rect, det_label);
const double truth_match = hittruth.first;
if (truth_match > options.truth_match_iou_threshold)
{
if (truth_score_hits[hittruth.second] > options.loss_per_missed_target)
{
if (!hit_truth_table[hittruth.second])
{
hit_truth_table[hittruth.second] = true;
final_dets.push_back(dets[i]);
loss -= options.loss_per_missed_target;
// Now account for BBR loss and gradient if appropriate.
if (options.use_bounding_box_regression)
{
double dx = out_data[dets[i].tensor_offset_dx];
double dy = out_data[dets[i].tensor_offset_dy];
double dw = out_data[dets[i].tensor_offset_dw];
double dh = out_data[dets[i].tensor_offset_dh];
dpoint p = dcenter(dets[i].rect);
double w = dets[i].rect.width()-1;
double h = dets[i].rect.height()-1;
drectangle truth_box = (*truth)[hittruth.second].rect;
dpoint p_truth = dcenter(truth_box);
DLIB_CASSERT(w > 0);
DLIB_CASSERT(h > 0);
double target_dx = (p_truth.x() - p.x())/w;
double target_dy = (p_truth.y() - p.y())/h;
double target_dw = std::log((truth_box.width()-1)/w);
double target_dh = std::log((truth_box.height()-1)/h);
// compute smoothed L1 loss on BBR outputs. This loss
// is just the MSE loss when the loss is small and L1
// when large.
dx = dx-target_dx;
dy = dy-target_dy;
dw = dw-target_dw;
dh = dh-target_dh;
// use smoothed L1
double ldx = std::abs(dx)<1 ? 0.5*dx*dx : std::abs(dx)-0.5;
double ldy = std::abs(dy)<1 ? 0.5*dy*dy : std::abs(dy)-0.5;
double ldw = std::abs(dw)<1 ? 0.5*dw*dw : std::abs(dw)-0.5;
double ldh = std::abs(dh)<1 ? 0.5*dh*dh : std::abs(dh)-0.5;
loss += options.bbr_lambda*(ldx + ldy + ldw + ldh);
// now compute the derivatives of the smoothed L1 loss
ldx = put_in_range(-1,1, dx);
ldy = put_in_range(-1,1, dy);
ldw = put_in_range(-1,1, dw);
ldh = put_in_range(-1,1, dh);
// also smoothed L1 gradient goes to gradient output
g[dets[i].tensor_offset_dx] += scale*options.bbr_lambda*ldx;
g[dets[i].tensor_offset_dy] += scale*options.bbr_lambda*ldy;
g[dets[i].tensor_offset_dw] += scale*options.bbr_lambda*ldw;
g[dets[i].tensor_offset_dh] += scale*options.bbr_lambda*ldh;
}
}
else
{
final_dets.push_back(dets[i]);
loss += options.loss_per_false_alarm;
}
}
}
else if (!overlaps_ignore_box(*truth, dets[i].rect))
{
// didn't hit anything
final_dets.push_back(dets[i]);
loss += options.loss_per_false_alarm;
}
}
for (auto&& x : final_dets)
{
loss += out_data[x.tensor_offset];
g[x.tensor_offset] += scale;
}
++truth;
g += output_tensor.k()*output_tensor.nr()*output_tensor.nc();
out_data += output_tensor.k()*output_tensor.nr()*output_tensor.nc();
} // END for (long i = 0; i < output_tensor.num_samples(); ++i)
// Here we scale the loss so that it's roughly equal to the number of mistakes
// in an image. Note that this scaling is different than the scaling we
// applied to the gradient but it doesn't matter since the loss value isn't
// used to update parameters. It's used only for display and to check if we
// have converged. So it doesn't matter that they are scaled differently and
// this way the loss that is displayed is readily interpretable to the user.
return loss/output_tensor.num_samples();
}
friend void serialize(const loss_mmod_& item, std::ostream& out)
{
serialize("loss_mmod_", out);
serialize(item.options, out);
}
friend void deserialize(loss_mmod_& item, std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_mmod_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_mmod_.");
deserialize(item.options, in);
}
friend std::ostream& operator<<(std::ostream& out, const loss_mmod_& item)
{
out << "loss_mmod\t (";
auto& opts = item.options;
out << "detector_windows:(" << opts.detector_windows << ")";
out << ", loss per FA:" << opts.loss_per_false_alarm;
out << ", loss per miss:" << opts.loss_per_missed_target;
out << ", truth match IOU thresh:" << opts.truth_match_iou_threshold;
out << ", use_bounding_box_regression:" << opts.use_bounding_box_regression;
if (opts.use_bounding_box_regression)
out << ", bbr_lambda:" << opts.bbr_lambda;
out << ", overlaps_nms:("<<opts.overlaps_nms.get_iou_thresh()<<","<<opts.overlaps_nms.get_percent_covered_thresh()<<")";
out << ", overlaps_ignore:("<<opts.overlaps_ignore.get_iou_thresh()<<","<<opts.overlaps_ignore.get_percent_covered_thresh()<<")";
out << ")";
return out;
}
friend void to_xml(const loss_mmod_& /*item*/, std::ostream& out)
{
// TODO, add options fields
out << "<loss_mmod/>";
}
private:
template <typename net_type>
void tensor_to_dets (
const tensor& input_tensor,
const tensor& output_tensor,
long i,
std::vector<intermediate_detection>& dets_accum,
double adjust_threshold,
const net_type& net
) const
{
DLIB_CASSERT(net.sample_expansion_factor() == 1,net.sample_expansion_factor());
if (options.use_bounding_box_regression)
{
DLIB_CASSERT(output_tensor.k() == (long)options.detector_windows.size()*5);
}
else
{
DLIB_CASSERT(output_tensor.k() == (long)options.detector_windows.size());
}
const float* out_data = output_tensor.host() + output_tensor.k()*output_tensor.nr()*output_tensor.nc()*i;
// scan the final layer and output the positive scoring locations
dets_accum.clear();
for (long k = 0; k < (long)options.detector_windows.size(); ++k)
{
for (long r = 0; r < output_tensor.nr(); ++r)
{
for (long c = 0; c < output_tensor.nc(); ++c)
{
double score = out_data[(k*output_tensor.nr() + r)*output_tensor.nc() + c];
if (score > adjust_threshold)
{
dpoint p = output_tensor_to_input_tensor(net, point(c,r));
drectangle rect = centered_drect(p, options.detector_windows[k].width, options.detector_windows[k].height);
rect = input_layer(net).tensor_space_to_image_space(input_tensor,rect);
dets_accum.push_back(intermediate_detection(rect, score, (k*output_tensor.nr() + r)*output_tensor.nc() + c, k));
if (options.use_bounding_box_regression)
{
const auto offset = options.detector_windows.size() + k*4;
dets_accum.back().tensor_offset_dx = ((offset+0)*output_tensor.nr() + r)*output_tensor.nc() + c;
dets_accum.back().tensor_offset_dy = ((offset+1)*output_tensor.nr() + r)*output_tensor.nc() + c;
dets_accum.back().tensor_offset_dw = ((offset+2)*output_tensor.nr() + r)*output_tensor.nc() + c;
dets_accum.back().tensor_offset_dh = ((offset+3)*output_tensor.nr() + r)*output_tensor.nc() + c;
// apply BBR to dets_accum.back()
double dx = out_data[dets_accum.back().tensor_offset_dx];
double dy = out_data[dets_accum.back().tensor_offset_dy];
double dw = out_data[dets_accum.back().tensor_offset_dw];
double dh = out_data[dets_accum.back().tensor_offset_dh];
dw = std::exp(dw);
dh = std::exp(dh);
double w = rect.width()-1;
double h = rect.height()-1;
rect = translate_rect(rect, dpoint(dx*w,dy*h));
rect = centered_drect(rect, w*dw+1, h*dh+1);
dets_accum.back().rect_bbr = rect;
}
}
}
}
}
std::sort(dets_accum.rbegin(), dets_accum.rend());
}
size_t find_best_detection_window (
rectangle rect,
const std::string& label,
use_image_pyramid assume_image_pyramid
) const
{
if (assume_image_pyramid == use_image_pyramid::yes)
{
rect = move_rect(set_rect_area(rect, 400*400), point(0,0));
}
else
{
rect = rectangle(rect.width(), rect.height());
}
// Figure out which detection window in options.detector_windows is most similar to rect
// (in terms of aspect ratio, if assume_image_pyramid == use_image_pyramid::yes).
