transforms.cpp
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#ifndef _MSC_VER
# include <itpp/config.h>
#else
# include <itpp/config_msvc.h>
#endif
#if defined(HAVE_FFT_MKL)
#include <stdio.h>
#include <stdlib.h>
namespace mkl
{
# include <mkl_dfti.h>
# include <mkl_service.h>
# undef DftiCreateDescriptor
}
#elif defined(HAVE_FFT_ACML)
namespace acml
{
# include <acml.h>
}
#elif defined(HAVE_FFTW3)
# include <fftw3.h>
#endif
#include <itpp/signal/transforms.h>
//multithreading mode selector
enum MultithreadingTag {SingleThreaded = 1, OmpThreaded};
#ifdef _OPENMP
#include <omp.h>
static const MultithreadingTag ThreadingTag = OmpThreaded;
//number of context records kept per transform type
//see comments for Transform_Provider class for futher details
static const int contexts_per_transform_type = 10;
//specialize mutex for multi-threaded code with OMP
class Mutex
{
omp_lock_t _lck;
//disable copy-construction and assignment
Mutex(const Mutex&);
Mutex& operator=(const Mutex&);
public:
Mutex() {omp_init_lock(&_lck);}
~Mutex() {omp_destroy_lock(&_lck);}
//lock the mutex
void lock() {omp_set_lock(&_lck);}
//try to lock. returns true if ownership is taken
bool try_lock() {return (omp_test_lock(&_lck)) != 0;}
//unlock
void unlock() {omp_unset_lock(&_lck);}
};
#else
static const MultithreadingTag ThreadingTag = SingleThreaded;
//number of context records kept per transform type
//see comments for Transform_Provider class for futher details
static const int contexts_per_transform_type = 1;
//specialize mutex for single-threaded code
class Mutex
{
//disable copy-construction and assignment
Mutex(const Mutex&);
Mutex& operator=(const Mutex&);
public:
Mutex() {}
~Mutex() {}
void lock() {}
bool try_lock() {return true;}
void unlock() {}
};
#endif
//mutex-based lock
class Lock
{
Mutex& _m;
//disable copy-construction and assignment
Lock(const Lock&);
Lock& operator=(const Lock&);
public:
Lock(Mutex& m): _m(m) {_m.lock();}
~Lock() {_m.unlock();}
};
namespace itpp
{
//define traits for all supported transform types: FFT complex, FFT real, IFFT Complex, IFFT Real, DCT, IDCT
struct FFTCplx_Traits {
typedef cvec InType;
typedef cvec OutType;
};
struct IFFTCplx_Traits {
typedef cvec InType;
typedef cvec OutType;
};
struct FFTReal_Traits {
typedef vec InType;
typedef cvec OutType;
};
struct IFFTReal_Traits {
typedef cvec InType;
typedef vec OutType;
};
struct DCT_Traits {
typedef vec InType;
typedef vec OutType;
};
struct IDCT_Traits {
typedef vec InType;
typedef vec OutType;
};
//generic transforms implementation based on transform type and specific FFT library
template<typename TransformTraits> class Transform;
//FFT library initializer based on mutithreading model
template<MultithreadingTag> inline void init_fft_library();
#if defined(HAVE_FFT_MKL)
//MKL-specific implementations
//MKL FFT-related notes:
//If multithreading is enabled on ITPP level (and in user's code) MKL FFT descriptors can be created, committed and freed by multiple threads
//In this case Intel recommends to use single-threaded FFT implementation:
//1. "Intel® MKL 10.x threading", http://software.intel.com/en-us/articles/intel-mkl-10x-threading,
//2. "Examples of Using Multi-Threading for FFT Computation", http://software.intel.com/sites/products/documentation/hpc/mkl/mklman/GUID-00422EBE-93C3-4BC9-A621-9BF0A0E93888.htm
//Based on examples, provided by Intel, it seems to be safe to create/commit/free and run FFT on per-thread descriptor
//without additional locking
template<> inline void init_fft_library<SingleThreaded>() {} //assume no actions required. ITPP does not use threading, so FFT library is free to use it's own threading implementation
template<> inline void init_fft_library<OmpThreaded>()
{
//switch FFT domain of MKL to single-threaded mode as Intel suggests
//this should work starting from MKL 10.0
mkl::mkl_domain_set_num_threads(1, MKL_FFT);
}
//---------------------------------------------------------------------------
// FFT/IFFT based on MKL
//---------------------------------------------------------------------------
inline void release_descriptor(mkl::DFTI_DESCRIPTOR* h)
{
if(h != NULL) {
MKL_LONG status = mkl::DftiFreeDescriptor(&h);
if(status) {
it_info(mkl::DftiErrorMessage(status));
it_error("MKL library release_descriptor() failed on DftiFreeDescriptor.");
}
}
}
template<> class Transform<FFTCplx_Traits>
{
mkl::DFTI_DESCRIPTOR* _h;
int _transform_length;
public:
Transform(): _h(NULL), _transform_length(0) {}
void compute_transform(const cvec &in, cvec &out) {
out.set_size(in.size(), false);
if(_transform_length != in.size()) {
