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Removed macro-like looking private methods of kissfft class.

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All uses of these function were replaced by their implementation (which is mostly easier to read than the functions themselves).
This commit is contained in:
Ralph Tandetzky 2016-04-21 12:11:45 +02:00
parent f78c115f92
commit b10fb43644
1 changed files with 33 additions and 50 deletions
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83
kissfft.hh
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@ -14,7 +14,7 @@ struct traits
std::size_t nfft,
bool inverse )
{
T_scalar phinc = (inverse?2:-2)* acos( (T_scalar) -1) / nfft;
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) );
}
@ -116,20 +116,10 @@ class kissfft
}
}
// these were #define macros in the original kiss_fft
static void C_ADD( cpx_type & c,const cpx_type & a,const cpx_type & b) { c=a+b;}
static void C_MUL( cpx_type & c,const cpx_type & a,const cpx_type & b) { c=a*b;}
static void C_SUB( cpx_type & c,const cpx_type & a,const cpx_type & b) { c=a-b;}
static void C_ADDTO( cpx_type & c,const cpx_type & a) { c+=a;}
static void C_FIXDIV( cpx_type & ,int ) {} // NO-OP for float types
static scalar_type S_MUL( const scalar_type & a,const scalar_type & b) { return a*b;}
static scalar_type HALF_OF( const scalar_type & a) { return a*.5;}
static void C_MULBYSCALAR(cpx_type & c,const scalar_type & a) {c*=a;}
void kf_bfly2( cpx_type * Fout, const size_t fstride, std::size_t m) const
{
for (std::size_t k=0;k<m;++k) {
cpx_type t = Fout[m+k] * _twiddles[k*fstride];
const cpx_type t = Fout[m+k] * _twiddles[k*fstride];
Fout[m+k] = Fout[k] - t;
Fout[k] += t;
}
@ -169,25 +159,22 @@ class kissfft
tw1=tw2=&_twiddles[0];
do{
C_FIXDIV(*Fout,3); C_FIXDIV(Fout[m],3); C_FIXDIV(Fout[m2],3);
scratch[1] = Fout[m] * *tw1;
scratch[2] = Fout[m2] * *tw2;
C_MUL(scratch[1],Fout[m] , *tw1);
C_MUL(scratch[2],Fout[m2] , *tw2);
C_ADD(scratch[3],scratch[1],scratch[2]);
C_SUB(scratch[0],scratch[1],scratch[2]);
scratch[3] = scratch[1] + scratch[2];
scratch[0] = scratch[1] - scratch[2];
tw1 += fstride;
tw2 += fstride*2;
Fout[m] = cpx_type( Fout->real() - HALF_OF(scratch[3].real() ) , Fout->imag() - HALF_OF(scratch[3].imag() ) );
Fout[m] = Fout[0] - scratch[3]*scalar_type(0.5);
scratch[0] *= epi3.imag();
C_MULBYSCALAR( scratch[0] , epi3.imag() );
C_ADDTO(*Fout,scratch[3]);
Fout[0] += scratch[3];
Fout[m2] = cpx_type( Fout[m].real() + scratch[0].imag() , Fout[m].imag() - scratch[0].real() );
C_ADDTO( Fout[m] , cpx_type( -scratch[0].imag(),scratch[0].real() ) );
Fout[m] += cpx_type( -scratch[0].imag(),scratch[0].real() );
++Fout;
}while(--k);
}
@ -206,48 +193,47 @@ class kissfft
Fout4=Fout0+4*m;
for ( std::size_t u=0; u<m; ++u ) {