size_t best_i = 0;
double best_ratio_diff = -std::numeric_limits<double>::infinity();
for (size_t i = 0; i < options.detector_windows.size(); ++i)
{
if (options.detector_windows[i].label != label)
continue;
rectangle det_window;
if (options.assume_image_pyramid == use_image_pyramid::yes)
{
det_window = centered_rect(point(0,0), options.detector_windows[i].width, options.detector_windows[i].height);
det_window = move_rect(set_rect_area(det_window, 400*400), point(0,0));
}
else
{
det_window = rectangle(options.detector_windows[i].width, options.detector_windows[i].height);
}
double iou = box_intersection_over_union(rect, det_window);
if (iou > best_ratio_diff)
{
best_ratio_diff = iou;
best_i = i;
}
}
return best_i;
}
template <typename net_type>
bool image_rect_to_feat_coord (
point& tensor_p,
const tensor& input_tensor,
const rectangle& rect,
const std::string& label,
const net_type& net,
size_t& det_idx,
use_image_pyramid assume_image_pyramid
) const
{
using namespace std;
if (!input_layer(net).image_contained_point(input_tensor,center(rect)))
{
std::ostringstream sout;
sout << "Encountered a truth rectangle located at " << rect << " that is outside the image." << endl;
sout << "The center of each truth rectangle must be within the image." << endl;
throw impossible_labeling_error(sout.str());
}
det_idx = find_best_detection_window(rect,label,assume_image_pyramid);
double scale = 1.0;
if (options.assume_image_pyramid == use_image_pyramid::yes)
{
// Compute the scale we need to be at to get from rect to our detection window.
// Note that we compute the scale as the max of two numbers. It doesn't
// actually matter which one we pick, because if they are very different then
// it means the box can't be matched by the sliding window. But picking the
// max causes the right error message to be selected in the logic below.
scale = std::max(options.detector_windows[det_idx].width/(double)rect.width(), options.detector_windows[det_idx].height/(double)rect.height());
}
else
{
// We don't want invariance to scale.
scale = 1.0;
}
const rectangle mapped_rect = input_layer(net).image_space_to_tensor_space(input_tensor, std::min(1.0,scale), rect);
// compute the detection window that we would use at this position.
tensor_p = center(mapped_rect);
rectangle det_window = centered_rect(tensor_p, options.detector_windows[det_idx].width,options.detector_windows[det_idx].height);
det_window = input_layer(net).tensor_space_to_image_space(input_tensor, det_window);
// make sure the rect can actually be represented by the image pyramid we are
// using.
if (box_intersection_over_union(rect, det_window) <= options.truth_match_iou_threshold)
{
std::cout << "Warning, ignoring object. We encountered a truth rectangle with a width and height of " << rect.width() << " and " << rect.height() << ". ";
std::cout << "The image pyramid and sliding windows can't output a rectangle of this shape. ";
const double detector_area = options.detector_windows[det_idx].width*options.detector_windows[det_idx].height;
if (mapped_rect.area()/detector_area <= options.truth_match_iou_threshold)
{
std::cout << "This is because the rectangle is smaller than the best matching detection window, which has a width ";
std::cout << "and height of " << options.detector_windows[det_idx].width << " and " << options.detector_windows[det_idx].height << "." << std::endl;
}
else
{
std::cout << "This is either because (1) the final layer's features have too large of a stride across the image, limiting the possible locations the sliding window can search ";
std::cout << "or (2) because the rectangle's aspect ratio is too different from the best matching detection window, ";
std::cout << "which has a width and height of " << options.detector_windows[det_idx].width << " and " << options.detector_windows[det_idx].height << "." << std::endl;
}
return true;
}
// now map through the CNN to the output layer.
tensor_p = input_tensor_to_output_tensor(net,tensor_p);
const tensor& output_tensor = net.get_output();
if (!get_rect(output_tensor).contains(tensor_p))
{
std::cout << "Warning, ignoring object. We encountered a truth rectangle located at " << rect << " that is too close to the edge ";
std::cout << "of the image to be captured by the CNN features." << std::endl;
return true;
}
return false;
}
bool overlaps_ignore_box (
const std::vector<mmod_rect>& boxes,
const rectangle& rect
) const
{
for (auto&& b : boxes)
{
if (b.ignore && options.overlaps_ignore(b, rect))
return true;
}
return false;
}
std::pair<double,unsigned int> find_best_match(
const std::vector<mmod_rect>& boxes,
const std::vector<bool>& hit_truth_table,
const rectangle& rect,
const std::string& label
) const
{
double match = 0;
unsigned int best_idx = 0;
for (int allow_duplicate_hit = 0; allow_duplicate_hit <= 1 && match == 0; ++allow_duplicate_hit)
{
for (unsigned long i = 0; i < boxes.size(); ++i)
{
if (boxes[i].ignore || boxes[i].label != label)
continue;
if (!allow_duplicate_hit && hit_truth_table[i])
continue;
const double new_match = box_intersection_over_union(rect, boxes[i]);
if (new_match > match)
{
match = new_match;
best_idx = i;
}
}
}
return std::make_pair(match,best_idx);
}
std::pair<double,unsigned int> find_best_match(
const std::vector<mmod_rect>& boxes,
const rectangle& rect,
const size_t excluded_idx
) const
{
double match = 0;
unsigned int best_idx = 0;
for (unsigned long i = 0; i < boxes.size(); ++i)
{
if (boxes[i].ignore || excluded_idx == i)
continue;
const double new_match = box_intersection_over_union(rect, boxes[i]);
if (new_match > match)
{
match = new_match;
best_idx = i;
}
}
return std::make_pair(match,best_idx);
}
template <typename T>
inline bool overlaps_any_box_nms (
const std::vector<T>& rects,
const rectangle& rect
) const
{
for (auto&& r : rects)
{
if (options.overlaps_nms(r.rect, rect))
return true;
}
return false;
}
mmod_options options;
};
template <typename SUBNET>
using loss_mmod = add_loss_layer<loss_mmod_, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_metric_
{
public:
typedef unsigned long training_label_type;
typedef matrix<float,0,1> output_label_type;
loss_metric_() = default;
loss_metric_(
float margin_,
float dist_thresh_
) : margin(margin_), dist_thresh(dist_thresh_)
{
DLIB_CASSERT(margin_ > 0);
DLIB_CASSERT(dist_thresh_ > 0);
}
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
) const
{
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1);
const float* p = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
*iter = mat(p,output_tensor.k(),1);
++iter;
p += output_tensor.k();
}
}
float get_margin() const { return margin; }
float get_distance_threshold() const { return dist_thresh; }
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1);
DLIB_CASSERT(grad.nr() == 1 &&
grad.nc() == 1);
temp.set_size(output_tensor.num_samples(), output_tensor.num_samples());
grad_mul.copy_size(temp);
tt::gemm(0, temp, 1, output_tensor, false, output_tensor, true);
std::vector<double> temp_threshs;
const float* d = temp.host();
double loss = 0;
double num_pos_samps = 0.0001;
double num_neg_samps = 0.0001;
for (long r = 0; r < temp.num_samples(); ++r)
{
auto xx = d[r*temp.num_samples() + r];
const auto x_label = *(truth + r);
for (long c = r+1; c < temp.num_samples(); ++c)
{
const auto y_label = *(truth + c);
if (x_label == y_label)
{
++num_pos_samps;
}
else
{
++num_neg_samps;
// Figure out what distance threshold, when applied to the negative pairs,
// causes there to be an equal number of positive and negative pairs.
auto yy = d[c*temp.num_samples() + c];
auto xy = d[r*temp.num_samples() + c];
// compute the distance between x and y samples.
auto d2 = xx + yy - 2*xy;
if (d2 < 0)
d2 = 0;
temp_threshs.push_back(d2);
}
}
}
// The whole objective function is multiplied by this to scale the loss
// relative to the number of things in the mini-batch.
const double scale = 0.5/num_pos_samps;
DLIB_CASSERT(num_pos_samps>=1, "Make sure each mini-batch contains both positive pairs and negative pairs");
DLIB_CASSERT(num_neg_samps>=1, "Make sure each mini-batch contains both positive pairs and negative pairs");
std::sort(temp_threshs.begin(), temp_threshs.end());
const float neg_thresh = std::sqrt(temp_threshs[std::min(num_pos_samps,num_neg_samps)-1]);
// loop over all the pairs of training samples and compute the loss and
// gradients. Note that we only use the hardest negative pairs and that in
// particular we pick the number of negative pairs equal to the number of
// positive pairs so everything is balanced.
