1c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// This file is part of Eigen, a lightweight C++ template library 2c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// for linear algebra. 3c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// 4c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// Copyright (C) 2009 Mark Borgerding mark a borgerding net 5c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// 6c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// This Source Code Form is subject to the terms of the Mozilla 7c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// Public License v. 2.0. If a copy of the MPL was not distributed 8c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// with this file, You can obtain one at http://mozilla.org/MPL/2.0/. 9c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 10c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathnamespace Eigen { 11c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 12c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathnamespace internal { 13c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 14c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // This FFT implementation was derived from kissfft http:sourceforge.net/projects/kissfft 15c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // Copyright 2003-2009 Mark Borgerding 16c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 17c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathtemplate <typename _Scalar> 18c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathstruct kiss_cpx_fft 19c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath{ 20c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath typedef _Scalar Scalar; 21c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath typedef std::complex<Scalar> Complex; 22c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath std::vector<Complex> m_twiddles; 23c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath std::vector<int> m_stageRadix; 24c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath std::vector<int> m_stageRemainder; 25c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath std::vector<Complex> m_scratchBuf; 26c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath bool m_inverse; 27c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 28c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 29c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void make_twiddles(int nfft,bool inverse) 30c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 317faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez using std::acos; 32c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_inverse = inverse; 33c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_twiddles.resize(nfft); 34c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Scalar phinc = (inverse?2:-2)* acos( (Scalar) -1) / nfft; 35c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath for (int i=0;i<nfft;++i) 36c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_twiddles[i] = exp( Complex(0,i*phinc) ); 37c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 38c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 39c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void factorize(int nfft) 40c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 41c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath //start factoring out 4's, then 2's, then 3,5,7,9,... 42c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int n= nfft; 43c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int p=4; 44c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath do { 45c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath while (n % p) { 46c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath switch (p) { 47c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath case 4: p = 2; break; 48c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath case 2: p = 3; break; 49c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath default: p += 2; break; 50c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 51c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if (p*p>n) 52c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath p=n;// impossible to have a factor > sqrt(n) 53c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 54c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath n /= p; 55c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_stageRadix.push_back(p); 56c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_stageRemainder.push_back(n); 57c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if ( p > 5 ) 58c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_scratchBuf.resize(p); // scratchbuf will be needed in bfly_generic 59c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath }while(n>1); 60c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 61c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 62c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath template <typename _Src> 63c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 64c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void work( int stage,Complex * xout, const _Src * xin, size_t fstride,size_t in_stride) 65c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 66c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int p = m_stageRadix[stage]; 67c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int m = m_stageRemainder[stage]; 68c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex * Fout_beg = xout; 69c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex * Fout_end = xout + p*m; 70c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 71c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if (m>1) { 72c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath do{ 73c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // recursive call: 74c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // DFT of size m*p performed by doing 75c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // p instances of smaller DFTs of size m, 76c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // each one takes a decimated version of the input 77c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath work(stage+1, xout , xin, fstride*p,in_stride); 78c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath xin += fstride*in_stride; 79c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath }while( (xout += m) != Fout_end ); 80c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath }else{ 81c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath do{ 82c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath *xout = *xin; 83c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath xin += fstride*in_stride; 84c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath }while(++xout != Fout_end ); 85c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 86c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath xout=Fout_beg; 87c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 88c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // recombine the p smaller DFTs 89c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath switch (p) { 90c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath case 2: bfly2(xout,fstride,m); break; 91c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath case 3: bfly3(xout,fstride,m); break; 92c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath case 4: bfly4(xout,fstride,m); break; 93c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath case 5: bfly5(xout,fstride,m); break; 94c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath default: bfly_generic(xout,fstride,m,p); break; 95c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 96c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 97c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 