release_descriptor(_h);
_transform_length = in.size();
MKL_LONG status = mkl::DftiCreateDescriptor(&_h, mkl::DFTI_DOUBLE, mkl::DFTI_COMPLEX, 1, _transform_length);
if(status) {
it_info(mkl::DftiErrorMessage(status));
it_error("MKL library compute_transform() failed on DftiCreateDescriptor.");
}
mkl::DftiSetValue(_h, mkl::DFTI_PLACEMENT, mkl::DFTI_NOT_INPLACE);
status = mkl::DftiCommitDescriptor(_h);
if(status) {
it_info(mkl::DftiErrorMessage(status));
it_error("MKL library compute_transform() failed on DftiCommitDescriptor.");
}
}
mkl::DftiComputeForward(_h, (void *)in._data(), out._data());
}
void reset() {release_descriptor(_h); *this = Transform();}
};
template<> class Transform<IFFTCplx_Traits>
{
mkl::DFTI_DESCRIPTOR* _h;
int _transform_length;
public:
Transform(): _h(NULL), _transform_length(0) {}
void compute_transform(const cvec &in, cvec &out) {
out.set_size(in.size(), false);
if(_transform_length != in.size()) {
release_descriptor(_h);
_transform_length = in.size();
MKL_LONG status = mkl::DftiCreateDescriptor(&_h, mkl::DFTI_DOUBLE, mkl::DFTI_COMPLEX, 1, _transform_length);
if(status) {
it_info(mkl::DftiErrorMessage(status));
it_error("MKL library compute_transform() failed on DftiCreateDescriptor.");
}
mkl::DftiSetValue(_h, mkl::DFTI_PLACEMENT, mkl::DFTI_NOT_INPLACE);
mkl::DftiSetValue(_h, mkl::DFTI_BACKWARD_SCALE, 1.0 / _transform_length);
status = mkl::DftiCommitDescriptor(_h);
if(status) {
it_info(mkl::DftiErrorMessage(status));
it_error("MKL library compute_transform() failed on DftiCommitDescriptor.");
}
}
mkl::DftiComputeBackward(_h, (void *)in._data(), out._data());
}
void reset() {release_descriptor(_h); *this = Transform();}
};
template<> class Transform<FFTReal_Traits>
{
mkl::DFTI_DESCRIPTOR* _h;
int _transform_length;
public:
Transform(): _h(NULL), _transform_length(0) {}
void compute_transform(const vec &in, cvec &out) {
out.set_size(in.size(), false);
if(_transform_length != in.size()) {
release_descriptor(_h);
_transform_length = in.size();
MKL_LONG status = mkl::DftiCreateDescriptor(&_h, mkl::DFTI_DOUBLE, mkl::DFTI_REAL, 1, _transform_length);
if(status) {
it_info(mkl::DftiErrorMessage(status));
it_error("MKL library compute_transform() failed on DftiCreateDescriptor.");
}
mkl::DftiSetValue(_h, mkl::DFTI_PLACEMENT, mkl::DFTI_NOT_INPLACE);
status = mkl::DftiCommitDescriptor(_h);
if(status) {
it_info(mkl::DftiErrorMessage(status));
it_error("MKL library compute_transform() failed on DftiCommitDescriptor.");
}
}
mkl::DftiComputeForward(_h, (void *)in._data(), out._data());
// Real FFT does not compute the 2nd half of the FFT points because it
// is redundant to the 1st half. However, we want all of the data so we
// fill it in. This is consistent with Matlab's functionality
int istart = ceil_i(in.size() / 2.0);
int idelta = in.size() - istart;
out.set_subvector(istart, reverse(conj(out(1, idelta))));
}
void reset() {release_descriptor(_h); *this = Transform();}
};
template<> class Transform<IFFTReal_Traits>
{
mkl::DFTI_DESCRIPTOR* _h;
int _transform_length;
public:
Transform(): _h(NULL), _transform_length(0) {}
void compute_transform(const cvec &in, vec &out) {
out.set_size(in.size(), false);
if(_transform_length != in.size()) {
release_descriptor(_h);
_transform_length = in.size();
MKL_LONG status = mkl::DftiCreateDescriptor(&_h, mkl::DFTI_DOUBLE, mkl::DFTI_REAL, 1, _transform_length);
if(status) {
it_info(mkl::DftiErrorMessage(status));
it_error("MKL library compute_transform() failed on DftiCreateDescriptor.");
}
mkl::DftiSetValue(_h, mkl::DFTI_PLACEMENT, mkl::DFTI_NOT_INPLACE);
mkl::DftiSetValue(_h, mkl::DFTI_BACKWARD_SCALE, 1.0 / _transform_length);
status = mkl::DftiCommitDescriptor(_h);
if(status) {
it_info(mkl::DftiErrorMessage(status));
it_error("MKL library compute_transform() failed on DftiCommitDescriptor.");
}
}
mkl::DftiComputeBackward(_h, (void *)in._data(), out._data());
}
void reset() {release_descriptor(_h); *this = Transform();}
};
#endif // #ifdef HAVE_FFT_MKL
#if defined(HAVE_FFT_ACML)
//ACML-specific implementations
//ACML FFT-related notes:
//ACML documentation is not very verbose regarding the multithreaded use of the library, but multithreaded ifort-built ACML uses
//OMP internally. AMD recommends linking with SINGLE-THREADED library if OMP is enabled in user's code. Also, they claim that
//single-threaded functions can be used from the multiple threads simultaniously (see http://devgurus.amd.com/thread/141592 for
//multi-threading discussion on AMD dev forums) The thread-safety of library functions is also mentioned in ACML release notes (ver 4.4.0).
