Add Gnuplot-based plot results for FFT MeasureExecutionTime test

src/tests/CMakeLists.txt

@@ -158,6 +158,11 @@ if(ENABLE_FPGA)
     add_definitions(-DFPGA_BLOCKS_TEST=1)
 endif(ENABLE_FPGA)
 
+find_package(Gnuplot)
+if(GNUPLOT_FOUND)
+    add_definitions(-DGNUPLOT_EXECUTABLE="${GNUPLOT_EXECUTABLE}")
+endif(GNUPLOT_FOUND)
+
 ################################################################################
 # Optional generator
 ################################################################################

src/tests/unit-tests/arithmetic/fft_length_test.cc

@@ -33,14 +33,26 @@
 #include <chrono>
 #include <functional>
 #include <random>
+#include <boost/filesystem.hpp>
 #include <gnuradio/fft/fft.h>
 
 
+#if defined GNUPLOT_EXECUTABLE
+  #include "gnuplot_i.h"
+  const bool exists_gnuplot_fft_test_length = true;
+#elif !defined GNUPLOT_EXECUTABLE
+  const bool exists_gnuplot_fft_test_length = false;
+#endif
+
+
 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");
 
 TEST(FFTLengthTest, MeasureExecutionTime)
 {
-    unsigned int fft_sizes [] = { 1000, 1024, 1960, 2000, 2048, 4000, 4096, 4725, 5000, 8000, 8192, 10368, 12000, 16000, 16384, 27000, 32768, 50000, 65536 };
+    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;
 
@@ -54,8 +66,12 @@ TEST(FFTLengthTest, MeasureExecutionTime)
     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)
@@ -73,9 +89,57 @@ TEST(FFTLengthTest, MeasureExecutionTime)
                         }
                     end = std::chrono::system_clock::now();
                     std::chrono::duration<double> elapsed_seconds = end - start;
-                    double execution_time = elapsed_seconds.count() / static_cast<double>(FLAGS_fft_iterations_test);
+                    double exec_time = elapsed_seconds.count() / static_cast<double>(FLAGS_fft_iterations_test);
-                    std::cout << "FFT execution time for length=" << d_fft_size << " : " << execution_time << " [s]" << std::endl;
+                    execution_times.push_back(exec_time * 1e3);
+                    std::cout << "FFT execution time for length=" << d_fft_size << " : " << exec_time << " [s]" << std::endl;
                     delete d_fft;
+
+                    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(FLAGS_plot_fft_length_test == true)
+        {
+            if(!exists_gnuplot_fft_test_length)
+                {
+                    std::cout << "WARNING: Although the flag plot_fft_length_test has been set to TRUE," << std::endl;
+                    std::cout << "gnuplot has not been found in your system." << std::endl;
+                    std::cout << "Test results will not be plotted." << std::endl;
+                }
+            else
+                {
+#if defined GNUPLOT_EXECUTABLE
+                    std::string gnuplot_executable = std::string(GNUPLOT_EXECUTABLE);
+                    boost::filesystem::path p(gnuplot_executable);
+                    boost::filesystem::path dir = p.parent_path();
+                    std::string gnuplot_path = dir.native();
+                    Gnuplot::set_GNUPlotPath(gnuplot_path);
+
+                    Gnuplot g1("linespoints");
+                    g1.set_title("FFT execution times for different lengths");
+                    g1.set_grid();
+                    g1.set_xlabel("FFT length");
+                    g1.set_ylabel("Execution time [ms]");
+                    g1.plot_xy(fft_sizes_v, execution_times, "FFT execution time (averaged over " + std::to_string(FLAGS_fft_iterations_test) + " iterations)");
+                    g1.set_style("points").plot_xy(powers_of_two, execution_times_powers_of_two, "Power of 2");
+                    g1.showonscreen(); // window output
+
+                    Gnuplot g2("linespoints");
+                    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);
+                    g2.plot_xy(fft_sizes_v, execution_times, "FFT execution time (averaged over " + std::to_string(FLAGS_fft_iterations_test) + " iterations)");
+                    g2.set_style("points").plot_xy(powers_of_two, execution_times_powers_of_two, "Power of 2");
+                    g2.savetops("FFT_execution_times");
+                    g2.showonscreen(); // window output
+#endif
+                }
+        }
 }