C_FIXDIV( *Fout0,5); C_FIXDIV( *Fout1,5); C_FIXDIV( *Fout2,5); C_FIXDIV( *Fout3,5); C_FIXDIV( *Fout4,5);
scratch[0] = *Fout0;
C_MUL(scratch[1] ,*Fout1, _twiddles[u*fstride]);
C_MUL(scratch[2] ,*Fout2, _twiddles[2*u*fstride]);
C_MUL(scratch[3] ,*Fout3, _twiddles[3*u*fstride]);
C_MUL(scratch[4] ,*Fout4, _twiddles[4*u*fstride]);
scratch[1] = *Fout1 * _twiddles[ u*fstride];
scratch[2] = *Fout2 * _twiddles[2*u*fstride];
scratch[3] = *Fout3 * _twiddles[3*u*fstride];
scratch[4] = *Fout4 * _twiddles[4*u*fstride];
C_ADD( scratch[7],scratch[1],scratch[4]);
C_SUB( scratch[10],scratch[1],scratch[4]);
C_ADD( scratch[8],scratch[2],scratch[3]);
C_SUB( scratch[9],scratch[2],scratch[3]);
scratch[7] = scratch[1] + scratch[4];
scratch[10]= scratch[1] - scratch[4];
scratch[8] = scratch[2] + scratch[3];
scratch[9] = scratch[2] - scratch[3];
C_ADDTO( *Fout0, scratch[7]);
C_ADDTO( *Fout0, scratch[8]);
*Fout0 += scratch[7];
*Fout0 += scratch[8];
scratch[5] = scratch[0] + cpx_type(
S_MUL(scratch[7].real(),ya.real()) + S_MUL(scratch[8].real(),yb.real() ),
S_MUL(scratch[7].imag(),ya.real()) + S_MUL(scratch[8].imag(),yb.real())
scratch[7].real()*ya.real() + scratch[8].real()*yb.real(),
scratch[7].imag()*ya.real() + scratch[8].imag()*yb.real()
);
scratch[6] = cpx_type(
S_MUL(scratch[10].imag(),ya.imag()) + S_MUL(scratch[9].imag(),yb.imag()),
-S_MUL(scratch[10].real(),ya.imag()) - S_MUL(scratch[9].real(),yb.imag())
scratch[10].imag()*ya.imag() + scratch[9].imag()*yb.imag(),
-scratch[10].real()*ya.imag() - scratch[9].real()*yb.imag()
);
C_SUB(*Fout1,scratch[5],scratch[6]);
C_ADD(*Fout4,scratch[5],scratch[6]);
*Fout1 = scratch[5] - scratch[6];
*Fout4 = scratch[5] + scratch[6];
scratch[11] = scratch[0] +
cpx_type(
S_MUL(scratch[7].real(),yb.real()) + S_MUL(scratch[8].real(),ya.real()),
S_MUL(scratch[7].imag(),yb.real()) + S_MUL(scratch[8].imag(),ya.real())
scratch[7].real()*yb.real() + scratch[8].real()*ya.real(),
scratch[7].imag()*yb.real() + scratch[8].imag()*ya.real()
);
scratch[12] = cpx_type(
-S_MUL(scratch[10].imag(),yb.imag()) + S_MUL(scratch[9].imag(),ya.imag()),
S_MUL(scratch[10].real(),yb.imag()) - S_MUL(scratch[9].real(),ya.imag())
-scratch[10].imag()*yb.imag() + scratch[9].imag()*ya.imag(),
scratch[10].real()*yb.imag() - scratch[9].real()*ya.imag()
);
C_ADD(*Fout2,scratch[11],scratch[12]);
C_SUB(*Fout3,scratch[11],scratch[12]);
*Fout2 = scratch[11] + scratch[12];
*Fout3 = scratch[11] - scratch[12];
++Fout0;
++Fout1;
@ -272,7 +258,6 @@ class kissfft
std::size_t k = u;
for ( std::size_t q1=0 ; q1<p ; ++q1 ) {
scratchbuf[q1] = Fout[ k ];
C_FIXDIV(scratchbuf[q1],p);
k += m;
}
@ -284,9 +269,7 @@ class kissfft
twidx += fstride * k;
if (twidx>=_nfft)
twidx-=_nfft;
cpx_type t;
C_MUL(t,scratchbuf[q] , twiddles[twidx] );
C_ADDTO( Fout[ k ] ,t);
Fout[ k ] += scratchbuf[q] * twiddles[twidx];
}
k += m;
}