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math/test/test_gradient_descent_optimizer.cpp
Maksym Zhelyeznyakov 86a06f4131 updates
2025-10-17 19:02:59 +02:00

337 lines
9.8 KiB
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// Copyright Maksym Zhelyenzyakov 2025-2026.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// https://www.boost.org/LICENSE_1_0.txt)
#include "test_autodiff_reverse.hpp" // reuse for some basic options
#include "test_functions_for_optimization.hpp"
#include <boost/math/differentiation/autodiff_reverse.hpp>
#include <boost/math/optimization/gradient_descent.hpp>
#include <boost/math/optimization/minimizer.hpp>
namespace rdiff = boost::math::differentiation::reverse_mode;
namespace bopt = boost::math::optimization;
BOOST_AUTO_TEST_SUITE(basic_gradient_descent)
BOOST_AUTO_TEST_CASE_TEMPLATE(default_gd_test, T, all_float_types)
{
size_t NITER = 2000;
size_t N = 15;
T lr = T{ 1e-2 };
RandomSample<T> rng{ T(-100), (100) };
std::vector<rdiff::rvar<T, 1>> x_ad;
T eps = T{ 1e-3 };
for (size_t i = 0; i < N; ++i) {
x_ad.push_back(rng.next());
}
auto gdopt =
bopt::make_gradient_descent(&quadratic<rdiff::rvar<T, 1>>, x_ad, lr);
for (size_t i = 0; i < NITER; ++i) {
gdopt.step();
}
for (auto& x : x_ad) {
BOOST_REQUIRE_SMALL(x.item(), eps);
}
}
BOOST_AUTO_TEST_CASE_TEMPLATE(test_minimize, T, all_float_types)
{
size_t NITER = 2000;
size_t N = 15;
T lr = T{ 1e-2 };
RandomSample<T> rng{ T(-100), (100) };
std::vector<rdiff::rvar<T, 1>> x_ad;
T eps = T{ 1e-3 };
for (size_t i = 0; i < N; ++i) {
x_ad.push_back(rng.next());
}
auto gdopt =
bopt::make_gradient_descent(&quadratic<rdiff::rvar<T, 1>>, x_ad, lr);
auto z = minimize(gdopt);
for (auto& x : x_ad) {
BOOST_REQUIRE_SMALL(x.item(), eps);
}
}
BOOST_AUTO_TEST_CASE_TEMPLATE(random_initializer_test, T, all_float_types)
{
size_t N = 10;
T lr = T{ 1e-2 };
std::vector<rdiff::rvar<T, 1>> x(N);
auto gdopt =
bopt::make_gradient_descent(&quadratic<rdiff::rvar<T, 1>>,
x,
lr,
bopt::random_uniform_initializer_rvar<T>(
-2.0, 2.0, 1234)); // all initialized to 5
for (auto& xi : x) {
T v = xi.item();
BOOST_TEST(v >= -2);
BOOST_TEST(v <= 2);
}
gdopt.step();
}
BOOST_AUTO_TEST_CASE_TEMPLATE(const_initializer_test, T, all_float_types)
{
size_t N = 10;
T lr = T{ 1e-2 };
std::vector<rdiff::rvar<T, 1>> x(N);
auto gdopt = bopt::make_gradient_descent(
&quadratic<rdiff::rvar<T, 1>>,
x,
lr,
bopt::costant_initializer_rvar<T>(T{ 5.0 })); // all initialized to 5
for (auto& xi : x) {
T v = xi.item();
BOOST_REQUIRE_CLOSE(v, T{ 5.0 }, T{ 1e-3 });
}
gdopt.step();
}
BOOST_AUTO_TEST_CASE_TEMPLATE(box_constraint_test, T, all_float_types)
{
size_t N = 5;
T lr = T{ 1e-2 };
std::vector<rdiff::rvar<T, 1>> x(N, T{ 10 });
auto gdopt =
bopt::make_gradient_descent(&quadratic<rdiff::rvar<T, 1>>, x, lr);
auto res = bopt::minimize(
gdopt, bopt::box_constraints<std::vector<rdiff::rvar<T, 1>>, T>(-1.0, 1.0));
for (auto& xi : x) {
BOOST_TEST(xi.item() >= -1.0);
BOOST_TEST(xi.item() <= 1.0);
}
}
BOOST_AUTO_TEST_CASE_TEMPLATE(max_iter_test, T, all_float_types)