float* gm = grad_mul.host();
for (long r = 0; r < temp.num_samples(); ++r)
{
gm[r*temp.num_samples() + r] = 0;
const auto x_label = *(truth + r);
auto xx = d[r*temp.num_samples() + r];
for (long c = 0; c < temp.num_samples(); ++c)
{
if (r==c)
continue;
const auto y_label = *(truth + c);
auto yy = d[c*temp.num_samples() + c];
auto xy = d[r*temp.num_samples() + c];
// compute the distance between x and y samples.
auto d2 = xx + yy - 2*xy;
if (d2 <= 0)
d2 = 0;
else
d2 = std::sqrt(d2);
// It should be noted that the derivative of length(x-y) with respect
// to the x vector is the unit vector (x-y)/length(x-y). If you stare
// at the code below long enough you will see that it's just an
// application of this formula.
if (x_label == y_label)
{
// Things with the same label should have distances < dist_thresh between
// them. If not then we experience non-zero loss.
if (d2 < dist_thresh-margin)
{
gm[r*temp.num_samples() + c] = 0;
}
else
{
loss += scale*(d2 - (dist_thresh-margin));
gm[r*temp.num_samples() + r] += scale/d2;
gm[r*temp.num_samples() + c] = -scale/d2;
}
}
else
{
// Things with different labels should have distances > dist_thresh between
// them. If not then we experience non-zero loss.
if (d2 > dist_thresh+margin || d2 > neg_thresh)
{
gm[r*temp.num_samples() + c] = 0;
}
else
{
loss += scale*((dist_thresh+margin) - d2);
// don't divide by zero (or a really small number)
d2 = std::max(d2, 0.001f);
gm[r*temp.num_samples() + r] -= scale/d2;
gm[r*temp.num_samples() + c] = scale/d2;
}
}
}
}
tt::gemm(0, grad, 1, grad_mul, false, output_tensor, false);
return loss;
}
friend void serialize(const loss_metric_& item, std::ostream& out)
{
serialize("loss_metric_2", out);
serialize(item.margin, out);
serialize(item.dist_thresh, out);
}
friend void deserialize(loss_metric_& item, std::istream& in)
{
std::string version;
deserialize(version, in);
if (version == "loss_metric_")
{
// These values used to be hard coded, so for this version of the metric
// learning loss we just use these values.
item.margin = 0.1f;
item.dist_thresh = 0.75f;
return;
}
else if (version == "loss_metric_2")
{
deserialize(item.margin, in);
deserialize(item.dist_thresh, in);
}
else
{
throw serialization_error("Unexpected version found while deserializing dlib::loss_metric_. Instead found " + version);
}
}
friend std::ostream& operator<<(std::ostream& out, const loss_metric_& item )
{
out << "loss_metric (margin="<<item.margin<<", distance_threshold="<<item.dist_thresh<<")";
return out;
}
friend void to_xml(const loss_metric_& item, std::ostream& out)
{
out << "<loss_metric margin='"<<item.margin<<"' distance_threshold='"<<item.dist_thresh<<"'/>";
}
private:
float margin = 0.04f;
float dist_thresh = 0.6f;
// These variables are only here to avoid being reallocated over and over in
// compute_loss_value_and_gradient()
mutable resizable_tensor temp, grad_mul;
};
template <typename SUBNET>
using loss_metric = add_loss_layer<loss_metric_, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_ranking_
{
public:
typedef float training_label_type; // nominally +1/-1
typedef float output_label_type; // ranking score
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
) const
{
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1 &&
output_tensor.k() == 1);
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
*iter++ = out_data[i];
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1 &&
output_tensor.k() == 1);
DLIB_CASSERT(grad.nr() == 1 &&
grad.nc() == 1 &&
grad.k() == 1);
std::vector<double> rel_scores;
std::vector<double> nonrel_scores;
std::vector<long> rel_idx, nonrel_idx;
const float* out_data = output_tensor.host();
float* g = grad.host_write_only();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
const float y = *truth++;
if (y > 0)
{
rel_scores.push_back(out_data[i]-y);
rel_idx.push_back(i);
}
else if (y < 0)
{
nonrel_scores.push_back(out_data[i]-y);
nonrel_idx.push_back(i);
}
else
{
g[i] = 0;
}
}
std::vector<unsigned long> rel_counts;
std::vector<unsigned long> nonrel_counts;
count_ranking_inversions(rel_scores, nonrel_scores, rel_counts, nonrel_counts);
const unsigned long total_pairs = rel_scores.size()*nonrel_scores.size();
DLIB_CASSERT(total_pairs > 0, "You can't give a ranking mini-batch that contains only one class. Both classes must be represented.");
const double scale = 1.0/total_pairs;
double loss = 0;
for (unsigned long k = 0; k < rel_counts.size(); ++k)
{
loss -= rel_counts[k]*rel_scores[k];
g[rel_idx[k]] = -1.0*rel_counts[k]*scale;
}
for (unsigned long k = 0; k < nonrel_counts.size(); ++k)
{
loss += nonrel_counts[k]*nonrel_scores[k];
g[nonrel_idx[k]] = nonrel_counts[k]*scale;
}
return loss*scale;
}
friend void serialize(const loss_ranking_& , std::ostream& out)
{
serialize("loss_ranking_", out);
}
friend void deserialize(loss_ranking_& , std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_ranking_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_ranking_.");
}
friend std::ostream& operator<<(std::ostream& out, const loss_ranking_& )
{
out << "loss_ranking";
return out;
}
friend void to_xml(const loss_ranking_& /*item*/, std::ostream& out)
{
out << "<loss_ranking/>";
}
};
template <typename SUBNET>
using loss_ranking = add_loss_layer<loss_ranking_, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_mean_squared_
{
public:
typedef float training_label_type;
typedef float output_label_type;
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
) const
{
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1 &&
output_tensor.k() == 1);
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
*iter++ = out_data[i];
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1 &&
output_tensor.k() == 1);
DLIB_CASSERT(grad.nr() == 1 &&
grad.nc() == 1 &&
grad.k() == 1);
// The loss we output is the average loss over the mini-batch.
const double scale = 1.0/output_tensor.num_samples();
double loss = 0;
float* g = grad.host_write_only();
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
const float y = *truth++;
const float temp1 = y - out_data[i];
const float temp2 = scale*temp1;
loss += temp2*temp1;
g[i] = -temp2;
}
return loss;
}
friend void serialize(const loss_mean_squared_& , std::ostream& out)
{
serialize("loss_mean_squared_", out);
}
friend void deserialize(loss_mean_squared_& , std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_mean_squared_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_mean_squared_.");
}
friend std::ostream& operator<<(std::ostream& out, const loss_mean_squared_& )
{
out << "loss_mean_squared";
return out;
}
friend void to_xml(const loss_mean_squared_& /*item*/, std::ostream& out)
{
out << "<loss_mean_squared/>";
}
};
template <typename SUBNET>
using loss_mean_squared = add_loss_layer<loss_mean_squared_, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_epsilon_insensitive_
{
public:
typedef float training_label_type;
typedef float output_label_type;
loss_epsilon_insensitive_() = default;
loss_epsilon_insensitive_(double eps) : eps(eps)
{
DLIB_CASSERT(eps >= 0, "You can't set a negative error epsilon.");
}
double get_epsilon () const { return eps; }
void set_epsilon(double e)
{
DLIB_CASSERT(e >= 0, "You can't set a negative error epsilon.");
eps = e;
}
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
) const
{
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1 &&
output_tensor.k() == 1);
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
*iter++ = out_data[i];
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1 &&
output_tensor.k() == 1);
DLIB_CASSERT(grad.nr() == 1 &&
grad.nc() == 1 &&
grad.k() == 1);
// The loss we output is the average loss over the mini-batch.
