added ScaledTranspose and started channeliser

psrdada_cpp/effelsberg/edd/Channeliser.cuh

+#ifndef PSRDADA_CPP_EFFELSBERG_EDD_CHANNELISER_HPP
+#define PSRDADA_CPP_EFFELSBERG_EDD_CHANNELISER_HPP
+
+#include "psrdada_cpp/effelsberg/edd/Unpacker.cuh"
+#include "psrdada_cpp/effelsberg/edd/DetectorAccumulator.cuh"
+#include "psrdada_cpp/raw_bytes.hpp"
+#include "psrdada_cpp/double_device_buffer.cuh"
+#include "psrdada_cpp/double_host_buffer.cuh"
+#include "thrust/device_vector.h"
+#include "cufft.h"
+
+namespace psrdada_cpp {
+namespace effelsberg {
+namespace edd {
+
+template <class HandlerType>
+class Channeliser
+{
+public:
+    typedef uint64_t RawVoltageType;
+    typedef float UnpackedVoltageType;
+    typedef float2 ChannelisedVoltageType;
+    typedef char2 PackedChannelisedVoltageType;
+
+public:
+    Channeliser(
+        std::size_t buffer_bytes,
+        std::size_t fft_length,
+        std::size_t nbits,
+        float input_level,
+        float output_level,
+        HandlerType& handler);
+    ~Channeliser();
+
+    /**
+     * @brief      A callback to be called on connection
+     *             to a ring buffer.
+     *
+     * @detail     The first available header block in the
+     *             in the ring buffer is provided as an argument.
+     *             It is here that header parameters could be read
+     *             if desired.
+     *
+     * @param      block  A RawBytes object wrapping a DADA header buffer
+     */
+    void init(RawBytes& block);
+
+    /**
+     * @brief      A callback to be called on acqusition of a new
+     *             data block.
+     *
+     * @param      block  A RawBytes object wrapping a DADA data buffer
+     */
+    bool operator()(RawBytes& block);
+
+private:
+    void process(thrust::device_vector<RawVoltageType> const& digitiser_raw,
+        thrust::device_vector<PackedChannelisedVoltageType>& packed_channelised);
+
+private:
+    std::size_t _buffer_bytes;
+    std::size_t _fft_length;
+    std::size_t _nbits;
+    HandlerType& _handler;
+    cufftHandle _fft_plan;
+    int _nchans;
+    int _call_count;
+    std::unique_ptr<Unpacker> _unpacker;
+    std::unique_ptr<DetectorAccumulator> _detector;
+    DoubleDeviceBuffer<RawVoltageType> _raw_voltage_db;
+    DoubleDeviceBuffer<PackedChannelisedVoltageType> _packed_channelised_voltage;
+    thrust::device_vector<UnpackedVoltageType> _unpacked_voltage;
+    thrust::device_vector<ChannelisedVoltageType> _channelised_voltage;
+    DoublePinnedHostBuffer<PackedChannelisedVoltageType> _host_packed_channelised_voltage;
+    cudaStream_t _h2d_stream;
+    cudaStream_t _proc_stream;
+    cudaStream_t _d2h_stream;
+};
+
+
+} //edd
+} //effelsberg
+} //psrdada_cpp
+
+#include "psrdada_cpp/effelsberg/edd/detail/Channeliser.cu"
+#endif //PSRDADA_CPP_EFFELSBERG_EDD_CHANNELISER_HPP

psrdada_cpp/effelsberg/edd/FftSpectrometer.cuh

-#ifndef PSRDADA_CPP_EFFELSBERG_EDD_FftSpectrometer_HPP
-#define PSRDADA_CPP_EFFELSBERG_EDD_FftSpectrometer_HPP
+#ifndef PSRDADA_CPP_EFFELSBERG_EDD_FFTSPECTROMETER_HPP
+#define PSRDADA_CPP_EFFELSBERG_EDD_FFTSPECTROMETER_HPP
 
 #include "psrdada_cpp/effelsberg/edd/Unpacker.cuh"
 #include "psrdada_cpp/effelsberg/edd/DetectorAccumulator.cuh"
@@ -85,4 +85,4 @@ private:
 } //psrdada_cpp
 
