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ensmallen/tests/parallel_sgd_test.cpp
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/**
* @file parallel_sgd_test.cpp
* @author Shikhar Bhardwaj
* @author Marcus Edel
* @author Conrad Sanderson
*
* ensmallen is free software; you may redistribute it and/or modify it under
* the terms of the 3-clause BSD license. You should have received a copy of
* the 3-clause BSD license along with ensmallen. If not, see
* http://www.opensource.org/licenses/BSD-3-Clause for more information.
*/
#include <ensmallen.hpp>
#include "catch.hpp"
#include "test_function_tools.hpp"
using namespace std;
using namespace arma;
using namespace ens;
using namespace ens::test;
// These tests are only compiled if OpenMP is used.
#ifdef ENS_USE_OPENMP
/**
* Test the correctness of the Parallel SGD implementation using a specified
* sparse test function, with guaranteed disjoint updates between different
* threads.
*/
TEST_CASE("SimpleParallelSGDTest", "[ParallelSGDTest]")
{
ConstantStep decayPolicy(0.4);
// The batch size for this test should be chosen according to the threads
// available on the system. If the update does not touch each datapoint, the
// test will fail.
size_t threadsAvailable = omp_get_max_threads();
SparseTestFunction f;
for (size_t i = threadsAvailable; i > 0; --i)
{
omp_set_num_threads(i);
size_t batchSize = std::ceil((float) f.NumFunctions() / i);
ParallelSGD<ConstantStep> s(10000, batchSize, 1e-5, true, decayPolicy);
FunctionTest<SparseTestFunction>(s, 0.01, 0.001);
}
}
/**
* When run with a single thread, parallel SGD should be identical to normal
* SGD.
*/
TEST_CASE("ParallelSGDGeneralizedRosenbrockTest", "[ParallelSGDTest]")
{
// Loop over several variants.
for (size_t i = 10; i < 30; i += 5)
{
// Create the generalized Rosenbrock function.
GeneralizedRosenbrockFunction f(i);
ConstantStep decayPolicy(0.001);
ParallelSGD<ConstantStep> s(100000, f.NumFunctions(), 1e-12, true, decayPolicy);
arma::mat coordinates = f.GetInitialPoint();
omp_set_num_threads(1);
double result = s.Optimize(f, coordinates);
REQUIRE(result == Approx(0.0).margin(1e-8));
for (size_t j = 0; j < i; ++j)
REQUIRE(coordinates(j) == Approx(1.0).epsilon(0.0001));
}
}
/**
* Check that parallel SGD works with arma::fmat.
*/
TEST_CASE("ParallelSGDGeneralizedRosenbrockFMatTest", "[ParallelSGDTest]")
{
// Loop over several variants.
for (size_t i = 10; i < 30; i += 5)
{
// Create the generalized Rosenbrock function.
GeneralizedRosenbrockFunction f(i);
ConstantStep decayPolicy(0.001);
ParallelSGD<ConstantStep> s(100000, f.NumFunctions(), 1e-12, true, decayPolicy);
arma::fmat coordinates = f.GetInitialPoint<arma::fmat>();
omp_set_num_threads(1);
float result = s.Optimize(f, coordinates);
REQUIRE(result == Approx(0.0).margin(1e-8));
for (size_t j = 0; j < i; ++j)
REQUIRE(coordinates(j) == Approx(1.0).epsilon(0.001));
}
}
/**
* Check that parallel SGD works with arma::sp_mat.
*/
TEST_CASE("ParallelSGDGeneralizedRosenbrockSpMatTest", "[ParallelSGDTest]")
{
// Loop over several variants.
for (size_t i = 10; i < 30; i += 5)
{
// Create the generalized Rosenbrock function.
GeneralizedRosenbrockFunction f(i);
ConstantStep decayPolicy(0.001);
ParallelSGD<ConstantStep> s(100000, f.NumFunctions(), 1e-12, true, decayPolicy);
arma::sp_mat coordinates = f.GetInitialPoint<arma::sp_mat>();
omp_set_num_threads(1);
double result = s.Optimize(f, coordinates);
REQUIRE(result == Approx(0.0).margin(1e-8));
for (size_t j = 0; j < i; ++j)
REQUIRE(coordinates(j) == Approx(1.0).epsilon(0.0001));
}
}
#endif
/**
* Test the correctness of the Exponential backoff stepsize decay policy.
*/
TEST_CASE("ExponentialBackoffDecayTest", "[ParallelSGDTest]")
{
ExponentialBackoff decayPolicy(100, 100, 0.9);
// At the first iteration, stepsize should be unchanged
REQUIRE(decayPolicy.StepSize(1) == 100);
// At the 99th iteration, stepsize should be unchanged
REQUIRE(decayPolicy.StepSize(99) == 100);
// At the 100th iteration, stepsize should be changed
REQUIRE(decayPolicy.StepSize(100) == 90);
// At the 210th iteration, stepsize should be unchanged
REQUIRE(decayPolicy.StepSize(210) == 90);
// At the 211th iteration, stepsize should be changed
REQUIRE(decayPolicy.StepSize(211) == 81);
}