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gnss-sdr/tests/unit-tests/arithmetic/fft_length_test.cc

187 lines
8.3 KiB
C++

/*!
* \file fft_length_test.cc
* \brief This file implements timing tests for the FFT.
* \author Carles Fernandez-Prades, 2016. cfernandez(at)cttc.es
*
*
* -----------------------------------------------------------------------------
*
* GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
* This file is part of GNSS-SDR.
*
* Copyright (C) 2010-2020 (see AUTHORS file for a list of contributors)
* SPDX-License-Identifier: GPL-3.0-or-later
*
* -----------------------------------------------------------------------------
*/
#include "gnss_sdr_fft.h"
#include "gnss_sdr_filesystem.h"
#include "gnuplot_i.h"
#include "test_flags.h"
#include <algorithm>
#include <chrono>
#include <functional>
#include <random>
#if USE_GLOG_AND_GFLAGS
DEFINE_int32(fft_iterations_test, 1000, "Number of averaged iterations in FFT length timing test");
DEFINE_bool(plot_fft_length_test, false, "Plots results of FFTLengthTest with gnuplot");
#else
ABSL_FLAG(int32_t, fft_iterations_test, 1000, "Number of averaged iterations in FFT length timing test");
ABSL_FLAG(bool, plot_fft_length_test, false, "Plots results of FFTLengthTest with gnuplot");
#endif
// Note from FFTW documentation: the standard FFTW distribution works most efficiently for arrays whose
// size can be factored into small primes (2, 3, 5, and 7), and otherwise it uses a slower general-purpose routine.
TEST(FFTLengthTest, MeasureExecutionTime)
{
unsigned int fft_sizes[] = {512, 1000, 1024, 1100, 1297, 1400, 1500, 1960, 2000, 2048, 2221, 2500, 3000, 3500, 4000,
4096, 4200, 4500, 4725, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8192, 8500, 9000, 9500, 10000, 10368, 11000,
12000, 15000, 16000, 16384, 27000, 32768, 50000, 65536};
std::chrono::time_point<std::chrono::system_clock> start, end;
std::random_device r;
std::default_random_engine e1(r());
std::default_random_engine e2(r());
std::uniform_real_distribution<float> uniform_dist(-1, 1);
auto func = [](float a, float b) { return gr_complex(a, b); }; // Helper lambda function that returns a gr_complex
auto random_number1 = std::bind(uniform_dist, e1);
auto random_number2 = std::bind(uniform_dist, e2);
auto gen = std::bind(func, random_number1, random_number2); // Function that returns a random gr_complex
std::vector<unsigned int> fft_sizes_v(fft_sizes, fft_sizes + sizeof(fft_sizes) / sizeof(unsigned int));
std::sort(fft_sizes_v.begin(), fft_sizes_v.end());
std::vector<unsigned int>::const_iterator it;
unsigned int d_fft_size;
std::vector<double> execution_times;
std::vector<unsigned int> powers_of_two;
std::vector<double> execution_times_powers_of_two;
EXPECT_NO_THROW(
for (it = fft_sizes_v.cbegin(); it != fft_sizes_v.cend(); ++it) {
d_fft_size = *it;
auto d_fft = gnss_fft_fwd_make_unique(d_fft_size);
std::generate_n(d_fft->get_inbuf(), d_fft_size, gen);
start = std::chrono::system_clock::now();
#if USE_GLOG_AND_GFLAGS
for (int k = 0; k < FLAGS_fft_iterations_test; k++)
#else
for (int k = 0; k < absl::GetFlag(FLAGS_fft_iterations_test); k++)
#endif
{
d_fft->execute();
}
end = std::chrono::system_clock::now();