 #include "psrdada_cpp/effelsberg/edd/detail/FftSpectrometer.cu"
-#endif //PSRDADA_CPP_EFFELSBERG_EDD_FftSpectrometer_HPP
+#endif //PSRDADA_CPP_EFFELSBERG_EDD_FFTSPECTROMETER_HPP

psrdada_cpp/effelsberg/edd/ScaledTransposeTFtoTFT.cuh

+#ifndef PSRDADA_CPP_EFFELSBERG_EDD_SCALEDTRANSPOSETFTOTFT_CUH
+#define PSRDADA_CPP_EFFELSBERG_EDD_SCALEDTRANSPOSETFTOTFT_CUH
+
+#include "psrdada_cpp/common.hpp"
+#include <thrust/device_vector.h>
+
+namespace psrdada_cpp {
+namespace effelsberg {
+namespace edd {
+namespace kernels {
+
+__global__
+void tf_to_tft_transpose(
+    float2 const* __restrict__ input, 
+    char2* __restrict__ output, 
+    const int nchans, 
+    const int nsamps, 
+    const int nsamps_per_packet,
+    const int nsamps_per_load,
+    const float scale,
+    const float offset);
+
+} // namespace kernels
+
+class ScaledTransposeTFtoTFT
+{
+public:
+    typedef thrust::device_vector<float2> InputType;
+    typedef thrust::device_vector<char2> OutputType;
+
+public:
+    ScaledTransposeTFtoTFT(int nchans, int nsamps_per_packet, float scale, float offset, cudaStream_t stream);
+    ~ScaledTransposeTFtoTFT();
+    ScaledTransposeTFtoTFT(ScaledTransposeTFtoTFT const&) = delete;
+    void transpose(InputType const& input, OutputType& output);
+
+private:
+    int _nchans;
+    int _nsamps_per_packet;
+    float _scale;
+    float _offset;
+    cudaStream_t _stream;
+};
+
+} //namespace edd
+} //namespace effelsberg
+} //namespace psrdada_cpp
+
+#endif // PSRDADA_CPP_EFFELSBERG_EDD_SCALEDTRANSPOSETFTOTFT_CUH
+
+
+