const double scale = 1.0/output_tensor.num_samples();
double loss = 0;
float* g = grad.host_write_only();
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
const float y = *truth++;
const float err = out_data[i]-y;
if (err > eps)
{
loss += scale*(err-eps);
g[i] = scale;
}
else if (err < -eps)
{
loss += scale*(eps-err);
g[i] = -scale;
}
}
return loss;
}
friend void serialize(const loss_epsilon_insensitive_& item, std::ostream& out)
{
serialize("loss_epsilon_insensitive_", out);
serialize(item.eps, out);
}
friend void deserialize(loss_epsilon_insensitive_& item, std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_epsilon_insensitive_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_epsilon_insensitive_.");
deserialize(item.eps, in);
}
friend std::ostream& operator<<(std::ostream& out, const loss_epsilon_insensitive_& item)
{
out << "loss_epsilon_insensitive epsilon: " << item.eps;
return out;
}
friend void to_xml(const loss_epsilon_insensitive_& item, std::ostream& out)
{
out << "<loss_epsilon_insensitive_ epsilon='" << item.eps << "'/>";
}
private:
double eps = 1;
};
template <typename SUBNET>
using loss_epsilon_insensitive = add_loss_layer<loss_epsilon_insensitive_, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_mean_squared_multioutput_
{
public:
typedef matrix<float> training_label_type;
typedef matrix<float> output_label_type;
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
) const
{
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1)
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
*iter++ = mat(out_data, output_tensor.k(), 1);
out_data += output_tensor.k();
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.nr() == 1 &&
output_tensor.nc() == 1);
DLIB_CASSERT(grad.nr() == 1 &&
grad.nc() == 1);
DLIB_CASSERT(grad.k() == output_tensor.k());
const long k = output_tensor.k();
for (long idx = 0; idx < output_tensor.num_samples(); ++idx)
{
const_label_iterator truth_matrix_ptr = (truth + idx);
DLIB_CASSERT((*truth_matrix_ptr).nr() == k &&
(*truth_matrix_ptr).nc() == 1);
}
// The loss we output is the average loss over the mini-batch.
const double scale = 1.0/output_tensor.num_samples();
double loss = 0;
float* g = grad.host_write_only();
const float* out_data = output_tensor.host();
matrix<float> ytrue;
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
ytrue = *truth++;
for (long j = 0; j < output_tensor.k(); ++j)
{
const float y = ytrue(j, 0);
const float temp1 = y - *out_data++;
const float temp2 = scale*temp1;
loss += temp2*temp1;
*g = -temp2;
++g;
}
}
return loss;
}
friend void serialize(const loss_mean_squared_multioutput_& , std::ostream& out)
{
serialize("loss_mean_squared_multioutput_", out);
}
friend void deserialize(loss_mean_squared_multioutput_& , std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_mean_squared_multioutput_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_mean_squared_.");
}
friend std::ostream& operator<<(std::ostream& out, const loss_mean_squared_multioutput_& )
{
out << "loss_mean_squared_multioutput";
return out;
}
friend void to_xml(const loss_mean_squared_multioutput_& /*item*/, std::ostream& out)
{
out << "<loss_mean_squared_multioutput/>";
}
};
template <typename SUBNET>
using loss_mean_squared_multioutput = add_loss_layer<loss_mean_squared_multioutput_, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_binary_log_per_pixel_
{
public:
typedef matrix<float> training_label_type;
typedef matrix<float> output_label_type;
template <
typename SUB_TYPE,
typename label_iterator
>
static void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
)
{
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(output_tensor.k() == 1);
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
const float* const out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i, ++iter)
{
iter->set_size(output_tensor.nr(), output_tensor.nc());
for (long r = 0; r < output_tensor.nr(); ++r)
{
for (long c = 0; c < output_tensor.nc(); ++c)
{
iter->operator()(r, c) = out_data[tensor_index(output_tensor, i, 0, r, c)];
}
}
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.k() == 1);
DLIB_CASSERT(output_tensor.nr() == grad.nr() &&
output_tensor.nc() == grad.nc() &&
output_tensor.k() == grad.k());
for (long idx = 0; idx < output_tensor.num_samples(); ++idx)
{
const_label_iterator truth_matrix_ptr = (truth + idx);
DLIB_CASSERT(truth_matrix_ptr->nr() == output_tensor.nr() &&
truth_matrix_ptr->nc() == output_tensor.nc(),
"truth size = " << truth_matrix_ptr->nr() << " x " << truth_matrix_ptr->nc() << ", "
"output size = " << output_tensor.nr() << " x " << output_tensor.nc());
}
double loss;
#ifdef DLIB_USE_CUDA
cuda_compute(truth, output_tensor, grad, loss);
#else
cpu_compute(truth, output_tensor, grad, loss);
#endif
return loss;
}
friend void serialize(const loss_binary_log_per_pixel_& , std::ostream& out)
{
serialize("loss_binary_log_per_pixel_", out);
}
friend void deserialize(loss_binary_log_per_pixel_& , std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_binary_log_per_pixel_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_binary_log_per_pixel_.");
}
friend std::ostream& operator<<(std::ostream& out, const loss_binary_log_per_pixel_& )
{
out << "loss_binary_log_per_pixel";
return out;
}
friend void to_xml(const loss_binary_log_per_pixel_& /*item*/, std::ostream& out)
{
out << "<loss_binary_log_per_pixel/>";
}
private:
#ifdef DLIB_USE_CUDA
cuda::compute_loss_binary_log_per_pixel cuda_compute;
#else
cpu::compute_loss_binary_log_per_pixel cpu_compute;
#endif
};
template <typename SUBNET>
using loss_binary_log_per_pixel = add_loss_layer<loss_binary_log_per_pixel_, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_multiclass_log_per_pixel_
{
public:
// In semantic segmentation, if you don't know the ground-truth of some pixel,
// set the label of that pixel to this value. When you do so, the pixel will be
// ignored when computing gradients.
static const uint16_t label_to_ignore = std::numeric_limits<uint16_t>::max();
// In semantic segmentation, 65535 classes ought to be enough for anybody.
typedef matrix<uint16_t> training_label_type;
typedef matrix<uint16_t> output_label_type;
template <
typename SUB_TYPE,
typename label_iterator
>
static void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
)
{
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(output_tensor.k() >= 1); // Note that output_tensor.k() should match the number of labels.
DLIB_CASSERT(output_tensor.k() < std::numeric_limits<uint16_t>::max());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
const float* const out_data = output_tensor.host();
// The index of the largest output for each element is the label.
const auto find_label = [&](long sample, long r, long c)
{
uint16_t label = 0;
float max_value = out_data[tensor_index(output_tensor, sample, 0, r, c)];
for (long k = 1; k < output_tensor.k(); ++k)
{
const float value = out_data[tensor_index(output_tensor, sample, k, r, c)];
if (value > max_value)
{
label = static_cast<uint16_t>(k);
max_value = value;
}
}
return label;
};
for (long i = 0; i < output_tensor.num_samples(); ++i, ++iter)
{
iter->set_size(output_tensor.nr(), output_tensor.nc());
for (long r = 0; r < output_tensor.nr(); ++r)
{
for (long c = 0; c < output_tensor.nc(); ++c)
{
// The index of the largest output for this element is the label.