//In the following implementation we assume that ACML transform functions can be run simultaneously from different threads safely if they operate
//on different data sets.
template<> inline void init_fft_library<SingleThreaded>() {} //assume no actions required.
template<> inline void init_fft_library<OmpThreaded>() {}
//---------------------------------------------------------------------------
// FFT/IFFT based on ACML
//---------------------------------------------------------------------------
template<> class Transform<FFTCplx_Traits>
{
cvec _scratchpad;
int _transform_length;
public:
Transform(): _transform_length(0) {}
void compute_transform(const cvec &in, cvec &out) {
int info;
out.set_size(in.size(), false);
if(_transform_length != in.size()) {
_transform_length = in.size();
int min_required_size = 5 * _transform_length + 100; //ACML guides suggest 3*size + 100 here, but ITPP code uses 5.
if(_scratchpad.size() < min_required_size) _scratchpad.set_size(min_required_size);
acml::zfft1dx(0, 1.0, false, _transform_length, (acml::doublecomplex *)in._data(), 1,
(acml::doublecomplex *)out._data(), 1,
(acml::doublecomplex *)_scratchpad._data(), &info);
}
acml::zfft1dx(-1, 1.0, false, _transform_length, (acml::doublecomplex *)in._data(), 1,
(acml::doublecomplex *)out._data(), 1,
(acml::doublecomplex *)_scratchpad._data(), &info);
}
void reset() {*this = Transform();}
};
template<> class Transform<IFFTCplx_Traits>
{
cvec _scratchpad;
int _transform_length;
public:
Transform(): _transform_length(0) {}
void compute_transform(const cvec &in, cvec &out) {
int info;
out.set_size(in.size(), false);
if(_transform_length != in.size()) {
_transform_length = in.size();
int min_required_size = 5 * _transform_length + 100; //ACML guides suggest 3*size + 100 here, but ITPP code uses 5.
if(_scratchpad.size() < min_required_size) _scratchpad.set_size(min_required_size);
acml::zfft1dx(0, 1.0 / _transform_length, false, _transform_length, (acml::doublecomplex *)in._data(), 1,
(acml::doublecomplex *)out._data(), 1,
(acml::doublecomplex *)_scratchpad._data(), &info);
}
acml::zfft1dx(1, 1.0 / _transform_length, false, _transform_length, (acml::doublecomplex *)in._data(), 1,
(acml::doublecomplex *)out._data(), 1,
(acml::doublecomplex *)_scratchpad._data(), &info);
}
void reset() {*this = Transform();}
};
template<> class Transform<FFTReal_Traits>
{
vec _scratchpad;
int _transform_length;
public:
Transform(): _transform_length(0) {}
void compute_transform(const vec &in, cvec &out) {
vec out_re = in;
int info;
if(_transform_length != in.size()) {
_transform_length = in.size();
int min_required_size = 5 * _transform_length + 100; //ACML guides suggest 3*size + 100 here, but ITPP code uses 5.