psrdada_cpp/effelsberg/edd/detail/Channeliser.cu

+#include "psrdada_cpp/effelsberg/edd/Channeliser.cuh"
+#include "psrdada_cpp/common.hpp"
+#include "psrdada_cpp/cuda_utils.hpp"
+#include "psrdada_cpp/raw_bytes.hpp"
+#include "thrust/functional.h"
+#include "thrust/transform.h"
+#include <cuda.h>
+
+namespace psrdada_cpp {
+namespace effelsberg {
+namespace edd {
+
+template <class HandlerType>
+Channeliser<HandlerType>::Channeliser(
+    std::size_t buffer_bytes,
+    std::size_t fft_length,
+    std::size_t nbits,
+    float input_level,
+    float output_level,
+    HandlerType& handler)
+    : _buffer_bytes(buffer_bytes)
+    , _fft_length(fft_length)
+    , _nbits(nbits)
+    , _handler(handler)
+    , _fft_plan(0)
+    , _call_count(0)
+{
+
+    assert(((_nbits == 12) || (_nbits == 8)));
+    BOOST_LOG_TRIVIAL(debug)
+    << "Creating new Channeliser instance with parameters: \n"
+    << "fft_length = " << _fft_length << "\n"
+    << "naccumulate = " << _naccumulate;
+    std::size_t nsamps_per_buffer = buffer_bytes * 8 / nbits;
+    assert(nsamps_per_buffer % _fft_length == 0 /*Number of samples is not multiple of FFT size*/);
+    std::size_t n64bit_words = buffer_bytes / sizeof(uint64_t);
+    _nchans = _fft_length / 2 + 1;
+    int batch = nsamps_per_buffer/_fft_length;
+    BOOST_LOG_TRIVIAL(debug) << "Calculating scales and offsets";
+    float scale = std::sqrt(_nchans) * input_level;
+    BOOST_LOG_TRIVIAL(debug) << "Correction factors for 8-bit conversion: offset = " << offset << ", scaling = " << scaling;
+    BOOST_LOG_TRIVIAL(debug) << "Generating FFT plan";
+    int n[] = {static_cast<int>(_fft_length)};
+    //Not we put this into transposed output order, so the inner dimension will be time.
+    CUFFT_ERROR_CHECK(cufftPlanMany(&_fft_plan, 1, n, NULL, 1, _fft_length,
+        NULL, 1, _nchans, CUFFT_R2C, batch));
+    cufftSetStream(_fft_plan, _proc_stream);
+    BOOST_LOG_TRIVIAL(debug) << "Allocating memory";
+    _raw_voltage_db.resize(n64bit_words);
+    BOOST_LOG_TRIVIAL(debug) << "Input voltages size (in 64-bit words): " << _raw_voltage_db.size();
+    _unpacked_voltage.resize(nsamps_per_buffer);
+    BOOST_LOG_TRIVIAL(debug) << "Unpacked voltages size (in samples): " << _unpacked_voltage.size();
+    _channelised_voltage.resize(_nchans * batch);
+    BOOST_LOG_TRIVIAL(debug) << "Channelised voltages size: " << _channelised_voltage.size();
+    _packed_channelised_voltage.resize(_channelised_voltage.size());
+    BOOST_LOG_TRIVIAL(debug) << "Packed channelised voltages size: " << _packed_channelised_voltage.size();
+    _host_packed_channelised_voltage.resize(_packed_channelised_voltage.size());
+    CUDA_ERROR_CHECK(cudaStreamCreate(&_h2d_stream));
+    CUDA_ERROR_CHECK(cudaStreamCreate(&_proc_stream));
+    CUDA_ERROR_CHECK(cudaStreamCreate(&_d2h_stream));
+    CUFFT_ERROR_CHECK(cufftSetStream(_fft_plan, _proc_stream));
+    _unpacker.reset(new Unpacker(_proc_stream));
+}
+
+template <class HandlerType>
+Channeliser<HandlerType>::~Channeliser()
+{
+    BOOST_LOG_TRIVIAL(debug) << "Destroying Channeliser";
+    if (!_fft_plan)
+        cufftDestroy(_fft_plan);
+    cudaStreamDestroy(_h2d_stream);
+    cudaStreamDestroy(_proc_stream);
+    cudaStreamDestroy(_d2h_stream);
+}
+
+template <class HandlerType>
+void Channeliser<HandlerType>::init(RawBytes& block)
+{
+    BOOST_LOG_TRIVIAL(debug) << "Channeliser init called";
+    _handler.init(block);
+}
+
+template <class HandlerType>
+void Channeliser<HandlerType>::process(
+    thrust::device_vector<RawVoltageType> const& digitiser_raw,
+    thrust::device_vector<PackedChannelisedVoltageType>& packed_channelised))
+{
+    BOOST_LOG_TRIVIAL(debug) << "Unpacking raw voltages";
+    switch (_nbits)
+    {
+        case 8:  _unpacker->unpack<8>(digitiser_raw, _unpacked_voltage); break;
+        case 12: _unpacker->unpack<12>(digitiser_raw, _unpacked_voltage); break;
+        default: throw std::runtime_error("Unsupported number of bits");
+    }
+    BOOST_LOG_TRIVIAL(debug) << "Performing FFT";
+    UnpackedVoltageType* _unpacked_voltage_ptr = thrust::raw_pointer_cast(_unpacked_voltage.data());
+    ChannelisedVoltageType* _channelised_voltage_ptr = thrust::raw_pointer_cast(_channelised_voltage.data());
+    CUFFT_ERROR_CHECK(cufftExecR2C(_fft_plan,
+        (cufftReal*) _unpacked_voltage_ptr,
+        (cufftComplex*) _channelised_voltage_ptr));
+    CUDA_ERROR_CHECK(cudaStreamSynchronize(_proc_stream));
+    
+
+
+}
+
+template <class HandlerType>
+bool Channeliser<HandlerType>::operator()(RawBytes& block)
+{
+    ++_call_count;
+    BOOST_LOG_TRIVIAL(debug) << "Channeliser operator() called (count = " << _call_count << ")";
+    assert(block.used_bytes() == _buffer_bytes /* Unexpected buffer size */);
+
+    CUDA_ERROR_CHECK(cudaStreamSynchronize(_h2d_stream));
+    _raw_voltage_db.swap();
+
+    CUDA_ERROR_CHECK(cudaMemcpyAsync(static_cast<void*>(_raw_voltage_db.a_ptr()),
+        static_cast<void*>(block.ptr()), block.used_bytes(),
+        cudaMemcpyHostToDevice, _h2d_stream));
+
+    if (_call_count == 1)
+    {
+        return false;
+    }
+
+    // Synchronize all streams
+    CUDA_ERROR_CHECK(cudaStreamSynchronize(_proc_stream));
+    _power_db.swap();
+    process(_raw_voltage_db.b(), _power_db.a());
+
+    if (_call_count == 2)
+    {
+        return false;
+    }
+
+    CUDA_ERROR_CHECK(cudaStreamSynchronize(_d2h_stream));
+    _host_power_db.swap();
+    CUDA_ERROR_CHECK(cudaMemcpyAsync(
+        static_cast<void*>(_host_power_db.a_ptr()),
+        static_cast<void*>(_power_db.b_ptr()),
+        _power_db.size() * sizeof(IntegratedPowerType),
+        cudaMemcpyDeviceToHost,
+        _d2h_stream));
+    
+    if (_call_count == 3)
+    {
+        return false;
+    }   
+
+    //Wrap _detected_host_previous in a RawBytes object here;
+    RawBytes bytes(reinterpret_cast<char*>(_host_power_db.b_ptr()),
+        _host_power_db.size() * sizeof(IntegratedPowerType),
+        _host_power_db.size() * sizeof(IntegratedPowerType));
+    BOOST_LOG_TRIVIAL(debug) << "Calling handler";
+    // The handler can't do anything asynchronously without a copy here 
+    // as it would be unsafe (given that it does not own the memory it 
+    // is being passed).
+    return _handler(bytes);
+}
+
+} //edd
+} //effelsberg
+} //psrdada_cpp
+
+