iter->operator()(r, c) = find_label(i, r, c);
}
}
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.k() >= 1);
DLIB_CASSERT(output_tensor.k() < std::numeric_limits<uint16_t>::max());
DLIB_CASSERT(output_tensor.nr() == grad.nr() &&
output_tensor.nc() == grad.nc() &&
output_tensor.k() == grad.k());
for (long idx = 0; idx < output_tensor.num_samples(); ++idx)
{
const_label_iterator truth_matrix_ptr = (truth + idx);
DLIB_CASSERT(truth_matrix_ptr->nr() == output_tensor.nr() &&
truth_matrix_ptr->nc() == output_tensor.nc(),
"truth size = " << truth_matrix_ptr->nr() << " x " << truth_matrix_ptr->nc() << ", "
"output size = " << output_tensor.nr() << " x " << output_tensor.nc());
}
double loss;
#ifdef DLIB_USE_CUDA
cuda_compute(truth, output_tensor, grad, loss);
#else
cpu_compute(truth, output_tensor, grad, loss);
#endif
return loss;
}
friend void serialize(const loss_multiclass_log_per_pixel_& , std::ostream& out)
{
serialize("loss_multiclass_log_per_pixel_", out);
}
friend void deserialize(loss_multiclass_log_per_pixel_& , std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_multiclass_log_per_pixel_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_multiclass_log_per_pixel_.");
}
friend std::ostream& operator<<(std::ostream& out, const loss_multiclass_log_per_pixel_& )
{
out << "loss_multiclass_log_per_pixel";
return out;
}
friend void to_xml(const loss_multiclass_log_per_pixel_& /*item*/, std::ostream& out)
{
out << "<loss_multiclass_log_per_pixel/>";
}
private:
#ifdef DLIB_USE_CUDA
cuda::compute_loss_multiclass_log_per_pixel cuda_compute;
#else
cpu::compute_loss_multiclass_log_per_pixel cpu_compute;
#endif
};
template <typename SUBNET>
using loss_multiclass_log_per_pixel = add_loss_layer<loss_multiclass_log_per_pixel_, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_multiclass_log_per_pixel_weighted_
{
public:
typedef dlib::weighted_label<uint16_t> weighted_label;
typedef matrix<weighted_label> training_label_type;
typedef matrix<uint16_t> output_label_type;
template <
typename SUB_TYPE,
typename label_iterator
>
static void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
)
{
loss_multiclass_log_per_pixel_::to_label(input_tensor, sub, iter);
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.k() >= 1);
DLIB_CASSERT(output_tensor.k() < std::numeric_limits<uint16_t>::max());
DLIB_CASSERT(output_tensor.nr() == grad.nr() &&
output_tensor.nc() == grad.nc() &&
output_tensor.k() == grad.k());
for (long idx = 0; idx < output_tensor.num_samples(); ++idx)
{
const_label_iterator truth_matrix_ptr = (truth + idx);
DLIB_CASSERT(truth_matrix_ptr->nr() == output_tensor.nr() &&
truth_matrix_ptr->nc() == output_tensor.nc(),
"truth size = " << truth_matrix_ptr->nr() << " x " << truth_matrix_ptr->nc() << ", "
"output size = " << output_tensor.nr() << " x " << output_tensor.nc());
}
double loss;
#ifdef DLIB_USE_CUDA
cuda_compute(truth, output_tensor, grad, loss);
#else
cpu_compute(truth, output_tensor, grad, loss);
#endif
return loss;
}
friend void serialize(const loss_multiclass_log_per_pixel_weighted_& , std::ostream& out)
{
serialize("loss_multiclass_log_per_pixel_weighted_", out);
}
friend void deserialize(loss_multiclass_log_per_pixel_weighted_& , std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_multiclass_log_per_pixel_weighted_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_multiclass_log_per_pixel_weighted_.");
}
friend std::ostream& operator<<(std::ostream& out, const loss_multiclass_log_per_pixel_weighted_& )
{
out << "loss_multiclass_log_per_pixel_weighted";
return out;
}
friend void to_xml(const loss_multiclass_log_per_pixel_weighted_& /*item*/, std::ostream& out)
{
out << "<loss_multiclass_log_per_pixel_weighted/>";
}
private:
#ifdef DLIB_USE_CUDA
cuda::compute_loss_multiclass_log_per_pixel_weighted cuda_compute;
#else
cpu::compute_loss_multiclass_log_per_pixel_weighted cpu_compute;
#endif
};
template <typename SUBNET>
using loss_multiclass_log_per_pixel_weighted = add_loss_layer<loss_multiclass_log_per_pixel_weighted_, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_mean_squared_per_pixel_
{
public:
typedef matrix<float> training_label_type;
typedef matrix<float> output_label_type;
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
) const
{
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(output_tensor.k() == 1, "output k = " << output_tensor.k());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i, ++iter)
{
iter->set_size(output_tensor.nr(), output_tensor.nc());
for (long r = 0; r < output_tensor.nr(); ++r)
{
for (long c = 0; c < output_tensor.nc(); ++c)
{
iter->operator()(r, c) = out_data[tensor_index(output_tensor, i, 0, r, c)];
}
}
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples() % sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.k() >= 1);
DLIB_CASSERT(output_tensor.k() < std::numeric_limits<uint16_t>::max());
DLIB_CASSERT(output_tensor.nr() == grad.nr() &&
output_tensor.nc() == grad.nc() &&
output_tensor.k() == grad.k());
for (long idx = 0; idx < output_tensor.num_samples(); ++idx)
{
const_label_iterator truth_matrix_ptr = (truth + idx);
DLIB_CASSERT(truth_matrix_ptr->nr() == output_tensor.nr() &&
truth_matrix_ptr->nc() == output_tensor.nc(),
"truth size = " << truth_matrix_ptr->nr() << " x " << truth_matrix_ptr->nc() << ", "
"output size = " << output_tensor.nr() << " x " << output_tensor.nc());
}
// The loss we output is the average loss over the mini-batch, and also over each element of the matrix output.
const double scale = 1.0 / (output_tensor.num_samples() * output_tensor.nr() * output_tensor.nc());
double loss = 0;
float* const g = grad.host();
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i, ++truth)
{
for (long r = 0; r < output_tensor.nr(); ++r)
{
for (long c = 0; c < output_tensor.nc(); ++c)
{
const float y = truth->operator()(r, c);
const size_t idx = tensor_index(output_tensor, i, 0, r, c);
const float temp1 = y - out_data[idx];
const float temp2 = scale*temp1;
loss += temp2*temp1;
g[idx] = -temp2;
}
}
}
return loss;
}
friend void serialize(const loss_mean_squared_per_pixel_& , std::ostream& out)
{
serialize("loss_mean_squared_per_pixel_", out);
}
friend void deserialize(loss_mean_squared_per_pixel_& , std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_mean_squared_per_pixel_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_mean_squared_per_pixel_.");
}
friend std::ostream& operator<<(std::ostream& out, const loss_mean_squared_per_pixel_& )
{
out << "loss_mean_squared_per_pixel";
return out;
}
friend void to_xml(const loss_mean_squared_per_pixel_& /*item*/, std::ostream& out)
{
out << "<loss_mean_squared_per_pixel/>";
}
};
template <typename SUBNET>
using loss_mean_squared_per_pixel = add_loss_layer<loss_mean_squared_per_pixel_, SUBNET>;
// ----------------------------------------------------------------------------------------
template<long _num_channels>
class loss_mean_squared_per_channel_and_pixel_
{
public:
typedef std::array<matrix<float>, _num_channels> training_label_type;
typedef std::array<matrix<float>, _num_channels> output_label_type;
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
) const
{
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(output_tensor.k() == _num_channels, "output k = " << output_tensor.k());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i, ++iter)
{
for (long k = 0; k < output_tensor.k(); ++k)
{
(*iter)[k].set_size(output_tensor.nr(), output_tensor.nc());
for (long r = 0; r < output_tensor.nr(); ++r)
{
for (long c = 0; c < output_tensor.nc(); ++c)
{
(*iter)[k].operator()(r, c) = out_data[tensor_index(output_tensor, i, k, r, c)];
}
}
}
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples() % sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.k() == _num_channels);
DLIB_CASSERT(output_tensor.nr() == grad.nr() &&
output_tensor.nc() == grad.nc() &&
output_tensor.k() == grad.k());
for (long idx = 0; idx < output_tensor.num_samples(); ++idx)
{
const_label_iterator truth_matrix_ptr = (truth + idx);
DLIB_CASSERT((*truth_matrix_ptr).size() == _num_channels);
for (long k = 0; k < output_tensor.k(); ++k)
{
DLIB_CASSERT((*truth_matrix_ptr)[k].nr() == output_tensor.nr() &&
(*truth_matrix_ptr)[k].nc() == output_tensor.nc(),
"truth size = " << (*truth_matrix_ptr)[k].nr() << " x " << (*truth_matrix_ptr)[k].nc() << ", "
"output size = " << output_tensor.nr() << " x " << output_tensor.nc());
}
}
double loss;
#ifdef DLIB_USE_CUDA
cuda_compute(truth, output_tensor, grad, loss);
#else
cpu_compute(truth, output_tensor, grad, loss);
#endif
return loss;
}
friend void serialize(const loss_mean_squared_per_channel_and_pixel_& , std::ostream& out)
{
serialize("loss_mean_squared_per_channel_and_pixel_", out);
}
friend void deserialize(loss_mean_squared_per_channel_and_pixel_& , std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_mean_squared_per_channel_and_pixel_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_mean_squared_per_channel_and_pixel_.");
}
friend std::ostream& operator<<(std::ostream& out, const loss_mean_squared_per_channel_and_pixel_& )
{
out << "loss_mean_squared_per_channel_and_pixel";
return out;
}
friend void to_xml(const loss_mean_squared_per_channel_and_pixel_& /*item*/, std::ostream& out)
{
out << "<loss_mean_squared_per_channel_and_pixel/>";
}
private:
#ifdef DLIB_USE_CUDA
cuda::compute_loss_mean_squared_per_channel_and_pixel cuda_compute;
#else
cpu::compute_loss_mean_squared_per_channel_and_pixel cpu_compute;
#endif
};
template <long num_channels, typename SUBNET>
using loss_mean_squared_per_channel_and_pixel = add_loss_layer<loss_mean_squared_per_channel_and_pixel_<num_channels>, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_dot_
{
public:
typedef matrix<float,0,1> training_label_type;
typedef matrix<float,0,1> output_label_type;
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter
) const
{
const tensor& output_tensor = sub.get_output();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
for (long i = 0; i < output_tensor.num_samples(); ++i)
*iter++ = trans(rowm(mat(output_tensor),i));
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 1);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples()%sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
const long network_output_dims = output_tensor.size()/output_tensor.num_samples();
// The loss we output is the average loss over the mini-batch.