std::chrono::duration<double> elapsed_seconds = end - start;
#if USE_GLOG_AND_GFLAGS
double exec_time = elapsed_seconds.count() / static_cast<double>(FLAGS_fft_iterations_test);
#else
double exec_time = elapsed_seconds.count() / static_cast<double>(absl::GetFlag(FLAGS_fft_iterations_test));
#endif
execution_times.push_back(exec_time * 1e3);
std::cout << "FFT execution time for length=" << d_fft_size << " : " << exec_time << " [s]\n";
if ((d_fft_size & (d_fft_size - 1)) == 0) // if it is a power of two
{
powers_of_two.push_back(d_fft_size);
execution_times_powers_of_two.push_back(exec_time / 1e-3);
}
});
#if USE_GLOG_AND_GFLAGS
if (FLAGS_plot_fft_length_test == true)
{
const std::string gnuplot_executable(FLAGS_gnuplot_executable);
#else
if (absl::GetFlag(FLAGS_plot_fft_length_test) == true)
{
const std::string gnuplot_executable(absl::GetFlag(FLAGS_gnuplot_executable));
#endif
if (gnuplot_executable.empty())
{
std::cout << "WARNING: Although the flag plot_fft_length_test has been set to TRUE,\n";
std::cout << "gnuplot has not been found in your system.\n";
std::cout << "Test results will not be plotted.\n";
}
else
{
try
{
fs::path p(gnuplot_executable);
fs::path dir = p.parent_path();
const std::string& gnuplot_path = dir.native();
Gnuplot::set_GNUPlotPath(gnuplot_path);
Gnuplot g1("linespoints");
#if USE_GLOG_AND_GFLAGS
if (FLAGS_show_plots)
#else
if (absl::GetFlag(FLAGS_show_plots))
#endif
{
g1.showonscreen(); // window output
}
else
{
g1.disablescreen();
}
g1.set_title("FFT execution times for different lengths");
g1.set_grid();
g1.set_xlabel("FFT length");
g1.set_ylabel("Execution time [ms]");
#if USE_GLOG_AND_GFLAGS
g1.plot_xy(fft_sizes_v, execution_times, "FFT execution time (averaged over " + std::to_string(FLAGS_fft_iterations_test) + " iterations)");
#else
g1.plot_xy(fft_sizes_v, execution_times, "FFT execution time (averaged over " + std::to_string(absl::GetFlag(FLAGS_fft_iterations_test)) + " iterations)");
#endif
g1.set_style("points").plot_xy(powers_of_two, execution_times_powers_of_two, "Power of 2");
g1.savetops("FFT_execution_times_extended");
g1.savetopdf("FFT_execution_times_extended", 18);
Gnuplot g2("linespoints");
#if USE_GLOG_AND_GFLAGS
if (FLAGS_show_plots)
#else
if (absl::GetFlag(FLAGS_show_plots))
#endif
{
g2.showonscreen(); // window output
}
else
{
g2.disablescreen();
}
g2.set_title("FFT execution times for different lengths (up to 2^{14}=16384)");
g2.set_grid();
g2.set_xlabel("FFT length");
g2.set_ylabel("Execution time [ms]");
g2.set_xrange(0, 16384);
#if USE_GLOG_AND_GFLAGS
g2.plot_xy(fft_sizes_v, execution_times, "FFT execution time (averaged over " + std::to_string(FLAGS_fft_iterations_test) + " iterations)");
#else
g2.plot_xy(fft_sizes_v, execution_times, "FFT execution time (averaged over " + std::to_string(absl::GetFlag(FLAGS_fft_iterations_test)) + " iterations)");
#endif
g2.set_style("points").plot_xy(powers_of_two, execution_times_powers_of_two, "Power of 2");
g2.savetops("FFT_execution_times");
g2.savetopdf("FFT_execution_times", 18);
#if USE_GLOG_AND_GFLAGS
if (FLAGS_show_plots)
#else
if (absl::GetFlag(FLAGS_show_plots))
#endif
{
g2.showonscreen(); // window output
}
}
catch (const GnuplotException& ge)
{
std::cout << ge.what() << '\n';
}
}
}
}