Added Armadillo VS GNU Radio FFT speed test

Unit test comparing the two FFT implementations

src/tests/test_main.cc

@@ -69,6 +69,7 @@ DECLARE_string(log_dir);
 #include "unit-tests/arithmetic/multiply_test.cc"
 #include "unit-tests/arithmetic/code_generation_test.cc"
 #include "unit-tests/arithmetic/fft_length_test.cc"
+#include "unit-tests/arithmetic/fft_speed_test.cc"
 
 #include "unit-tests/control-plane/file_configuration_test.cc"
 #include "unit-tests/control-plane/in_memory_configuration_test.cc"

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

@@ -0,0 +1,84 @@
+/*!
+ * \file fft_speed_test.cc
+ * \brief  This file implements timing tests for the Armadillo
+ *         and GNU Radio FFT implementations
+ * \author Antonio Ramos, 2017. antonio.ramos(at)cttc.es
+ *
+ *
+ * -------------------------------------------------------------------------
+ *
+ * Copyright (C) 2010-2017  (see AUTHORS file for a list of contributors)
+ *
+ * GNSS-SDR is a software defined Global Navigation
+ *          Satellite Systems receiver
+ *
+ * This file is part of GNSS-SDR.
+ *
+ * GNSS-SDR is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GNSS-SDR is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNSS-SDR. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * -------------------------------------------------------------------------
+ */
+
+#include <chrono>
+#include <memory>
+#include <gnuradio/fft/fft.h>
+#include <armadillo>
+
+
+DEFINE_int32(fft_speed_iterations_test, 1000, "Number of averaged iterations in FFT length timing test");
+
+TEST(FFTSpeedTest, ArmadilloVSGNURadioExecutionTime)
+{
+    unsigned int d_fft_size;
+    std::chrono::time_point<std::chrono::system_clock> start, end;
+    std::chrono::duration<double> elapsed_seconds;
+
+    unsigned int fft_sizes [13] = { 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536 };
+    double d_execution_time;
+    EXPECT_NO_THROW(
+            for(int i = 0; i < 13; i++)
+                {
+                    d_fft_size = fft_sizes[i];    
+                    
+                    gr::fft::fft_complex* d_gr_fft;
+                    d_gr_fft = new gr::fft::fft_complex(d_fft_size, true);
+                    
+                    arma::cx_vec d_arma_fft(d_fft_size);
+                    d_arma_fft = arma::cx_vec(d_fft_size).randn() + gr_complex(0.0, 1.0) * arma::cx_vec(d_fft_size).randn();
+                    
+                    memcpy(d_gr_fft->get_inbuf(), d_arma_fft.memptr(), sizeof(gr_complex) * d_fft_size);
+                    
+                    start = std::chrono::system_clock::now();
+                    for(int k = 0; k < FLAGS_fft_speed_iterations_test; k++)
+                        {
+                            d_gr_fft->execute();
+                        }
+                    end = std::chrono::system_clock::now();
+                    elapsed_seconds = end - start;
+                    d_execution_time = elapsed_seconds.count() / static_cast<double>(FLAGS_fft_speed_iterations_test);
+                    std::cout << "GNU Radio FFT execution time for length = " << d_fft_size << " : " << d_execution_time << " [s]" << std::endl;
+                    delete d_gr_fft;
+                    
+                    start = std::chrono::system_clock::now();
+                    for(int k = 0; k < FLAGS_fft_speed_iterations_test; k++)
+                        {
+                            arma::fft(d_arma_fft);
+                        }
+                    end = std::chrono::system_clock::now();
+                    elapsed_seconds = end - start;
+                    d_execution_time = elapsed_seconds.count() / static_cast<double>(FLAGS_fft_speed_iterations_test);
+                    std::cout << "Armadillo FFT execution time for length = " << d_fft_size << " : " << d_execution_time << " [s]" << std::endl;
+                }
+    );
+}