psrdada_cpp/effelsberg/edd/detail/FftSpectrometer.cu

@@ -45,7 +45,7 @@ FftSpectrometer<HandlerType>::FftSpectrometer(
     BOOST_LOG_TRIVIAL(debug) << "Generating FFT plan";
     int n[] = {static_cast<int>(_fft_length)};
     CUFFT_ERROR_CHECK(cufftPlanMany(&_fft_plan, 1, n, NULL, 1, _fft_length,
-        NULL, 1, _fft_length/2 + 1, CUFFT_R2C, batch));
+        NULL, 1, _nchans, CUFFT_R2C, batch));
     cufftSetStream(_fft_plan, _proc_stream);
     BOOST_LOG_TRIVIAL(debug) << "Allocating memory";
     _raw_voltage_db.resize(n64bit_words);

psrdada_cpp/effelsberg/edd/src/ScaledTransposeTFtoTFT.cu

+#include "psrdada_cpp/effelsberg/edd/ScaledTransposeTFtoTFT.cuh"
+#include "psrdada_cpp/cuda_utils.hpp"
+
+namespace psrdada_cpp {
+namespace effelsberg {
+namespace edd {
+namespace kernels {
+
+__global__
+void tf_to_tft_transpose(
+    float2 const* __restrict__ input, 
+    char2* __restrict__ output, 
+    const int nchans, 
+    const int nsamps, 
+    const int nsamps_per_packet,
+    const int nsamps_per_load,
+    const float scale,
+    const float offset)
+{
+    extern __shared__ char2* temp; //nbytes = sizeof(char2) * nsamps_per_load * nchans;
+    const int load_offset = nsamps_per_packet * blockIdx.x * nchans;
+    for (int sub_samp_load_idx = 0;
+        sub_samp_load_idx < nsamps_per_packet/nsamps_per_load;
+        ++sub_samp_load_idx)
+    {
+        for (int samp_load_idx = threadIdx.y;
+            samp_load_idx < nsamps_per_load;
+            samp_load_idx += blockDim.y)
+        {
+            for (int chan_load_idx = threadIdx.x; 
+                chan_load_idx < nchans;
+                chan_load_idx += blockDim.x)
+            {
+                int load_idx = (load_offset + (sub_samp_load_idx * nsamps_per_load 
+                    + samp_load_idx) * nchans + chan_load_idx);
+                float2 val = input[load_idx];
+                char2 store_val;
+                store_val.x = (char)((val.x - offset)/scale);
+                store_val.y = (char)((val.y - offset)/scale);
+                temp[samp_load_idx * nsamps_per_load + chan_load_idx] = store_val;
+            }
+        }
+        __syncthreads();
+        int store_offset = load_offset + nsamps_per_load * sub_samp_load_idx;
+        for (int chan_store_idx = threadIdx.y;
+            chan_store_idx < nchans;
+            chan_store_idx += blockDim.y)
+        {
+            for (int samp_store_idx = threadIdx.x;
+                samp_store_idx < nsamps_per_load;
+                samp_store_idx += blockDix.x)
+            {
+                int store_idx = (load_offset + chan_store_idx * nsamps_per_packet 
+                    + samps_per_load * sub_samp_load_idx + samp_store_idx);
+                output[store_idx] = temp[samp_store_idx * nsamps_per_load + chan_store_idx];
+            }
+        }
+        __syncthreads();
+    }
+}
+
+} //namespace kernels
+
+ScaledTransposeTFtoTFT::ScaledTransposeTFtoTFT(
+    int nchans, int nsamps_per_packet, 
+    float scale, float offset, cudaStream_t stream)
+    : _nchans(nchans)
+    , _nsamps_per_packet(nsamps_per_packet)
+    , _scale(scale)
+    , _offset(offset)
+    , _stream(stream)
+{
+
+}
+
+ScaledTransposeTFtoTFT::~ScaledTransposeTFtoTFT()
+{
+
+}
+
+void ScaledTransposeTFtoTFT::transpose(InputType const& input, OutputType& output)
+{
+
+    const int max_threads = 1024;
+    const int dim_x = std::min(_nchans, max_threads);
+    const int dim_y = max_threads/dim_x;
+    //assert sizes
+    assert(input.size() % (_nchans * _nsamps_per_packet) == 0 /* Input is not a multiple of _nchans * _nsamps_per_packet*/);
+    output.resize(input.size());
+    const int nsamps_per_load = 16;
+    assert(_nsamps_per_packet % nsamps_per_load) == 0;
+    const int nsamps = input.size() / _nchans;
+    int shared_mem_bytes = sizeof(OutputType::value_type) * _nchans * nsamps_per_load;
+    int nblocks = nsamps / _nsamps_per_packet;
+    dim3 grid(nblocks);
+    dim3 block(dim_x, dim_y);
+    InputType::value_type const* input_ptr = thrust::raw_pointer_cast(input.data());
+    OutputType::value_type* output_ptr = thrust::raw_pointer_cast(output.data());
+    kernels::tf_to_tft_transpose<<<grid, block, shared_mem_bytes, _stream>>>(
+        input_ptr, output_ptr, _nchans, nsamps, _nsamps_per_packet, nsamps_per_load, _scale, _offset);
+    CUDA_ERROR_CHECK(cudaStreamSynchronize(_stream));
+}
+
+} //namespace edd
+} //namespace effelsberg
+} //namespace psrdada_cpp