if(_scratchpad.size() < min_required_size) _scratchpad.set_size(min_required_size);
acml::dzfft(0, _transform_length, out_re._data(), _scratchpad._data(), &info);
}
acml::dzfft(1, _transform_length, out_re._data(), _scratchpad._data(), &info);
// Normalise output data
double factor = std::sqrt(static_cast<double>(_transform_length));
out_re *= factor;
// Convert the real Hermitian DZFFT's output to the Matlab's complex form
vec out_im(_transform_length);
out_im(0) = 0.0;
if(!(_transform_length % 2)) out_im(_transform_length / 2) = 0.0; //even transform length
out_im.set_subvector(1, reverse(out_re(_transform_length / 2 + 1, _transform_length - 1)));
out_im.set_subvector(_transform_length / 2 + 1, -out_re(_transform_length / 2 + 1, _transform_length - 1));
out_re.set_subvector(_transform_length / 2 + 1, reverse(out_re(1, (_transform_length - 1) / 2)));
out.set_size(_transform_length, false);
out = to_cvec(out_re, out_im);
}
void reset() {*this = Transform();}
};
template<> class Transform<IFFTReal_Traits>
{
vec _scratchpad;
int _transform_length;
public:
Transform(): _transform_length(0) {}
void compute_transform(const cvec &in, vec &out) {
// Convert Matlab's complex input to the real Hermitian form
out.set_size(in.size());
out.set_subvector(0, real(in(0, in.size() / 2)));
out.set_subvector(in.size() / 2 + 1, -imag(in(in.size() / 2 + 1, in.size() - 1)));
int info;
if(_transform_length != in.size()) {
_transform_length = in.size();
int min_required_size = 5 * _transform_length + 100; //ACML guides suggest 3*size + 100 here, but ITPP code uses 5.
if(_scratchpad.size() < min_required_size) _scratchpad.set_size(min_required_size);
acml::zdfft(0, _transform_length, out._data(), _scratchpad._data(), &info);
}
acml::zdfft(1, _transform_length, out._data(), _scratchpad._data(), &info);
out.set_subvector(1, reverse(out(1, _transform_length - 1)));
// Normalise output data
double factor = 1.0 / std::sqrt(static_cast<double>(_transform_length));
out *= factor;
}
void reset() {*this = Transform();}
};
#endif // defined(HAVE_FFT_ACML)
#if defined(HAVE_FFTW3)
//FFTW3-specific implementations
//FFTW3-related notes:
//Based on the FFtW3 documentation, it is thread-safe to call fftw_execute family functions simultaniously from several threads assuming that data sets are different in each thread.
//FFTW plans creation-destruction is not thread-safe and should be serialized by the caller. FFTW provides some functions to execute transforms with multiple threads (assuming FFTW
// is compiled and linked with multithreading support). Current ITPP implementation does not use any of them.
template<> inline void init_fft_library<SingleThreaded>() {} //assume no actions required.
template<> inline void init_fft_library<OmpThreaded>() {}
//define global lock for operations with FFTW plans.
Mutex& get_library_lock()
{
static Mutex FFTW3LibraryLock;
return FFTW3LibraryLock;
}
//---------------------------------------------------------------------------
// FFT/IFFT based on FFTW
//---------------------------------------------------------------------------
inline void destroy_plan(fftw_plan p)
{
if(p != NULL) fftw_destroy_plan(p); // destroy the plan
}
template<> class Transform<FFTCplx_Traits>
{
fftw_plan _p;
int _transform_length;
public:
Transform(): _p(NULL), _transform_length(0) {}
void compute_transform(const cvec &in, cvec &out) {
out.set_size(in.size(), false);
if(_transform_length != in.size()) {
Lock l(get_library_lock()); //apply global library lock on plan changes
_transform_length = in.size();
destroy_plan(_p); // destroy the previous plan
// create a new plan (creation of plan guarantees not to return NULL)
_p = fftw_plan_dft_1d(_transform_length, (fftw_complex *)in._data(),
(fftw_complex *)out._data(),
FFTW_FORWARD, FFTW_ESTIMATE);
}
//compute FFT using the GURU FFTW interface
fftw_execute_dft(_p, (fftw_complex *)in._data(),
(fftw_complex *)out._data());
}
void reset() {destroy_plan(_p); *this = Transform();}
};
template<> class Transform<IFFTCplx_Traits>
{
fftw_plan _p;
int _transform_length;
public:
Transform(): _p(NULL), _transform_length(0) {}
void compute_transform(const cvec &in, cvec &out) {
out.set_size(in.size(), false);
if(_transform_length != in.size()) {
Lock l(get_library_lock()); //apply global library lock on plan changes