const double scale = 1.0/output_tensor.num_samples();
double loss = 0;
float* g = grad.host();
const float* out_data = output_tensor.host();
for (long i = 0; i < output_tensor.num_samples(); ++i)
{
DLIB_CASSERT(truth->size() == network_output_dims, "The network must output a vector with the same dimensionality as the training labels. "
<< "\ntruth->size(): " << truth->size()
<< "\nnetwork_output_dims: " << network_output_dims);
const float* t = &(*truth++)(0);
for (long j = 0; j < network_output_dims; ++j)
{
g[j] = -t[j]*scale;
loss -= out_data[j]*t[j];
}
g += network_output_dims;
out_data += network_output_dims;
}
return loss*scale;
}
friend void serialize(const loss_dot_& , std::ostream& out)
{
serialize("loss_dot_", out);
}
friend void deserialize(loss_dot_& , std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_dot_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_dot_.");
}
friend std::ostream& operator<<(std::ostream& out, const loss_dot_& )
{
out << "loss_dot";
return out;
}
friend void to_xml(const loss_dot_& /*item*/, std::ostream& out)
{
out << "<loss_dot/>";
}
};
template <typename SUBNET>
using loss_dot = add_loss_layer<loss_dot_, SUBNET>;
// ----------------------------------------------------------------------------------------
struct yolo_options
{
public:
struct anchor_box_details
{
anchor_box_details() = default;
anchor_box_details(unsigned long w, unsigned long h) : width(w), height(h) {}
unsigned long width = 0;
unsigned long height = 0;
friend inline void serialize(const anchor_box_details& item, std::ostream& out)
{
int version = 0;
serialize(version, out);
serialize(item.width, out);
serialize(item.height, out);
}
friend inline void deserialize(anchor_box_details& item, std::istream& in)
{
int version = 0;
deserialize(version, in);
deserialize(item.width, in);
deserialize(item.height, in);
}
};
yolo_options() = default;
template <template <typename> class TAG_TYPE>
void add_anchors(const std::vector<anchor_box_details>& boxes)
{
anchors[tag_id<TAG_TYPE>::id] = boxes;
}
// map between the stride and the anchor boxes
std::map<int, std::vector<anchor_box_details>> anchors;
std::vector<std::string> labels;
double iou_ignore_threshold = 0.7;
double iou_anchor_threshold = 1.0;
test_box_overlap overlaps_nms = test_box_overlap(0.45, 1.0);
bool classwise_nms = true;
double lambda_obj = 1.0;
double lambda_box = 1.0;
double lambda_cls = 1.0;
};
inline void serialize(const yolo_options& item, std::ostream& out)
{
int version = 1;
serialize(version, out);
serialize(item.anchors, out);
serialize(item.labels, out);
serialize(item.iou_ignore_threshold, out);
serialize(item.iou_anchor_threshold, out);
serialize(item.classwise_nms, out);
serialize(item.overlaps_nms, out);
serialize(item.lambda_obj, out);
serialize(item.lambda_box, out);
serialize(item.lambda_cls, out);
}
inline void deserialize(yolo_options& item, std::istream& in)
{
int version = 0;
deserialize(version, in);
if (version != 1)
throw serialization_error("Unexpected version found while deserializing dlib::yolo_options.");
deserialize(item.anchors, in);
deserialize(item.labels, in);
deserialize(item.iou_ignore_threshold, in);
deserialize(item.iou_anchor_threshold, in);
deserialize(item.classwise_nms, in);
deserialize(item.overlaps_nms, in);
deserialize(item.lambda_obj, in);
deserialize(item.lambda_box, in);
deserialize(item.lambda_cls, in);
}
inline std::ostream& operator<<(std::ostream& out, const std::map<int, std::vector<yolo_options::anchor_box_details>>& anchors)
{
// write anchor boxes grouped by tag id
size_t tag_count = 0;
for (const auto& i : anchors)
{
const auto& tag_id = i.first;
const auto& details = i.second;
if (tag_count++ > 0)
out << ";";
out << "tag" << tag_id << ":";
for (size_t a = 0; a < details.size(); ++a)
{
out << details[a].width << "x" << details[a].height;
if (a + 1 < details.size())
out << ",";
}
}
return out;
}
namespace impl
{
template <template <typename> class TAG_TYPE, template <typename> class... TAG_TYPES>
struct yolo_helper_impl
{
constexpr static size_t tag_count()
{
return 1 + yolo_helper_impl<TAG_TYPES...>::tag_count();
}
static void list_tags(std::ostream& out)
{
out << "tag" << tag_id<TAG_TYPE>::id << (tag_count() > 1 ? "," : "");
yolo_helper_impl<TAG_TYPES...>::list_tags(out);
}
template <typename SUBNET>
static void tensor_to_dets (
const tensor& input_tensor,
const SUBNET& sub,
const long n,
const yolo_options& options,
const double adjust_threshold,
std::vector<yolo_rect>& dets
)
{
yolo_helper_impl<TAG_TYPE>::tensor_to_dets(input_tensor, sub, n, options, adjust_threshold, dets);
yolo_helper_impl<TAG_TYPES...>::tensor_to_dets(input_tensor, sub, n, options, adjust_threshold, dets);
}
template <
typename const_label_iterator,
typename SUBNET
>
static void tensor_to_loss (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub,
const long n,
const yolo_options& options,
double& loss
)
{
yolo_helper_impl<TAG_TYPE>::tensor_to_loss(input_tensor, truth, sub, n, options, loss);
yolo_helper_impl<TAG_TYPES...>::tensor_to_loss(input_tensor, truth, sub, n, options, loss);
}
};
template <template <typename> class TAG_TYPE>
struct yolo_helper_impl<TAG_TYPE>
{
constexpr static size_t tag_count() { return 1; }
static void list_tags(std::ostream& out) { out << "tag" << tag_id<TAG_TYPE>::id; }
template <typename SUBNET>
static void tensor_to_dets (
const tensor& input_tensor,
const SUBNET& sub,
const long n,
const yolo_options& options,
const double adjust_threshold,
std::vector<yolo_rect>& dets
)
{
const auto& anchors = options.anchors.at(tag_id<TAG_TYPE>::id);
const tensor& output_tensor = layer<TAG_TYPE>(sub).get_output();
DLIB_CASSERT(static_cast<size_t>(output_tensor.k()) == anchors.size() * (options.labels.size() + 5));
const auto stride_x = static_cast<double>(input_tensor.nc()) / output_tensor.nc();
const auto stride_y = static_cast<double>(input_tensor.nr()) / output_tensor.nr();
const long num_feats = output_tensor.k() / anchors.size();
const long num_classes = num_feats - 5;
const float* const out_data = output_tensor.host();
for (size_t a = 0; a < anchors.size(); ++a)
{
const long k = a * num_feats;
for (long r = 0; r < output_tensor.nr(); ++r)
{
for (long c = 0; c < output_tensor.nc(); ++c)
{
const float obj = out_data[tensor_index(output_tensor, n, k + 4, r, c)];
if (obj > adjust_threshold)
{
const auto x = out_data[tensor_index(output_tensor, n, k + 0, r, c)] * 2.0 - 0.5;
const auto y = out_data[tensor_index(output_tensor, n, k + 1, r, c)] * 2.0 - 0.5;
const auto w = out_data[tensor_index(output_tensor, n, k + 2, r, c)];
const auto h = out_data[tensor_index(output_tensor, n, k + 3, r, c)];
yolo_rect det(centered_drect(dpoint((x + c) * stride_x, (y + r) * stride_y),
w / (1 - w) * anchors[a].width,
h / (1 - h) * anchors[a].height));
for (long i = 0; i < num_classes; ++i)
{
const float conf = obj * out_data[tensor_index(output_tensor, n, k + 5 + i, r, c)];
if (conf > adjust_threshold)
det.labels.emplace_back(conf, options.labels[i]);
}
if (!det.labels.empty())
{
std::sort(det.labels.rbegin(), det.labels.rend());
det.detection_confidence = det.labels[0].first;
det.label = det.labels[0].second;
dets.push_back(std::move(det));
}
}
}
}
}
}
template <
typename const_label_iterator,
typename SUBNET
>
static void tensor_to_loss (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub,
const long n,
const yolo_options& options,
double& loss
