Removed unused code from create_zc (MATLAB)

There were issues before where the single MATLAB instance would cause a segfault at the end of the test
Now it truly uses a single instance

gnuradio/gr-dji_droneid/include/gnuradio/dji_droneid/utils.h

@@ -24,18 +24,61 @@ namespace dji_droneid {
 class DJI_DRONEID_API utils
 {
 public:
-    utils();
-    ~utils();
+    utils() = default;
+    ~utils() = default;
 
+    // Hz between each carrier in DroneID
     static constexpr float CARRIER_SPACING = 15e3;
-    static constexpr uint32_t DATA_CARRIER_COUNT = 600;
-    static constexpr std::complex<float> I = std::complex<float>(0, 1);
 
+    // Number of OFDM data carriers in DroneID (independent of sample rate)
+    static constexpr uint32_t DATA_CARRIER_COUNT = 600;
+
+    /**
+     * Get the correct FFT size based on the sample rate
+     * @param sample_rate Sample rate (in Hz) of the collected samples
+     * @return Number of FFT bins required
+     */
     static uint32_t get_fft_size(float sample_rate);
+
+    /**
+     * Get the correct sample rate based on the FFT size
+     * @param fft_size Number of FFT bins
+     * @return Sample rate (in Hz)
+     */
     static float get_sample_rate(uint32_t fft_size);
+
+    /**
+     * Get a list of FFT bins (all positive, assuming that DC is in the middle) that should be used as data carriers
+     * @param sample_rate Sample rate (in Hz)
+     * @return List of utils::DATA_CARRIER_COUNT values denoting position of all data carriers
+     */
     static std::vector<uint32_t> get_data_carrier_indices(float sample_rate);
+
+    /**
+     * Create a Zadoff Chu sequence of `length` elements using the root index `root`
+     * @param root Root index
+     * @param length Number of elements to create
+     * @return Vector of complex floats
+     */
     static std::vector<std::complex<float>> zadoff_chu(uint32_t root, uint32_t length);
+
+    /**
+     * Create a time domain ZC sequence for the specified OFDM symbol index (4 or 6)
+     *
+     * Will be `fft_size` elements long
+     *
+     * <b>This only currently works for drones that have two ZC sequences present!!!</b>
+     * @param fft_size Number of FFT bins the sequence should be generated for
+     * @param symbol_idx Symbol index to generate the sequence for (must be 4 or 6)
+     * @return Complex float vector of `fft_bins` elements representing the gold ZC sequence in the time domain
+     */
     static std::vector<std::complex<float>> create_zc(uint32_t fft_size, uint8_t symbol_idx);
+
+    /**
+     * Get the long and short cyclic prefix lengths for the provided sample rate
+     * @param sample_rate Sample rate (in Hz)
+     * @return Pair with the first element being the long cyclic prefix length in samples, second being the short
+     */
     static std::pair<uint16_t, uint16_t> get_cyclic_prefix_lengths(float sample_rate);
 
 private:
@@ -44,6 +87,4 @@ private:
 } // namespace dji_droneid
 } // namespace gr
 
-
-
 #endif /* INCLUDED_DJI_DRONEID_UTILS_H */

gnuradio/gr-dji_droneid/lib/qa_utils.cc

@@ -19,27 +19,32 @@ using namespace matlab::engine;
 std::unique_ptr<MATLABEngine> matlab_engine = nullptr;
 matlab::data::ArrayFactory factory;
 
+struct MatlabHandler {
+    MatlabHandler() {
+        matlab_engine = startMATLAB();
+        matlab_engine->eval(u"addpath(genpath('" MATLAB_SOURCE_PATH "'));");
+    }
+
+    ~MatlabHandler() {
+        matlab_engine = nullptr;
+    }
+};
+
+BOOST_GLOBAL_FIXTURE(MatlabHandler);
+
 struct TestFixture {
     TestFixture () {
-        if (matlab_engine == nullptr) {
-            BOOST_TEST_MESSAGE("Starting MATLAB");
-            matlab_engine = startMATLAB();
-            BOOST_TEST_MESSAGE("MATLAB started");
-            matlab_engine->eval(u"addpath(genpath('" MATLAB_SOURCE_PATH "'));");
-            BOOST_TEST_MESSAGE("Added MATLAB source directory " MATLAB_SOURCE_PATH " to the path");
-        } else {
-            BOOST_TEST_MESSAGE("MATLAB already running");
-        }
+        BOOST_REQUIRE(matlab_engine != nullptr);
     }
 
     static void setup() {
+        // Since the MATLAB instance is never reset, the workspace needs to be cleared each time for sanity
         TestFixture::clear_workspace();
     }
 
     ~TestFixture() = default;
 
     static void clear_workspace() {
-        std::cout << "[INFO] Clearing workspace\n";
         matlab_engine->eval(u"clear all;");
     }
 
@@ -65,8 +70,6 @@ struct TestFixture {
         matlab_engine->setVariable("fft_size", factory.createScalar(static_cast<double>(fft_size)));
         matlab_engine->setVariable("symbol_idx", factory.createScalar(static_cast<double>(symbol_idx)));
         matlab_engine->eval(u"zc = create_zc(fft_size, symbol_idx);");
-        matlab_engine->eval(u"fft_size");
-        matlab_engine->eval(u"symbol_idx");
 
         const matlab::data::TypedArray<std::complex<double>> ret = matlab_engine->getVariable("zc");
 
