mirror/kissfft
1
0
Fork 0
mirror of https://github.com/mborgerding/kissfft.git synced 2025-05-27 21:20:27 -04:00
Code Issues Packages Projects Releases Wiki Activity

Removed the needless use of a traits class.

Browse Source
This commit is contained in:
Ralph Tandetzky 2016-04-21 13:20:29 +02:00
parent b10fb43644
commit 0395af753e
1 changed files with 27 additions and 53 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

80
kissfft.hh
View File

@ -3,71 +3,45 @@
#include <complex>
#include <vector>
namespace kissfft_utils {
template <typename T_scalar>
struct traits
{
typedef T_scalar scalar_type;
typedef std::complex<scalar_type> cpx_type;
static void fill_twiddles( cpx_type * dst,
std::size_t nfft,
bool inverse )
{
const T_scalar phinc = (inverse?2:-2)* acos( (T_scalar) -1) / nfft;
for (std::size_t i=0;i<nfft;++i)
dst[i] = std::exp( cpx_type(0,i*phinc) );
}
static void prepare(
std::vector< cpx_type > & _twiddles,
std::size_t nfft,
bool inverse,
std::vector<std::size_t> & stageRadix,
std::vector<std::size_t> & stageRemainder )
{
_twiddles.resize(nfft);
fill_twiddles( &_twiddles[0],nfft,inverse);
//factorize
//start factoring out 4's, then 2's, then 3,5,7,9,...
std::size_t n= nfft;
std::size_t p=4;
do {
while (n % p) {
switch (p) {
case 4: p = 2; break;
case 2: p = 3; break;
default: p += 2; break;
}
if (p*p>n)
p = n;// no more factors
}
n /= p;
stageRadix.push_back(p);
stageRemainder.push_back(n);
}while(n>1);
}
};
}
template <typename T_Scalar,
typename T_traits=kissfft_utils::traits<T_Scalar>
typename T_Complex=std::complex<T_Scalar>
>
class kissfft
{
public:
typedef T_traits traits_type;
typedef typename traits_type::scalar_type scalar_type;
typedef typename traits_type::cpx_type cpx_type;
typedef T_Scalar scalar_type;
typedef T_Complex cpx_type;
kissfft( std::size_t nfft,
bool inverse )
:_nfft(nfft)
,_inverse(inverse)
{
T_traits::prepare(_twiddles, _nfft,_inverse ,_stageRadix, _stageRemainder);
// fill twiddle factors
_twiddles.resize(_nfft);
const scalar_type phinc = (_inverse?2:-2)* acos( (scalar_type) -1) / _nfft;
for (std::size_t i=0;i<_nfft;++i)
_twiddles[i] = std::exp( cpx_type(0,i*phinc) );
//factorize
//start factoring out 4's, then 2's, then 3,5,7,9,...
std::size_t n= _nfft;
std::size_t p=4;
do {
while (n % p) {
switch (p) {
case 4: p = 2; break;
case 2: p = 3; break;
default: p += 2; break;
}
if (p*p>n)
p = n;// no more factors
}
n /= p;
_stageRadix.push_back(p);
_stageRemainder.push_back(n);
}while(n>1);
}
void transform( const cpx_type * src,