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Flux/include/modules/neural_networks/optimizers/Optimizer_SGD.h
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Optimizers - Part 1
Done with SGD and Adagrad, still need to optimize them but they work.
2026-01-01 19:23:48 +01:00

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3.3 KiB
C++

#pragma once
#include "./core/omp_config.h"
#include "./utils/vector.h"
#include "./utils/matrix.h"
#include "./numerics/matmul.h"
namespace neural_networks{
template <typename T>
struct Optimizer_SGD{
T learning_rate = T{1};
T current_learning_rate = learning_rate;
T decay = T{0};
T momentum = T{0};
uint64_t iterations = 0;
utils::Matrix<T> weight_updates;
utils::Vector<T> bias_updates;
// Default Constructor
Optimizer_SGD() = default;
// Constructor
explicit Optimizer_SGD(const T lr, const T lr_decay, const T momentums): learning_rate(lr), current_learning_rate{lr}, decay(lr_decay), momentum(momentums) {}
void pre_update_params(){
if(decay){
current_learning_rate = learning_rate * (T{1}/(T{1}+(decay*iterations)));
//std::cout << current_learning_rate << std::endl;
}
}
template <typename Layer>
void update_params(Layer& layer){
// if we use momentum
if(momentum){
// if layer does not contain momentum arrays, create them filled with zeros.
if ((layer.weight_momentums.rows() != layer.weights.rows()) || (layer.weight_momentums.cols() != layer.weights.cols())){
layer.weight_momentums.resize(layer.weights.rows(), layer.weights.cols(), T{0});
}
if (layer.bias_momentums.size() != layer.biases.size()){
layer.bias_momentums.resize(layer.biases.size(), T{0});
}
// Build weight updates with momentum - take previous updates,
// multiplied by retain factor and update with current gradients
weight_updates.resize(layer.weights.rows(),layer.weights.cols()); // can be optimized out later
for (uint64_t i = 0; i < layer.weights.rows(); ++i){
for (uint64_t j = 0; j < layer.weights.cols(); ++j){
weight_updates(i,j) = (momentum*layer.weight_momentums(i,j)) - (current_learning_rate*layer.dweights(i,j));
}
}
layer.weight_momentums = weight_updates;
// Build bias update
bias_updates.resize(layer.biases.size()); // can be optimized out later
for (uint64_t i = 0; i < layer.biases.size(); ++i){
bias_updates[i] = (momentum*layer.bias_momentums[i]) - (current_learning_rate*layer.dbiases[i]);
}
layer.bias_momentums = bias_updates;
}else{
weight_updates.resize(layer.weights.rows(),layer.weights.cols()); // can be optimized out later
// weights -= lr * dweights
for (uint64_t i = 0; i < layer.weights.rows(); ++i){
for (uint64_t j = 0; j < layer.weights.cols(); ++j){
weight_updates(i,j) -= current_learning_rate*layer.dweights(i,j);
}
}
bias_updates.resize(layer.biases.size()); // can be optimized out later
// biases -= lr * dbiases
for (uint64_t i = 0; i < layer.biases.size(); ++i){
bias_updates[i] -= current_learning_rate * layer.dbiases[i];
}
}
for (uint64_t i = 0; i < layer.weights.rows(); ++i){
for (uint64_t j = 0; j < layer.weights.cols(); ++j){
layer.weights(i,j) += weight_updates(i,j);
}
}
}
void post_update_params(){
iterations++;
}
};
} // end namespace neural_networks