_transform_length = in.size();
destroy_plan(_p); // destroy the previous plan
// create a new plan (creation of plan guarantees not to return NULL)
_p = fftw_plan_dft_1d(_transform_length, (fftw_complex *)in._data(),
(fftw_complex *)out._data(),
FFTW_BACKWARD, FFTW_ESTIMATE);
}
//compute FFT using the GURU FFTW interface
fftw_execute_dft(_p, (fftw_complex *)in._data(),
(fftw_complex *)out._data());
// scale output
double inv_N = 1.0 / _transform_length;
out *= inv_N;
}
void reset() {destroy_plan(_p); *this = Transform();}
};
template<> class Transform<FFTReal_Traits>
{
fftw_plan _p;
int _transform_length;
public:
Transform(): _p(NULL), _transform_length(0) {}
void compute_transform(const vec &in, cvec &out) {
out.set_size(in.size(), false);
if(_transform_length != in.size()) {
Lock l(get_library_lock()); //apply global library lock on plan changes
_transform_length = in.size();
destroy_plan(_p); // destroy the previous plan
// create a new plan (creation of plan guarantees not to return NULL)
_p = fftw_plan_dft_r2c_1d(_transform_length, (double *)in._data(),
(fftw_complex *)out._data(),
FFTW_ESTIMATE);
}
//compute FFT using the GURU FFTW interface
fftw_execute_dft_r2c(_p, (double *)in._data(),
(fftw_complex *)out._data());
// Real FFT does not compute the 2nd half of the FFT points because it
// is redundant to the 1st half. However, we want all of the data so we
// fill it in. This is consistent with Matlab's functionality
int offset = ceil_i(_transform_length / 2.0);
int n_elem = _transform_length - offset;
for(int i = 0; i < n_elem; ++i) {
out(offset + i) = std::conj(out(n_elem - i));
}
}
void reset() {destroy_plan(_p); *this = Transform();}
};
template<> class Transform<IFFTReal_Traits>
{
fftw_plan _p;
int _transform_length;
public:
Transform(): _p(NULL), _transform_length(0) {}
void compute_transform(const cvec &in, vec &out) {
out.set_size(in.size(), false);
if(_transform_length != in.size()) {
Lock l(get_library_lock()); //apply global library lock on plan changes
_transform_length = in.size();
destroy_plan(_p); // destroy the previous plan
// create a new plan (creation of plan guarantees not to return NULL)
_p = fftw_plan_dft_c2r_1d(_transform_length, (fftw_complex *)in._data(),
(double *)out._data(),
FFTW_ESTIMATE | FFTW_PRESERVE_INPUT);
}
//compute FFT using the GURU FFTW interface
fftw_execute_dft_c2r(_p, (fftw_complex *)in._data(),
(double *)out._data());
// scale output
double inv_N = 1.0 / _transform_length;
out *= inv_N;
}
void reset() {destroy_plan(_p); *this = Transform();}
};
//---------------------------------------------------------------------------
// DCT/IDCT based on FFTW
//---------------------------------------------------------------------------
template<> class Transform<DCT_Traits>
{
fftw_plan _p;
int _transform_length;
public:
Transform(): _p(NULL), _transform_length(0) {}
void compute_transform(const vec &in, vec &out) {
out.set_size(in.size(), false);
if(_transform_length != in.size()) {
Lock l(get_library_lock()); //apply global library lock on plan changes
_transform_length = in.size();
destroy_plan(_p); // destroy the previous plan
// create a new plan (creation of plan guarantees not to return NULL)
_p = fftw_plan_r2r_1d(_transform_length, (double *)in._data(),
(double *)out._data(),
FFTW_REDFT10, FFTW_ESTIMATE);
}
// compute FFT using the GURU FFTW interface
fftw_execute_r2r(_p, (double *)in._data(), (double *)out._data());
// Scale to matlab definition format
out /= std::sqrt(2.0 * _transform_length);
out(0) /= std::sqrt(2.0);
}
void reset() {destroy_plan(_p); *this = Transform();}
};
template<> class Transform<IDCT_Traits>
{
fftw_plan _p;
int _transform_length;
public:
Transform(): _p(NULL), _transform_length(0) {}
void compute_transform(const vec &in, vec &out) {
out = in;
// Rescale to FFTW format
out(0) *= std::sqrt(2.0);
out /= std::sqrt(2.0 * in.size());
if(_transform_length != in.size()) {
Lock l(get_library_lock()); //apply global library lock on plan changes
_transform_length = in.size();
destroy_plan(_p); // destroy the previous plan
// create a new plan (creation of plan guarantees not to return NULL)
_p = fftw_plan_r2r_1d(_transform_length, (double *)in._data(),
(double *)out._data(),
FFTW_REDFT01, FFTW_ESTIMATE);
}