{
size_t N = 2;
T lr = T{ 1e-6 }; // very slow learning
std::vector<rdiff::rvar<T, 1>> x = { T{ 5 }, T{ 5 } };
auto gdopt =
bopt::make_gradient_descent(&quadratic<rdiff::rvar<T, 1>>, x, lr);
size_t max_iter = 50;
auto res =
bopt::minimize(gdopt,
bopt::unconstrained_policy<std::vector<rdiff::rvar<T, 1>>>{},
bopt::gradient_norm_convergence_policy<T>(T{ 1e-20 }),
bopt::max_iter_termination_policy(max_iter));
BOOST_TEST(!res.converged); // should not converge with tiny lr
BOOST_REQUIRE_EQUAL(res.num_iter, max_iter);
}
BOOST_AUTO_TEST_CASE_TEMPLATE(history_tracking_test, T, all_float_types)
{
size_t N = 3;
T lr = T{ 1e-2 };
std::vector<rdiff::rvar<T, 1>> x = { T{ 3 }, T{ -4 }, T{ 5 } };
auto gdopt =
bopt::make_gradient_descent(&quadratic<rdiff::rvar<T, 1>>, x, lr);
auto res =
bopt::minimize(gdopt,
bopt::unconstrained_policy<std::vector<rdiff::rvar<T, 1>>>{},
bopt::gradient_norm_convergence_policy<T>(T{ 1e-6 }),
bopt::max_iter_termination_policy(1000),
true); // enable history
BOOST_TEST(!res.objective_history.empty());
BOOST_TEST(res.objective_history.front() > res.objective_history.back());
}
BOOST_AUTO_TEST_CASE_TEMPLATE(rosenbrock_test, T, all_float_types)
{
std::array<rdiff::rvar<T, 1>, 2> x = { T{ -1.2 }, T{ 1.0 } }; // bad start
T lr = T{ 1e-3 };
auto gdopt =
bopt::make_gradient_descent(&rosenbrock_saddle<rdiff::rvar<T, 1>>, x, lr);
auto res = bopt::minimize(
gdopt,
bopt::unconstrained_policy<std::array<rdiff::rvar<T, 1>, 2>>{},
bopt::gradient_norm_convergence_policy<T>(T{ 1e-4 }),
bopt::max_iter_termination_policy(50000));
BOOST_TEST(res.converged);
BOOST_REQUIRE_CLOSE(x[0].item(), T{ 1.0 }, T{ 1e-1 });
BOOST_REQUIRE_CLOSE(x[1].item(), T{ 1.0 }, T{ 1e-1 });
}
BOOST_AUTO_TEST_CASE_TEMPLATE(objective_tol_convergence_test,
T,
all_float_types)
{
using policy_t = bopt::objective_tol_convergence_policy<T>;
policy_t pol(1e-3);
std::vector<T> dummy_grad;
BOOST_TEST(!pol(dummy_grad, 100.0));
BOOST_TEST(!pol(dummy_grad, 99.0));
BOOST_TEST(pol(dummy_grad, 99.0005));
}
BOOST_AUTO_TEST_CASE_TEMPLATE(relative_objective_tol_test, T, all_float_types)
{
using policy_t = bopt::relative_objective_tol_policy<T>;
policy_t pol(1e-3);
std::vector<T> dummy_grad;
BOOST_TEST(!pol(dummy_grad, 1000.0));
BOOST_TEST(!pol(dummy_grad, 1010.0));
BOOST_TEST(pol(dummy_grad, 1010.5));
}
BOOST_AUTO_TEST_CASE_TEMPLATE(combined_policy_test, T, all_float_types)
{
using pol_abs = bopt::objective_tol_convergence_policy<T>;
using pol_rel = bopt::relative_objective_tol_policy<T>;
using pol_comb = bopt::combined_convergence_policy<pol_abs, pol_rel>;
pol_abs abs_pol(1e-6);
pol_rel rel_pol(1e-3);
pol_comb comb(abs_pol, rel_pol);
std::vector<T> dummy_grad;
BOOST_TEST(!comb(dummy_grad, 100.0));
BOOST_TEST(!comb(dummy_grad, 110.0));
BOOST_TEST(comb(dummy_grad, 110.1));
BOOST_TEST(comb(dummy_grad, 110.1000001));
}
BOOST_AUTO_TEST_CASE_TEMPLATE(nonnegativity_constraint_test, T, all_float_types)
{
std::vector<T> x = { 1.0, -2.0, 3.0, -4.0 };
bopt::nonnegativity_constraint<std::vector<T>, T> proj;