psrdada_cpp/effelsberg/edd/test/CMakeLists.txt

@@ -4,9 +4,10 @@ link_directories(${GTEST_LIBRARY_DIR})
 
 set(
     gtest_edd_src
-    src/UnpackerTester.cu
     src/DetectorAccumulatorTester.cu
     src/FftSpectrometerTester.cu
+    src/UnpackerTester.cu
+    src/ScaledTransposeTFtoTFT.cu
 )
 cuda_add_executable(gtest_edd ${gtest_edd_src} )
 target_link_libraries(gtest_edd ${PSRDADA_CPP_EFFELSBERG_EDD_LIBRARIES} ${CUDA_CUFFT_LIBRARIES})

psrdada_cpp/effelsberg/edd/test/ScaledTransposeTFtoTFTTester.cuh

+#ifndef PSRDADA_CPP_EFFELSBERG_EDD_SCALEDTRANSPOSETFTOTFTTESTER_CUH
+#define PSRDADA_CPP_EFFELSBERG_EDD_SCALEDTRANSPOSETFTOTFTTESTER_CUH
+
+#include "psrdada_cpp/effelsberg/edd/ScaledTransposeTFtoTFT.cuh"
+#include "thrust/host_vector.h"
+#include <gtest/gtest.h>
+#include <vector>
+
+namespace psrdada_cpp {
+namespace effelsberg {
+namespace edd {
+namespace test {
+
+class ScaledTransposeTFtoTFTTester: public ::testing::Test
+{
+public:
+    typedef thrust::host_vector<float2> InputType;
+    typedef thrust::host_vector<char2> OutputType;
+
+protected:
+    void SetUp() override;
+    void TearDown() override;
+
+public:
+    ScaledTransposeTFtoTFTTester();
+    ~ScaledTransposeTFtoTFTTester();
+
+protected:
+    void transpose_c_reference(
+        InputType const& input,
+        OutputType& output,
+        const int nchans, 
+        const int nsamps, 
+        const int nsamps_per_packet,
+        const float scale,
+        const float offset);
+
+    void compare_against_host(
+        ScaledTransposeTFtoTFT::OutputType const& gpu_output,
+        OutputType const& host_output);
+
+protected:
+    cudaStream_t _stream;
+};
+
+} //namespace test
+} //namespace edd
+} //namespace meerkat
+} //namespace psrdada_cpp
+
+#endif //PSRDADA_CPP_EFFELSBERG_EDD_SCALEDTRANSPOSETFTOTFTTESTER_CUH