// compute FFT using the GURU FFTW interface
fftw_execute_r2r(_p, (double *)out._data(), (double *)out._data());
}
void reset() {destroy_plan(_p); *this = Transform();}
};
#endif // defined(HAVE_FFTW3)
#if defined(HAVE_FFT_MKL) || defined(HAVE_FFT_ACML)
//---------------------------------------------------------------------------
// DCT/IDCT based on MKL or ACML
//---------------------------------------------------------------------------
//use FFT on real values to perform DCT
template<> class Transform<DCT_Traits>
{
Transform<FFTReal_Traits> _tr;
public:
Transform() {}
void compute_transform(const vec &in, vec &out) {
int N = in.size();
if(N == 1)
out = in;
else {
cvec c;
_tr.compute_transform(concat(in, reverse(in)), c);
c.set_size(N, true);
for(int i = 0; i < N; i++) {
c(i) *= std::complex<double>(std::cos(pi * i / N / 2), std::sin(-pi * i / N / 2))
/ std::sqrt(2.0 * N);
}
out = real(c);
out(0) /= std::sqrt(2.0);
}
}
void reset() {_tr.reset();}
};
//use IFFT with real output to perform IDCT
template<> class Transform<IDCT_Traits>
{
Transform<IFFTReal_Traits> _tr;
public:
Transform() {}
void compute_transform(const vec &in, vec &out) {
int N = in.size();
if(N == 1)
out = in;
else {
cvec c = to_cvec(in);
c.set_size(2 * N, true);
c(0) *= std::sqrt(2.0);
for(int i = 0; i < N; i++) {
c(i) *= std::complex<double>(std::cos(pi * i / N / 2), std::sin(pi * i / N / 2))
* std::sqrt(2.0 * N);
}
for(int i = N - 1; i >= 1; i--) {
c(c.size() - i) = c(i) * std::complex<double>(std::cos(pi * i / N),
std::sin(-pi * i / N));
}
_tr.compute_transform(c, out);
out.set_size(N, true);
}
}
void reset() {_tr.reset();}
};
#endif
#if defined(HAVE_FFT)
//lock-protected transform to serialize accesses to the context from several threads
template<typename TransformTraits> class Locked_Transform : private Transform<TransformTraits>
{
typedef Transform<TransformTraits> Base;
Mutex _m;
public:
Locked_Transform() {}
//release context
void release_context() {Lock l(_m); Base::reset();}
void run_transform(const typename TransformTraits::InType& in, typename TransformTraits::OutType& out) {Lock l(_m); Base::compute_transform(in, out);}
};
//Typical multithreaded application creates several threads upon entry to parallel region and join them upon exit from it.
//Threads used to perform parallel computations can either be terminated upon exit from the parallel region or left in the
//parked state, so in the next parallel region application can reuse already created threads from the team instead of the
//time-consuming creation of new threads. There is no way to control threads creation-destruction with OMP and, therefore
//there is no way to implement automatic clean-up of transform computation contexts for each thread (basically, this means that
//we can not appropriately release FFT library resources and this results in memory leak)
//In order to solve this problem and implement the FFT transforms in multithreded environment library relyes on the statically
//created pool of transform contexts.
//Each thread willing to run the transfrom queries the context index from transfrom provider. Thread uses assigned index and
//corresponding context to compute the transforms during it's lifetime. Provider assigns contexts in round-robbin fashion, so
//context used by the exited threads are reused by newly created ones.
//Single context can be reused by multiple threads if application created more then contexts_per_transform_type threads performing
//some type of transform.
static bool is_library_initialized = false;
template<typename TransformTraits> class Transform_Provider
{
typedef Locked_Transform<TransformTraits> Transform;
Transform _transforms[contexts_per_transform_type];
int _id;
public:
Transform_Provider(): _id(0) {
if(!is_library_initialized) {
//initialize FFT library on first conctruction of any of Transform_Provider objects
init_fft_library<ThreadingTag>();
is_library_initialized = true;
}
}
int get_context_id() {
//assign id in round-robin fashion.
int ret = _id + 1;
if(ret == contexts_per_transform_type)
_id = 0;
else
_id = ret;
return ret;
}
void run_transform(int id, const typename TransformTraits::InType& in, typename TransformTraits::OutType& out) {
_transforms[id - 1].run_transform(in, out);
}
//provider destructor. releases context resources.