proj(x);
for (auto& xi : x)
BOOST_TEST(xi >= 0.0);
BOOST_TEST(x == std::vector<T>({ 1.0, 0.0, 3.0, 0.0 }));
}
BOOST_AUTO_TEST_CASE_TEMPLATE(l2_ball_constraint_test, T, all_float_types)
{
std::vector<T> x = { 3.0, 4.0 }; // norm = 5
bopt::l2_ball_constraint<std::vector<T>, T> proj(1.0);
proj(x);
T norm = sqrt(x[0] * x[0] + x[1] * x[1]);
BOOST_TEST(abs(norm - 1.0) < 1e-12); // projected to unit circle
}
BOOST_AUTO_TEST_CASE_TEMPLATE(l1_ball_constraint_test, T, all_float_types)
{
std::vector<T> x = { 3.0, 4.0 }; // L1 norm = 7
bopt::l1_ball_constraint<std::vector<T>, T> proj(2.0);
proj(x);
T norm1 = abs(x[0]) + abs(x[1]);
BOOST_TEST(abs(norm1 - 2.0) < T{ 1e-12 });
}
BOOST_AUTO_TEST_CASE_TEMPLATE(simplex_constraint_test, T, all_float_types)
{
std::vector<T> x = { -1.0, 2.0, 3.0 }; // has negative and sum != 1
bopt::simplex_constraint<std::vector<T>, T> proj;
proj(x);
T sum = 0.0;
for (auto& xi : x) {
BOOST_TEST(xi >= 0.0); // all nonnegative
sum += xi;
}
BOOST_TEST(abs(sum - 1.0) < 1e-12); // normalized to sum=1
}
BOOST_AUTO_TEST_CASE_TEMPLATE(unit_sphere_constraint_test, T, all_float_types)
{
std::vector<T> x = { 0.3, 0.4 }; // norm = 0.5
bopt::unit_sphere_constraint<std::vector<T>, T> proj;
proj(x);
T norm = sqrt(x[0] * x[0] + x[1] * x[1]);
BOOST_TEST(abs(norm - 1.0) < 1e-12); // always projected to sphere
}
BOOST_AUTO_TEST_CASE_TEMPLATE(function_constraint_test, T, all_float_types)
{
auto clip_to_half = [](std::vector<T>& v) {
for (auto& xi : v)
if (xi > 0.5)
xi = 0.5;
};
bopt::function_constraint<std::vector<T>> proj(clip_to_half);
std::vector<T> x = { 0.2, 0.7, 1.5 };
proj(x);
BOOST_TEST(x == std::vector<T>({ 0.2, 0.5, 0.5 }));
}
template<typename RealType>
struct no_init_policy
{
void operator()(std::vector<RealType>& x) const noexcept {}
};
template<typename RealType>
struct analytic_objective_eval_pol
{
template<typename Objective, typename ArgumentContainer>
RealType operator()(Objective&& objective, ArgumentContainer& x)
{
return objective(x);
}
};
template<typename RealType>
struct analytic_gradient_eval_pol
{
template<class Objective,
class ArgumentContainer,
class FunctionEvaluationPolicy>
void operator()(Objective&& obj_f,
ArgumentContainer& x,
FunctionEvaluationPolicy&& f_eval_pol,
RealType& obj_v,
std::vector<RealType>& grad_container)
{
RealType v = f_eval_pol(obj_f, x);
obj_v = v;
grad_container.resize(x.size());
for (size_t i = 0; i < x.size(); ++i) {
grad_container[i] = 2 * x[i];
}
}
};
BOOST_AUTO_TEST_CASE_TEMPLATE(analytic_derivative_policies, T, all_float_types)
{
std::vector<T> x;
size_t NITER = 2000;
size_t N = 15;
T lr = T{ 1e-2 };
RandomSample<T> rng{ T(-100), (100) };
T eps = T{ 1e-3 };
for (size_t i = 0; i < N; ++i) {
x.push_back(rng.next());
}
auto gdopt = bopt::make_gradient_descent(&quadratic<T>,
x,
lr,
no_init_policy<T>{},
analytic_objective_eval_pol<T>{},
analytic_gradient_eval_pol<T>{});
for (size_t i = 0; i < NITER; ++i) {
gdopt.step();
}
for (auto& xi : x) {
BOOST_REQUIRE_SMALL(xi, eps);
}
}
BOOST_AUTO_TEST_SUITE_END()