)
{
const tensor& output_tensor = layer<TAG_TYPE>(sub).get_output();
const auto& anchors = options.anchors.at(tag_id<TAG_TYPE>::id);
DLIB_CASSERT(static_cast<size_t>(output_tensor.k()) == anchors.size() * (options.labels.size() + 5));
const auto stride_x = static_cast<double>(input_tensor.nc()) / output_tensor.nc();
const auto stride_y = static_cast<double>(input_tensor.nr()) / output_tensor.nr();
const long num_feats = output_tensor.k() / anchors.size();
const long num_classes = num_feats - 5;
const float* const out_data = output_tensor.host();
tensor& grad = layer<TAG_TYPE>(sub).get_gradient_input();
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
const rectangle input_rect(input_tensor.nr(), input_tensor.nc());
float* g = grad.host();
// Compute the objectness loss for all grid cells
for (long r = 0; r < output_tensor.nr(); ++r)
{
for (long c = 0; c < output_tensor.nc(); ++c)
{
for (size_t a = 0; a < anchors.size(); ++a)
{
const long k = a * num_feats;
const auto x = out_data[tensor_index(output_tensor, n, k + 0, r, c)] * 2.0 - 0.5;
const auto y = out_data[tensor_index(output_tensor, n, k + 1, r, c)] * 2.0 - 0.5;
const auto w = out_data[tensor_index(output_tensor, n, k + 2, r, c)];
const auto h = out_data[tensor_index(output_tensor, n, k + 3, r, c)];
// The prediction at r, c for anchor a
const yolo_rect pred(centered_drect(dpoint((x + c) * stride_x, (y + r) * stride_y),
w / (1 - w) * anchors[a].width,
h / (1 - h) * anchors[a].height));
// Find the best IoU for all ground truth boxes
double best_iou = 0;
for (const yolo_rect& truth_box : *truth)
{
if (truth_box.ignore || !input_rect.contains(center(truth_box.rect)))
continue;
best_iou = std::max(best_iou, box_intersection_over_union(truth_box.rect, pred.rect));
}
// Incur loss for the boxes that are below a certain IoU threshold with any truth box
const auto o_idx = tensor_index(output_tensor, n, k + 4, r, c);
if (best_iou < options.iou_ignore_threshold)
g[o_idx] = options.lambda_obj * out_data[o_idx];
}
}
}
// Now find the best anchor box for each truth box
for (const yolo_rect& truth_box : *truth)
{
if (truth_box.ignore || !input_rect.contains(center(truth_box.rect)))
continue;
const dpoint t_center = dcenter(truth_box);
double best_iou = 0;
size_t best_a = 0;
size_t best_tag_id = 0;
for (const auto& item : options.anchors)
{
const auto tag_id = item.first;
const auto details = item.second;
for (size_t a = 0; a < details.size(); ++a)
{
const yolo_rect anchor(centered_drect(t_center, details[a].width, details[a].height));
const double iou = box_intersection_over_union(truth_box.rect, anchor.rect);
if (iou > best_iou)
{
best_iou = iou;
best_a = a;
best_tag_id = tag_id;
}
}
}
for (size_t a = 0; a < anchors.size(); ++a)
{
// Update best anchor if it's from the current stride, and optionally other anchors
if ((best_tag_id == tag_id<TAG_TYPE>::id && best_a == a) || options.iou_anchor_threshold < 1)
{
// do not update other anchors if they have low IoU
if (!(best_tag_id == tag_id<TAG_TYPE>::id && best_a == a))
{
const yolo_rect anchor(centered_drect(t_center, anchors[a].width, anchors[a].height));
const double iou = box_intersection_over_union(truth_box.rect, anchor.rect);
if (iou < options.iou_anchor_threshold)
continue;
}
const long c = t_center.x() / stride_x;
const long r = t_center.y() / stride_y;
const long k = a * num_feats;
// Get the truth box target values
const double tx = t_center.x() / stride_x - c;
const double ty = t_center.y() / stride_y - r;
const double tw = truth_box.rect.width() / (anchors[a].width + truth_box.rect.width());
const double th = truth_box.rect.height() / (anchors[a].height + truth_box.rect.height());
// Scale regression error according to the truth size
const double scale_box = options.lambda_box * (2 - truth_box.rect.area() / input_rect.area());
// Compute the gradient for the box coordinates
const auto x_idx = tensor_index(output_tensor, n, k + 0, r, c);
const auto y_idx = tensor_index(output_tensor, n, k + 1, r, c);
const auto w_idx = tensor_index(output_tensor, n, k + 2, r, c);
const auto h_idx = tensor_index(output_tensor, n, k + 3, r, c);
g[x_idx] = scale_box * (out_data[x_idx] * 2.0 - 0.5 - tx);
g[y_idx] = scale_box * (out_data[y_idx] * 2.0 - 0.5 - ty);
g[w_idx] = scale_box * (out_data[w_idx] - tw);
g[h_idx] = scale_box * (out_data[h_idx] - th);
// This grid cell should detect an object
const auto o_idx = tensor_index(output_tensor, n, k + 4, r, c);
g[o_idx] = options.lambda_obj * (out_data[o_idx] - 1);
// Compute the classification error
for (long i = 0; i < num_classes; ++i)
{
const auto c_idx = tensor_index(output_tensor, n, k + 5 + i, r, c);
if (truth_box.label == options.labels[i])
g[c_idx] = options.lambda_cls * (out_data[c_idx] - 1);
else
g[c_idx] = options.lambda_cls * out_data[c_idx];
}
}
}
}
// Compute the L2 loss
loss += length_squared(rowm(mat(grad), n));
}
};
}
template <template <typename> class... TAG_TYPES>
class loss_yolo_
{
static void list_tags(std::ostream& out) { impl::yolo_helper_impl<TAG_TYPES...>::list_tags(out); }
public:
typedef std::vector<yolo_rect> training_label_type;
typedef std::vector<yolo_rect> output_label_type;
constexpr static size_t tag_count() { return impl::yolo_helper_impl<TAG_TYPES...>::tag_count(); }
loss_yolo_() {};
loss_yolo_(const yolo_options& options) : options(options) { }
template <
typename SUB_TYPE,
typename label_iterator
>
void to_label (
const tensor& input_tensor,
const SUB_TYPE& sub,
label_iterator iter,
double adjust_threshold = 0.25
) const
{
DLIB_CASSERT(sub.sample_expansion_factor() == 1, sub.sample_expansion_factor());
std::vector<yolo_rect> dets_accum;
std::vector<yolo_rect> final_dets;
for (long i = 0; i < input_tensor.num_samples(); ++i)
{
dets_accum.clear();
impl::yolo_helper_impl<TAG_TYPES...>::tensor_to_dets(input_tensor, sub, i, options, adjust_threshold, dets_accum);
// Do non-max suppression
std::sort(dets_accum.rbegin(), dets_accum.rend());
final_dets.clear();
for (size_t j = 0; j < dets_accum.size(); ++j)
{
if (overlaps_any_box_nms(final_dets, dets_accum[j]))
continue;
final_dets.push_back(dets_accum[j]);
}
*iter++ = std::move(final_dets);
}
}
template <
typename const_label_iterator,
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
const_label_iterator truth,
SUBNET& sub
) const
{
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(sub.sample_expansion_factor() == 1, sub.sample_expansion_factor());
double loss = 0;
for (long i = 0; i < input_tensor.num_samples(); ++i)
{
impl::yolo_helper_impl<TAG_TYPES...>::tensor_to_loss(input_tensor, truth, sub, i, options, loss);
++truth;
}
return loss / input_tensor.num_samples();
}
const yolo_options& get_options() const { return options; }
void adjust_nms(double iou_thresh, double percent_covered_thresh = 1, bool classwise = true)
{
options.overlaps_nms = test_box_overlap(iou_thresh, percent_covered_thresh);
options.classwise_nms = classwise;
}
friend void serialize(const loss_yolo_& item, std::ostream& out)
{
serialize("loss_yolo_", out);
size_t count = tag_count();
serialize(count, out);
serialize(item.options, out);
}
friend void deserialize(loss_yolo_& item, std::istream& in)
{
std::string version;
deserialize(version, in);
if (version != "loss_yolo_")
throw serialization_error("Unexpected version found while deserializing dlib::loss_yolo_.");
size_t count = 0;
deserialize(count, in);
if (count != tag_count())
