#pragma once
/*
* Copyright (C) 2024 Brett Terpstra
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
#ifndef COSC_4P80_ASSIGNMENT_2_LAYER_H
#define COSC_4P80_ASSIGNMENT_2_LAYER_H
#include
#include
#include "blt/iterator/zip.h"
#include "blt/iterator/iterator.h"
namespace assign2
{
class neuron_t
{
friend layer_t;
public:
// empty neuron for loading from a stream
explicit neuron_t(weight_view weights): weights(weights)
{}
// neuron with bias
explicit neuron_t(weight_view weights, Scalar bias): bias(bias), weights(weights)
{}
Scalar activate(const Scalar* inputs, function_t* act_func)
{
z = bias;
for (auto [x, w] : blt::zip_iterator_container({inputs, inputs + weights.size()}, {weights.begin(), weights.end()}))
z += x * w;
a = act_func->call(z);
return a;
}
template
OStream& serialize(OStream& stream)
{
stream << bias;
for (auto d : weights)
stream << d;
}
template
IStream& deserialize(IStream& stream)
{
for (auto& d : blt::iterate(weights).rev())
stream >> d;
stream >> bias;
}
void debug() const
{
std::cout << bias << " ";
}
private:
float z = 0;
float a = 0;
float bias = 0;
float error = 0;
weight_view weights;
};
class layer_t
{
public:
template
layer_t(const blt::i32 in, const blt::i32 out, function_t* act_func, WeightFunc w, BiasFunc b):
in_size(in), out_size(out), act_func(act_func)
{
neurons.reserve(out_size);
for (blt::i32 i = 0; i < out_size; i++)
{
auto weight = weights.allocate_view(in_size);
for (auto& v : weight)
v = w(i);
neurons.push_back(neuron_t{weight, b(i)});
}
}
std::vector call(const std::vector& in)
{
std::vector out;
out.reserve(out_size);
#if BLT_DEBUG_LEVEL > 0
if (in.size() != in_size)
throw std::runtime_exception("Input vector doesn't match expected input size!");
#endif
for (auto& n : neurons)
out.push_back(n.activate(in.data(), act_func));
return out;
}
Scalar back_prop(const std::vector& prev_layer_output, Scalar error, const layer_t& next_layer, bool is_output)
{
std::vector dw;
// δ(h)
if (is_output)
{
// assign error to output layer
for (auto& n : neurons)
n.error = act_func->derivative(n.z) * error; // f'act(net(h)) * (error)
} else
{
// first calculate and assign input layer error
std::vector next_error;
next_error.resize(next_layer.neurons.size());
for (const auto& [i, w] : blt::enumerate(next_layer.neurons))
{
for (auto wv : w.weights)
next_error[i] += w.error * wv;
// needed?
next_error[i] /= static_cast(w.weights.size());
}
for (auto& n : neurons)
{
n.error = act_func->derivative(n.z);
}
}
for (const auto& v : prev_layer_output)
{
}
return error_at_current_layer;
}
template
OStream& serialize(OStream& stream)
{
for (auto d : neurons)
stream << d;
}
template
IStream& deserialize(IStream& stream)
{
for (auto& d : blt::iterate(neurons).rev())
stream >> d;
}
[[nodiscard]] inline blt::i32 get_in_size() const
{
return in_size;
}
[[nodiscard]] inline blt::i32 get_out_size() const
{
return out_size;
}
void debug() const
{
std::cout << "Bias: ";
for (auto& v : neurons)
v.debug();
std::cout << std::endl;
weights.debug();
}
private:
const blt::i32 in_size, out_size;
weight_t weights;
function_t* act_func;
std::vector neurons;
};
}
#endif //COSC_4P80_ASSIGNMENT_2_LAYER_H