psemek/libs/ml/tests/neural_net/gradient.cpp

107 lines
3.1 KiB
C++

#include <psemek/test/test.hpp>
#include <psemek/ml/neural_net/learner.hpp>
#include <psemek/ml/neural_net/evaluator.hpp>
#include <psemek/ml/neural_net/randomize.hpp>
#include <psemek/ml/neural_net/loss.hpp>
#include <psemek/random/generator.hpp>
#include <psemek/random/uniform.hpp>
#include <psemek/math/math.hpp>
using namespace psemek::ml;
using namespace psemek::random;
using namespace psemek::math;
test_case(ml_neural__net_gradient)
{
generator rng;
for (std::size_t iteration = 0; iteration < 64; ++iteration)
{
std::vector<std::size_t> sizes;
sizes.resize(uniform<std::size_t>(rng, 2, 5));
for (auto & s : sizes)
s = uniform<std::size_t>(rng, 1, 50);
std::vector<activation_type> activations(sizes.size() - 1);
for (auto & a : activations)
a = static_cast<activation_type>(uniform<std::size_t>(rng, 0, static_cast<std::size_t>(activation_type_values().size()) - 1));
neural_net<double> nn(std::move(sizes), std::move(activations));
randomize_normal(nn, rng);
std::vector<double> input(nn.layer_sizes().front());
for (auto & x : input)
x = uniform<double>(rng);
std::vector<double> output(nn.layer_sizes().back());
for (auto & x : output)
x = uniform<double>(rng);
neural_net_learner<double> learner;
learner.apply(nn, input);
learner.backpropagate_l2(nn, output);
double const eps = 1e-6;
neural_net_evaluator<double> evaluator;
for (std::size_t i = 0; i < nn.weights().size(); ++i)
{
double old = nn.weights()[i];
nn.weights()[i] -= eps;
double v0 = l2_loss(evaluator.apply(nn, input), output);
nn.weights()[i] += 2.0 * eps;
double v1 = l2_loss(evaluator.apply(nn, input), output);
nn.weights()[i] = old;
double numeric_gradient = (v1 - v0) / 2.0 / eps;
expect_close(numeric_gradient, learner.gradient()[i], 1e-4);
}
}
}
test_case(ml_neural__net_arg__gradient)
{
generator rng;
for (std::size_t iteration = 0; iteration < 64; ++iteration)
{
std::vector<std::size_t> sizes;
sizes.resize(uniform<std::size_t>(rng, 2, 5));
for (auto & s : sizes)
s = uniform<std::size_t>(rng, 1, 50);
std::vector<activation_type> activations(sizes.size() - 1);
for (auto & a : activations)
a = static_cast<activation_type>(uniform<std::size_t>(rng, 0, static_cast<std::size_t>(activation_type_values().size()) - 1));
neural_net<double> nn(std::move(sizes), std::move(activations));
randomize_normal(nn, rng);
std::vector<double> input(nn.layer_sizes().front());
for (auto & x : input)
x = uniform<double>(rng);
std::vector<double> output(nn.layer_sizes().back());
for (auto & x : output)
x = uniform<double>(rng);
neural_net_learner<double> learner;
learner.apply(nn, input);
learner.backpropagate_l2(nn, output);
double const eps = 1e-6;
neural_net_evaluator<double> evaluator;
for (std::size_t i = 0; i < input.size(); ++i)
{
double old = input[i];
input[i] -= eps;
double v0 = l2_loss(evaluator.apply(nn, input), output);
input[i] += 2.0 * eps;
double v1 = l2_loss(evaluator.apply(nn, input), output);
input[i] = old;
double numeric_gradient = (v1 - v0) / 2.0 / eps;
expect_close(numeric_gradient, learner.arg_gradient()[i], 1e-4);
}
}
}