throw serialization_error("Invalid number of detection tags " + std::to_string(count) +
", while deserializing dlib::loss_yolo_, expecting " +
std::to_string(tag_count()) + " tags instead.");
deserialize(item.options, in);
}
friend std::ostream& operator<<(std::ostream& out, const loss_yolo_& item)
{
out << "loss_yolo\t (";
const auto& opts = item.options;
out << tag_count() << " output" << (tag_count() != 1 ? "s" : "") << ":(";
list_tags(out);
out << ")";
out << ", anchor_boxes:(" << opts.anchors << ")";
out << ", " << opts.labels.size() << " label" << (opts.labels.size() != 1 ? "s" : "") << ":(";
for (size_t i = 0; i < opts.labels.size(); ++i)
{
out << opts.labels[i];
if (i + 1 < opts.labels.size())
out << ",";
}
out << ")";
out << ", iou_ignore_threshold: " << opts.iou_ignore_threshold;
out << ", iou_anchor_threshold: " << opts.iou_anchor_threshold;
out << ", lambda_obj:" << opts.lambda_obj;
out << ", lambda_box:" << opts.lambda_box;
out << ", lambda_cls:" << opts.lambda_cls;
out << ", overlaps_nms:(" << opts.overlaps_nms.get_iou_thresh() << "," << opts.overlaps_nms.get_percent_covered_thresh() << ")";
out << ", classwise_nms:" << std::boolalpha << opts.classwise_nms;
out << ")";
return out;
}
friend void to_xml(const loss_yolo_& /*item*/, std::ostream& out)
{
out << "<loss_yolo/>";
}
private:
yolo_options options;
inline bool overlaps_any_box_nms (
const std::vector<yolo_rect>& boxes,
const yolo_rect& box
) const
{
for (const auto& b : boxes)
{
if (options.overlaps_nms(b.rect, box.rect))
{
if (options.classwise_nms)
{
if (b.label == box.label)
return true;
}
else
{
return true;
}
}
}
return false;
}
};
template <template <typename> class TAG_1, template <typename> class TAG_2, template <typename> class TAG_3, typename SUBNET>
using loss_yolo = add_loss_layer<loss_yolo_<TAG_1, TAG_2, TAG_3>, SUBNET>;
// ----------------------------------------------------------------------------------------
class loss_barlow_twins_
{
public:
loss_barlow_twins_() = default;
loss_barlow_twins_(float lambda) : lambda(lambda)
{
DLIB_CASSERT(lambda > 0);
}
template <
typename SUBNET
>
double compute_loss_value_and_gradient (
const tensor& input_tensor,
SUBNET& sub
) const
{
const tensor& output_tensor = sub.get_output();
tensor& grad = sub.get_gradient_input();
DLIB_CASSERT(sub.sample_expansion_factor() == 2);
DLIB_CASSERT(input_tensor.num_samples() != 0);
DLIB_CASSERT(input_tensor.num_samples() % sub.sample_expansion_factor() == 0);
DLIB_CASSERT(input_tensor.num_samples() == grad.num_samples());
DLIB_CASSERT(input_tensor.num_samples() == output_tensor.num_samples());
DLIB_CASSERT(output_tensor.nr() == 1 && output_tensor.nc() == 1);
DLIB_CASSERT(grad.nr() == 1 && grad.nc() == 1);
const auto batch_size = output_tensor.num_samples() / 2;
const auto sample_size = output_tensor.k();
const auto offset = batch_size * sample_size;
// Alias helpers to access the samples in the batch
alias_tensor split(batch_size, sample_size);
auto za = split(output_tensor);
auto zb = split(output_tensor, offset);
// Normalize both batches independently across the batch dimension
const double eps = 1e-4;
g.set_size(1, sample_size);
g = 1;
b.set_size(1, sample_size);
b = 0;
tt::batch_normalize(eps, za_norm, means_a, invstds_a, 1, rms, rvs, za, g, b);
tt::batch_normalize(eps, zb_norm, means_b, invstds_b, 1, rms, rvs, zb, g, b);
// Compute the empirical cross-correlation matrix
eccm.set_size(sample_size, sample_size);
tt::gemm(0, eccm, 1, za_norm, true, zb_norm, false);
eccm /= batch_size;
// Set sizes and setup auxiliary tensors
if (!have_same_dimensions(eccm, identity))
identity = identity_matrix<float>(sample_size);
if (!have_same_dimensions(eccm, cdiag))
cdiag.copy_size(eccm);
if (!have_same_dimensions(eccm, cdiag_1))
cdiag_1.copy_size(eccm);
if (!have_same_dimensions(eccm, off_mask))
off_mask = ones_matrix<float>(sample_size, sample_size) - identity_matrix<float>(sample_size);
if (!have_same_dimensions(eccm, off_diag))
off_diag.copy_size(eccm);
if (!have_same_dimensions(grad, grad_input))
grad_input.copy_size(grad);
if (!have_same_dimensions(g_grad, g))
g_grad.copy_size(g);
if (!have_same_dimensions(b_grad, b))
b_grad.copy_size(b);
// Loss gradient, which will be used as the input of the batch normalization gradient
auto grad_input_a = split(grad_input);
auto grad_input_b = split(grad_input, offset);
// Compute the loss: notation from http://www.matrixcalculus.org/
// A = za_norm
// B = zb_norm
// C = eccm
// D = off_mask: a mask that keeps only the elements outside the diagonal
// A diagonal matrix containing the diagonal of eccm
tt::multiply(false, cdiag, eccm, identity);
// The diagonal of eccm minus the identity matrix
tt::affine_transform(cdiag_1, cdiag, identity, 1, -1);
// diagonal term: sum((diag(A' * B) - vector(1)).^2)
// --------------------------------------------
// => d/dA = 2 * B * diag(diag(A' * B) - vector(1)) = 2 * B * diag(diag(C) - vector(1))
// => d/dB = 2 * A * diag(diag(A' * B) - vector(1)) = 2 * A * diag(diag(C) - vector(1))
tt::gemm(0, grad_input_a, 2, zb_norm, false, cdiag_1, false);
tt::gemm(0, grad_input_b, 2, za_norm, false, cdiag_1, false);
// off-diag term: sum(((A'* B) .* D).^2)
// --------------------------------
// => d/dA = 2 * B * ((B' * A) .* (D .* D)') = 2 * B * (C .* (D .* D)) = 2 * B * (C .* D)
// => d/dB = 2 * A * ((A' * B) .* (D .* D)) = 2 * A * (C .* (D .* D)) = 2 * A * (C .* D)
tt::multiply(false, off_diag, eccm, off_mask);
tt::gemm(1, grad_input_a, 2 * lambda, zb_norm, false, off_diag, false);
tt::gemm(1, grad_input_b, 2 * lambda, za_norm, false, off_diag, false);
// Compute the batch norm gradients, g and b grads are not used
auto gza = split(grad);
auto gzb = split(grad, offset);
tt::batch_normalize_gradient(eps, grad_input_a, means_a, invstds_a, za, g, gza, g_grad, b_grad);
tt::batch_normalize_gradient(eps, grad_input_b, means_b, invstds_b, zb, g, gzb, g_grad, b_grad);
// Compute the loss: MSE between eccm and the identity matrix.
// Off-diagonal terms are weighed by lambda.
const double diagonal_loss = sum(squared(mat(cdiag_1)));
const double off_diag_loss = sum(squared(mat(off_diag)));
return diagonal_loss + lambda * off_diag_loss;
}
float get_lambda() const { return lambda; }
friend void serialize(const loss_barlow_twins_& item, std::ostream& out)
{
serialize("loss_barlow_twins_", out);
serialize(item.lambda, out);
}
friend void deserialize(loss_barlow_twins_& item, std::istream& in)
{
std::string version;
deserialize(version, in);
if (version == "loss_barlow_twins_")
{
deserialize(item.lambda, in);
}
else
{
throw serialization_error("Unexpected version found while deserializing dlib::loss_barlow_twins_. Instead found " + version);
}
}
friend std::ostream& operator<<(std::ostream& out, const loss_barlow_twins_& item)
{
out << "loss_barlow_twins (lambda=" << item.lambda << ")";
return out;
}
friend void to_xml(const loss_barlow_twins_& item, std::ostream& out)
{
out << "<loss_barlow_twins lambda='" << item.lambda << "'/>";
}
private:
float lambda = 0.0051;
mutable resizable_tensor za_norm, means_a, invstds_a;
mutable resizable_tensor zb_norm, means_b, invstds_b;
mutable resizable_tensor rms, rvs, g, b;
mutable resizable_tensor eccm, grad_input, g_grad, b_grad;
mutable resizable_tensor cdiag, cdiag_1, identity, off_mask, off_diag;
};
template <typename SUBNET>
using loss_barlow_twins = add_loss_layer<loss_barlow_twins_, SUBNET>;
}
#endif // DLIB_DNn_LOSS_H_