//destructor is called after the main() exits, so there is no need to protect context release with mutex
~Transform_Provider() {
for(int i = 0; i < contexts_per_transform_type; ++i)
_transforms[i].release_context();
}
};
//Transform_Provider is constructed upon the first request
template<typename TransformTraits> Transform_Provider<TransformTraits>& get_transform_provider()
{
static Transform_Provider<TransformTraits> p;
return p;
}
void fft(const cvec &in, cvec &out)
{
static int context_id = 0;
#pragma omp threadprivate(context_id)
if(context_id == 0) {
//first-time transform call
#pragma omp critical
{
//serialize access to transform provider to get the id
context_id = get_transform_provider<FFTCplx_Traits>().get_context_id();
}
}
it_assert(in.size() > 0, "fft(): zero-sized input detected");
//there is no need to serialize here, since provider is constructed at this point
get_transform_provider<FFTCplx_Traits>().run_transform(context_id, in, out);
}
void ifft(const cvec &in, cvec &out)
{
static int context_id = 0;
#pragma omp threadprivate(context_id)
if(context_id == 0) {
//first-time transform call
#pragma omp critical
{
//serialize access to transform provider to get the id
context_id = get_transform_provider<IFFTCplx_Traits>().get_context_id();
}
}
it_assert(in.size() > 0, "ifft(): zero-sized input detected");
//there is no need to serialize here, since provider is constructed at this point
get_transform_provider<IFFTCplx_Traits>().run_transform(context_id, in, out);
}
void fft_real(const vec &in, cvec &out)
{
static int context_id = 0;
#pragma omp threadprivate(context_id)
if(context_id == 0) {
//first-time transform call
#pragma omp critical
{
//serialize access to transform provider to get the id
context_id = get_transform_provider<FFTReal_Traits>().get_context_id();
}
}
it_assert(in.size() > 0, "fft_real(): zero-sized input detected");
//there is no need to serialize here, since provider is constructed at this point
get_transform_provider<FFTReal_Traits>().run_transform(context_id, in, out);
}
void ifft_real(const cvec &in, vec &out)
{
static int context_id = 0;
#pragma omp threadprivate(context_id)
if(context_id == 0) {
//first-time transform call
#pragma omp critical
{
//serialize access to transform provider to get the id
context_id = get_transform_provider<IFFTReal_Traits>().get_context_id();
}
}
it_assert(in.size() > 0, "ifft_real(): zero-sized input detected");
//there is no need to serialize here, since provider is constructed at this point
get_transform_provider<IFFTReal_Traits>().run_transform(context_id, in, out);
}
void dct(const vec &in, vec &out)
{
static int context_id = 0;
#pragma omp threadprivate(context_id)
if(context_id == 0) {
//first-time transform call
#pragma omp critical
{
//serialize access to transform provider to get the id
context_id = get_transform_provider<DCT_Traits>().get_context_id();
}
}
it_assert(in.size() > 0, "dct(): zero-sized input detected");
//there is no need to serialize here, since provider is definitely constructed at this point
get_transform_provider<DCT_Traits>().run_transform(context_id, in, out);
}
void idct(const vec &in, vec &out)
{
static int context_id = 0;
#pragma omp threadprivate(context_id)
if(context_id == 0) {
//first-time transform call
#pragma omp critical
{
//serialize access to transform provider to get the id
context_id = get_transform_provider<IDCT_Traits>().get_context_id();
}
}
it_assert(in.size() > 0, "dct(): zero-sized input detected");
//there is no need to serialize here, since provider is definitely constructed at this point
get_transform_provider<IDCT_Traits>().run_transform(context_id, in, out);
}
bool have_fourier_transforms() {return true;}
bool have_cosine_transforms() {return true;}
#else
void fft(const cvec &in, cvec &out)
{
it_error("FFT library is needed to use fft() function");
}
void ifft(const cvec &in, cvec &out)
{
it_error("FFT library is needed to use ifft() function");
}
void fft_real(const vec &in, cvec &out)
{
it_error("FFT library is needed to use fft_real() function");
}
void ifft_real(const cvec &in, vec & out)
{
it_error("FFT library is needed to use ifft_real() function");
}
void dct(const vec &in, vec &out)
{
it_error("FFT library is needed to use dct() function");
}
void idct(const vec &in, vec &out)
{
it_error("FFT library is needed to use idct() function");
}
bool have_fourier_transforms() {return false;}
bool have_cosine_transforms() {return false;}
#endif // defined(HAVE_FFT)
cvec fft(const cvec &in)
{
cvec out;
fft(in, out);
return out;
}
cvec fft(const cvec &in, const int N)
{
cvec in2 = in;
cvec out;
in2.set_size(N, true);
fft(in2, out);
return out;
}
cvec ifft(const cvec &in)
{
cvec out;
ifft(in, out);
return out;
}
cvec ifft(const cvec &in, const int N)
{
cvec in2 = in;
cvec out;
in2.set_size(N, true);
ifft(in2, out);
return out;
}
cvec fft_real(const vec& in)
{
cvec out;
fft_real(in, out);
return out;
}
cvec fft_real(const vec& in, const int N)
{
vec in2 = in;
cvec out;
in2.set_size(N, true);
fft_real(in2, out);
return out;
}
vec ifft_real(const cvec &in)
{
vec out;
ifft_real(in, out);
return out;
}
vec ifft_real(const cvec &in, const int N)
{
cvec in2 = in;
in2.set_size(N, true);
vec out;
ifft_real(in2, out);
return out;
}
vec dct(const vec &in)
{
vec out;
dct(in, out);
return out;
}
vec dct(const vec &in, const int N)
{
vec in2 = in;
vec out;
in2.set_size(N, true);
dct(in2, out);
return out;
}
vec idct(const vec &in)
{
vec out;
idct(in, out);
return out;
}
vec idct(const vec &in, const int N)
{
vec in2 = in;
vec out;
in2.set_size(N, true);
idct(in2, out);
return out;
}
// ----------------------------------------------------------------------
// Instantiation
// ----------------------------------------------------------------------
template ITPP_EXPORT vec dht(const vec &v);
template ITPP_EXPORT cvec dht(const cvec &v);
template ITPP_EXPORT void dht(const vec &vin, vec &vout);
template ITPP_EXPORT void dht(const cvec &vin, cvec &vout);
template ITPP_EXPORT void self_dht(vec &v);
template ITPP_EXPORT void self_dht(cvec &v);
template ITPP_EXPORT vec dwht(const vec &v);
template ITPP_EXPORT cvec dwht(const cvec &v);
template ITPP_EXPORT void dwht(const vec &vin, vec &vout);
template ITPP_EXPORT void dwht(const cvec &vin, cvec &vout);
template ITPP_EXPORT void self_dwht(vec &v);
template ITPP_EXPORT void self_dwht(cvec &v);
template ITPP_EXPORT mat dht2(const mat &m);
template ITPP_EXPORT cmat dht2(const cmat &m);
template ITPP_EXPORT mat dwht2(const mat &m);
template ITPP_EXPORT cmat dwht2(const cmat &m);
} // namespace itpp
itpp::Array::set_size
void set_size(int n, bool copy=false)
Resizing an Array<T>.