@@ -112,8 +115,9 @@ struct TestFixture {
     }
 };
 
+BOOST_FIXTURE_TEST_SUITE(Utils_Test_Suite, TestFixture);
 
-BOOST_FIXTURE_TEST_CASE(test_utils__get_fft_size, TestFixture)
+BOOST_AUTO_TEST_CASE(test_utils__get_fft_size)
 {
     const std::vector<float> rates = {15.36e6, 30.72e6, 61.44e6};
     for (const auto & rate : rates) {
@@ -126,7 +130,7 @@ BOOST_FIXTURE_TEST_CASE(test_utils__get_fft_size, TestFixture)
     BOOST_REQUIRE_THROW(utils::get_fft_size(10.1e6), std::runtime_error);
 }
 
-BOOST_FIXTURE_TEST_CASE(test_utils__get_data_carrier_indices, TestFixture)
+BOOST_AUTO_TEST_CASE(test_utils__get_data_carrier_indices)
 {
     const std::vector<float> rates = {15.36e6, 30.72e6, 61.44e6};
     for (const auto & rate : rates) {
@@ -137,7 +141,7 @@ BOOST_FIXTURE_TEST_CASE(test_utils__get_data_carrier_indices, TestFixture)
     }
 }
 
-BOOST_FIXTURE_TEST_CASE(test_utils__get_sample_rate, TestFixture) {
+BOOST_AUTO_TEST_CASE(test_utils__get_sample_rate) {
     const std::vector<uint32_t> fft_sizes = {1024, 2048, 4096, 8192, 16384};
     for (const auto & fft_size : fft_sizes) {
         const auto expected = static_cast<float>(fft_size) * utils::CARRIER_SPACING;
@@ -147,7 +151,7 @@ BOOST_FIXTURE_TEST_CASE(test_utils__get_sample_rate, TestFixture) {
     }
 }
 
-BOOST_FIXTURE_TEST_CASE(test_utils__create_zc, TestFixture) {
+BOOST_AUTO_TEST_CASE(test_utils__create_zc) {
     const std::vector<uint32_t> lengths = {1024, 2048, 4096, 8192};
     const std::vector<uint8_t> symbol_indices = {4, 6};
 
@@ -170,7 +174,7 @@ BOOST_FIXTURE_TEST_CASE(test_utils__create_zc, TestFixture) {
     }
 }
 
-BOOST_FIXTURE_TEST_CASE(test_utils__zadoff_chu, TestFixture) {
+BOOST_AUTO_TEST_CASE(test_utils__zadoff_chu) {
     std::vector<uint32_t> roots = {600, 147};
     std::vector<uint32_t> lengths = {601};
 
@@ -185,7 +189,7 @@ BOOST_FIXTURE_TEST_CASE(test_utils__zadoff_chu, TestFixture) {
     }
 }
 
-BOOST_FIXTURE_TEST_CASE(test_utils__get_cyclic_prefix, TestFixture) {
+BOOST_AUTO_TEST_CASE(test_utils__get_cyclic_prefix) {
     std::vector<float> sample_rates = {15.36e6, 30.72e6, 61.44e6};
 
     for (const auto & sample_rate : sample_rates) {
@@ -197,5 +201,7 @@ BOOST_FIXTURE_TEST_CASE(test_utils__get_cyclic_prefix, TestFixture) {
     }
 }
 
+BOOST_AUTO_TEST_SUITE_END()
+
 } /* namespace dji_droneid */
 } /* namespace gr */

gnuradio/gr-dji_droneid/lib/utils.cc

@@ -15,9 +15,6 @@
 namespace gr {
 namespace dji_droneid {
 
-utils::utils() {}
-
-utils::~utils() {}
 std::vector<uint32_t> utils::get_data_carrier_indices(const float sample_rate)
 {
     const auto fft_size = get_fft_size(sample_rate);

gnuradio/gr-dji_droneid/python/dji_droneid/bindings/utils_python.cc

@@ -14,7 +14,7 @@
 /* BINDTOOL_GEN_AUTOMATIC(0)                                                       */
 /* BINDTOOL_USE_PYGCCXML(0)                                                        */
 /* BINDTOOL_HEADER_FILE(utils.h)                                        */
-/* BINDTOOL_HEADER_FILE_HASH(5d705b1f8dd1119e4d23e6638798b4ed)                     */
+/* BINDTOOL_HEADER_FILE_HASH(341b0421657c63a408a05e68560d4ff8)                     */
 /***********************************************************************************/
 
 #include <pybind11/complex.h>

matlab/updated_scripts/create_zc.m

@@ -20,14 +20,9 @@ function [samples] = create_zc(fft_size, symbol_index)
     else
         root = 147;
     end
-
-    root
     
     % Would use MATLAB's zadoffChuSeq function, but Octave doesn't have that
     % The logic below was tested against the MATLAB function
-%     vals = pi * root * (0:600) .* (1:601) / 601;
-%     zc = cos(vals) + (1j * sin(vals));
-
     zc = reshape(exp(-1j * pi * root * (0:600) .* (1:601) / 601), [], 1);
     
     % Remove the middle value (this would be DC in the FFT)