psrdada_cpp/effelsberg/edd/test/src/ScaledTransposeTFtoTFTTester.cu

+#include "psrdada_cpp/effelsberg/edd/test/ScaledTransposeTFtoTFTTester.cuh"
+#include "psrdada_cpp/cuda_utils.hpp"
+#include <random>
+#include <cmath>
+
+namespace psrdada_cpp {
+namespace effelsberg {
+namespace edd {
+namespace test {
+
+ScaledTransposeTFtoTFTTester::ScaledTransposeTFtoTFTTester()
+    : ::testing::Test()
+    , _stream(0)
+{
+
+}
+
+ScaledTransposeTFtoTFTTester::~ScaledTransposeTFtoTFTTester()
+{
+
+}
+
+void ScaledTransposeTFtoTFTTester::SetUp()
+{
+    CUDA_ERROR_CHECK(cudaStreamCreate(&_stream));
+}
+
+void ScaledTransposeTFtoTFTTester::TearDown()
+{
+    CUDA_ERROR_CHECK(cudaStreamDestroy(_stream));
+}
+
+void ScaledTransposeTFtoTFTTester::transpose_c_reference(
+        InputType const& input,
+        OutputType& output,
+        const int nchans, 
+        const int nsamps, 
+        const int nsamps_per_packet,
+        const float scale,
+        const float offset);
+{
+    int nsamples = input.size() / nchans;
+    int outer_t_dim = nsamps / nsamps_per_packet;
+    output.size(input.size());
+    for (int outer_t_idx = 0; outer_t_idx < outer_t_dim; ++outer_t_idx)
+    {
+        for (int chan_idx = 0; chan_idx < nchans; ++chan_idx)
+        {
+            for (int inner_t_idx = 0; inner_t_idx < nsamps_per_packet; ++inner_t_idx)
+            {
+                int load_idx = outer_t_idx * nchans * nsamps_per_packet + inner_t_idx * nchans + chan_idx;
+                float2 val = input[load_idx];
+                char2 out_val;
+                out_val.x = (char)((val.x - offset)/scale);
+                out_val.y = (char)((val.y - offset)/scale);
+                int store_idx = outer_t_idx * nchans * nsamps_per_packet + chan_idx * nsamps_per_packet + inner_t_idx;
+                output[store_idx] = out_val;
+            }
+        }
+    }
+}
+
+void ScaledTransposeTFtoTFTTester::compare_against_host(
+    ScaledTransposeTFtoTFT::OutputType const& gpu_output,
+    OutputType const& host_output)
+{
+    OutputType copy_from_gpu = gpu_output;
+    ASSERT_EQ(host_output.size(), copy_from_gpu.size());
+    for (std::size_t ii = 0; ii < host_output.size(); ++ii)
+    {
+	ASSERT_EQ(host_output[ii], copy_from_gpu[ii]);
+    }
+}
+
+TEST_F(ScaledTransposeTFtoTFTTester, counter_test)
+{
+    int nchans = 16;
+    int nsamps_per_packet = 8192/nchans;
+    float stdev = 64.0f;
+    float scale = 4.0f;
+    int nsamps = nsamps_per_packet * 1024
+    int n = nchans * nsamps;
+    std::default_random_engine generator;
+    std::normal_distribution<float> distribution(0.0, stdev);
+    InputType host_input(n);
+    for (int ii = 0; ii < n; ++ii)
+    {
+        host_input[ii].x = distribution(generator);
+	    host_input[ii].y = distribution(generator);
+    }
+    ScaledTransposeTFtoTFT::InputType gpu_input = host_input;
+    ScaledTransposeTFtoTFT::OutputType gpu_output;
+    OutputType host_output;
+    ScaledTransposeTFtoTFT transposer(nchans, nsamps_per_packet, nscale, 0.0, _stream);
+    transposer.transpose(gpu_input, gpu_output);
+    detect_c_reference(host_input, host_output, nchans, nsamps, nsamps_per_packet, scale, 0.0);
+    compare_against_host(gpu_output, host_output);
+}
+
+} //namespace test
+} //namespace edd
+} //namespace meerkat
+} //namespace psrdada_cpp