Definition array.h:257
itpp::Array::concat
friend const Array< T > concat(const Array< T > &a1, const T &e)
Append element e to the end of the Array a.
Definition array.h:486
itpp::idct
ITPP_EXPORT void idct(const vec &in, vec &out)
Inverse Discrete Cosine Transform (IDCT)
itpp::dct
ITPP_EXPORT void dct(const vec &in, vec &out)
Discrete Cosine Transform (DCT)
itpp::have_cosine_transforms
ITPP_EXPORT bool have_cosine_transforms()
Run-time test if library is built with cosine transforms enabled.
it_error
#define it_error(s)
Abort unconditionally.
Definition itassert.h:126
it_info
#define it_info(s)
Print information message.
Definition itassert.h:136
it_assert
#define it_assert(t, s)
Abort if t is not true.
Definition itassert.h:94
itpp::ifft
ITPP_EXPORT void ifft(const cvec &in, cvec &out)
Inverse Fast Fourier Transform.
itpp::fft_real
ITPP_EXPORT void fft_real(const vec &in, cvec &out)
Real Fast Fourier Transform.
itpp::ifft_real
ITPP_EXPORT void ifft_real(const cvec &in, vec &out)
Inverse Real Fast Fourier Transform.
itpp::have_fourier_transforms
ITPP_EXPORT bool have_fourier_transforms()
Run-time test if library is built with Fast Fourier Transforms enabled.
itpp::fft
ITPP_EXPORT void fft(const cvec &in, cvec &out)
Fast Fourier Transform.
itpp::dwht2
Mat< T > dwht2(const Mat< T > &m)
Fast 2D Walsh Hadamard Transform.
Definition transforms.h:376
itpp::dwht
Vec< T > dwht(const Vec< T > &v)
Fast Walsh Hadamard Transform.
Definition transforms.h:333
itpp::dht
Vec< T > dht(const Vec< T > &v)
Fast Hadamard Transform.
Definition transforms.h:243
itpp::self_dht
void self_dht(Vec< T > &v)
Fast Hadamard Transform - memory efficient. Stores the result in v.
Definition transforms.h:307
itpp::dht2
Mat< T > dht2(const Mat< T > &m)
Fast 2D Hadamard Transform.
Definition transforms.h:356
itpp::self_dwht
void self_dwht(Vec< T > &v)
Fast Walsh Hadamard Transform - memory efficient (result in v)
Definition transforms.h:349
itpp::imag
vec imag(const cvec &data)
Imaginary part of complex values.
Definition elem_math.cpp:180
itpp::real
vec real(const cvec &data)
Real part of complex values.
Definition elem_math.cpp:157
itpp::conj
cvec conj(const cvec &x)
Conjugate of complex value.
Definition elem_math.h:226
itpp::reverse
Vec< T > reverse(const Vec< T > &in)
Reverse the input vector.
Definition matfunc.h:777
itpp
itpp namespace
Definition itmex.h:37
itpp::to_cvec
cvec to_cvec(const Vec< T > &v)
Converts a Vec<T> to cvec.
Definition converters.h:107
itpp::pi
const double pi
Constant Pi.
Definition misc.h:103
itpp::ceil_i
int ceil_i(double x)
The nearest larger integer.
Definition converters.h:339
transforms.h
Fourier, Hadamard, Walsh-Hadamard, and 2D Hadamard transforms - header file.

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