98c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 99c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void bfly2( Complex * Fout, const size_t fstride, int m) 100c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 101c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath for (int k=0;k<m;++k) { 102c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex t = Fout[m+k] * m_twiddles[k*fstride]; 103c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout[m+k] = Fout[k] - t; 104c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout[k] += t; 105c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 106c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 107c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 108c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 109c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void bfly4( Complex * Fout, const size_t fstride, const size_t m) 110c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 111c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex scratch[6]; 112c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int negative_if_inverse = m_inverse * -2 +1; 113c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath for (size_t k=0;k<m;++k) { 114c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[0] = Fout[k+m] * m_twiddles[k*fstride]; 115c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[1] = Fout[k+2*m] * m_twiddles[k*fstride*2]; 116c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[2] = Fout[k+3*m] * m_twiddles[k*fstride*3]; 117c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[5] = Fout[k] - scratch[1]; 118c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 119c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout[k] += scratch[1]; 120c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[3] = scratch[0] + scratch[2]; 121c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[4] = scratch[0] - scratch[2]; 122c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[4] = Complex( scratch[4].imag()*negative_if_inverse , -scratch[4].real()* negative_if_inverse ); 123c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 124c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout[k+2*m] = Fout[k] - scratch[3]; 125c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout[k] += scratch[3]; 126c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout[k+m] = scratch[5] + scratch[4]; 127c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout[k+3*m] = scratch[5] - scratch[4]; 128c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 129c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 130c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 131c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 132c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void bfly3( Complex * Fout, const size_t fstride, const size_t m) 133c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 134c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath size_t k=m; 135c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath const size_t m2 = 2*m; 136c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex *tw1,*tw2; 137c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex scratch[5]; 138c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex epi3; 139c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath epi3 = m_twiddles[fstride*m]; 140c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 141c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath tw1=tw2=&m_twiddles[0]; 142c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 143c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath do{ 144c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[1]=Fout[m] * *tw1; 145c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[2]=Fout[m2] * *tw2; 146c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 147c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[3]=scratch[1]+scratch[2]; 148c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[0]=scratch[1]-scratch[2]; 149c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath tw1 += fstride; 150c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath tw2 += fstride*2; 151c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout[m] = Complex( Fout->real() - Scalar(.5)*scratch[3].real() , Fout->imag() - Scalar(.5)*scratch[3].imag() ); 152c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[0] *= epi3.imag(); 153c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath *Fout += scratch[3]; 154c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout[m2] = Complex( Fout[m].real() + scratch[0].imag() , Fout[m].imag() - scratch[0].real() ); 155c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout[m] += Complex( -scratch[0].imag(),scratch[0].real() ); 156c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath ++Fout; 157c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath }while(--k); 158c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 159c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 160c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 161c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void bfly5( Complex * Fout, const size_t fstride, const size_t m) 162c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 163c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex *Fout0,*Fout1,*Fout2,*Fout3,*Fout4; 164c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath size_t u; 165c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex scratch[13]; 166c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex * twiddles = &m_twiddles[0]; 167c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex *tw; 168c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex ya,yb; 169c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath ya = twiddles[fstride*m]; 170c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath yb = twiddles[fstride*2*m]; 171c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 172c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout0=Fout; 173c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout1=Fout0+m; 174c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout2=Fout0+2*m; 175c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout3=Fout0+3*m; 176c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout4=Fout0+4*m; 177c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 178c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath tw=twiddles; 179c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath for ( u=0; u<m; ++u ) { 180c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[0] = *Fout0; 181c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 182c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[1] = *Fout1 * tw[u*fstride]; 183c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[2] = *Fout2 * tw[2*u*fstride]; 184c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[3] = *Fout3 * tw[3*u*fstride]; 185c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[4] = *Fout4 * tw[4*u*fstride]; 186c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 187c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[7] = scratch[1] + scratch[4]; 188c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[10] = scratch[1] - scratch[4]; 189c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[8] = scratch[2] + scratch[3]; 190c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[9] = scratch[2] - scratch[3]; 191c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 192c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath *Fout0 += scratch[7]; 193c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath *Fout0 += scratch[8]; 194c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 195c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[5] = scratch[0] + Complex( 196c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath (scratch[7].real()*ya.real() ) + (scratch[8].real() *yb.real() ), 197c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath (scratch[7].imag()*ya.real()) + (scratch[8].imag()*yb.real()) 198c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath ); 199c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 200c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[6] = Complex( 201c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath (scratch[10].imag()*ya.imag()) + (scratch[9].imag()*yb.imag()), 202c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath -(scratch[10].real()*ya.imag()) - (scratch[9].real()*yb.imag()) 203c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath ); 204c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 205c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath *Fout1 = scratch[5] - scratch[6]; 206c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath *Fout4 = scratch[5] + scratch[6]; 207c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 208c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[11] = scratch[0] + 209c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex( 210c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath (scratch[7].real()*yb.real()) + (scratch[8].real()*ya.real()), 211c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath (scratch[7].imag()*yb.real()) + (scratch[8].imag()*ya.real()) 212c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath ); 213c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 214c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratch[12] = Complex( 215c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath -(scratch[10].imag()*yb.imag()) + (scratch[9].imag()*ya.imag()), 216c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath (scratch[10].real()*yb.imag()) - (scratch[9].real()*ya.imag()) 217c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath ); 218c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 219c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath *Fout2=scratch[11]+scratch[12]; 220c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath *Fout3=scratch[11]-scratch[12]; 221c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 222c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath ++Fout0;++Fout1;++Fout2;++Fout3;++Fout4; 223c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 224c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 225c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 226c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath /* perform the butterfly for one stage of a mixed radix FFT */ 227c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 228c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void bfly_generic( 229c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex * Fout, 230c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath const size_t fstride, 231c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int m, 232c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int p 233c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath ) 234c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 235c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int u,k,q1,q; 236c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex * twiddles = &m_twiddles[0]; 237c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex t; 238c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int Norig = static_cast<int>(m_twiddles.size()); 239c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex * scratchbuf = &m_scratchBuf[0]; 240c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 241c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath for ( u=0; u<m; ++u ) { 242c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath k=u; 243c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath for ( q1=0 ; q1<p ; ++q1 ) { 244c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath scratchbuf[q1] = Fout[ k ]; 245c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath k += m; 246c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 247c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 248c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath k=u; 249c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath for ( q1=0 ; q1<p ; ++q1 ) { 250c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int twidx=0; 251c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout[ k ] = scratchbuf[0]; 252c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath for (q=1;q<p;++q ) { 253c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath twidx += static_cast<int>(fstride) * k; 254c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if (twidx>=Norig) twidx-=Norig; 255c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath t=scratchbuf[q] * twiddles[twidx]; 256c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Fout[ k ] += t; 257c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 258c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath k += m; 259c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 260c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 261c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 262c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath}; 263c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 264c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathtemplate <typename _Scalar> 265c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathstruct kissfft_impl 266c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath{ 267c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath typedef _Scalar Scalar; 268c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath typedef std::complex<Scalar> Complex; 269c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 270c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void clear() 271c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 272c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_plans.clear(); 273c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_realTwiddles.clear(); 274c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 275c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 276c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 277c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void fwd( Complex * dst,const Complex *src,int nfft) 278c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 279c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath get_plan(nfft,false).work(0, dst, src, 1,1); 280c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 281c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 282c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 283c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void fwd2( Complex * dst,const Complex *src,int n0,int n1) 284c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 285c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath EIGEN_UNUSED_VARIABLE(dst); 286c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath EIGEN_UNUSED_VARIABLE(src); 287c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath EIGEN_UNUSED_VARIABLE(n0); 288c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath EIGEN_UNUSED_VARIABLE(n1); 289c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 290c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 291c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 292c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void inv2( Complex * dst,const Complex *src,int n0,int n1) 293c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 294c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath EIGEN_UNUSED_VARIABLE(dst); 295c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath EIGEN_UNUSED_VARIABLE(src); 296c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath EIGEN_UNUSED_VARIABLE(n0); 297c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath EIGEN_UNUSED_VARIABLE(n1); 298c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 299c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 300c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // real-to-complex forward FFT 301c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // perform two FFTs of src even and src odd 302c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // then twiddle to recombine them into the half-spectrum format 303c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // then fill in the conjugate symmetric half 304c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 305c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void fwd( Complex * dst,const Scalar * src,int nfft) 306c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 307c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if ( nfft&3 ) { 308c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // use generic mode for odd 309c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_tmpBuf1.resize(nfft); 310c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath get_plan(nfft,false).work(0, &m_tmpBuf1[0], src, 1,1); 311c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath std::copy(m_tmpBuf1.begin(),m_tmpBuf1.begin()+(nfft>>1)+1,dst ); 312c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath }else{ 313c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int ncfft = nfft>>1; 314c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int ncfft2 = nfft>>2; 315c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex * rtw = real_twiddles(ncfft2); 316c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 317c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // use optimized mode for even real 318c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath fwd( dst, reinterpret_cast<const Complex*> (src), ncfft); 319c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex dc = dst[0].real() + dst[0].imag(); 320c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex nyquist = dst[0].real() - dst[0].imag(); 321c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int k; 322c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath for ( k=1;k <= ncfft2 ; ++k ) { 323c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex fpk = dst[k]; 324c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex fpnk = conj(dst[ncfft-k]); 325c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex f1k = fpk + fpnk; 326c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex f2k = fpk - fpnk; 327c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex tw= f2k * rtw[k-1]; 328c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath dst[k] = (f1k + tw) * Scalar(.5); 329c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath dst[ncfft-k] = conj(f1k -tw)*Scalar(.5); 330c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 331c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath dst[0] = dc; 332c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath dst[ncfft] = nyquist; 333c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 334c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 335c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 336c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // inverse complex-to-complex 337c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 338c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void inv(Complex * dst,const Complex *src,int nfft) 339c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 340c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath get_plan(nfft,true).work(0, dst, src, 1,1); 341c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 342c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 343c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // half-complex to scalar 344c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 345c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath void inv( Scalar * dst,const Complex * src,int nfft) 346c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 347c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if (nfft&3) { 348c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_tmpBuf1.resize(nfft); 349c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_tmpBuf2.resize(nfft); 350c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath std::copy(src,src+(nfft>>1)+1,m_tmpBuf1.begin() ); 351c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath for (int k=1;k<(nfft>>1)+1;++k) 352c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_tmpBuf1[nfft-k] = conj(m_tmpBuf1[k]); 353c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inv(&m_tmpBuf2[0],&m_tmpBuf1[0],nfft); 354c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath for (int k=0;k<nfft;++k) 355c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath dst[k] = m_tmpBuf2[k].real(); 356c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath }else{ 357c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // optimized version for multiple of 4 358c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int ncfft = nfft>>1; 359c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int ncfft2 = nfft>>2; 360c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex * rtw = real_twiddles(ncfft2); 361c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_tmpBuf1.resize(ncfft); 362c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_tmpBuf1[0] = Complex( src[0].real() + src[ncfft].real(), src[0].real() - src[ncfft].real() ); 363c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath for (int k = 1; k <= ncfft / 2; ++k) { 364c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex fk = src[k]; 365c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex fnkc = conj(src[ncfft-k]); 366c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex fek = fk + fnkc; 367c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex tmp = fk - fnkc; 368c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex fok = tmp * conj(rtw[k-1]); 369c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_tmpBuf1[k] = fek + fok; 370c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath m_tmpBuf1[ncfft-k] = conj(fek - fok); 371c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 372c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath get_plan(ncfft,true).work(0, reinterpret_cast<Complex*>(dst), &m_tmpBuf1[0], 1,1); 373c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 374c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 375c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 376c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath protected: 377c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath typedef kiss_cpx_fft<Scalar> PlanData; 378c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath typedef std::map<int,PlanData> PlanMap; 379c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 380c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath PlanMap m_plans; 381c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath std::map<int, std::vector<Complex> > m_realTwiddles; 382c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath std::vector<Complex> m_tmpBuf1; 383c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath std::vector<Complex> m_tmpBuf2; 384c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 385c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 386c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int PlanKey(int nfft, bool isinverse) const { return (nfft<<1) | int(isinverse); } 387c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 388c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 389c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath PlanData & get_plan(int nfft, bool inverse) 390c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 391c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath // TODO look for PlanKey(nfft, ! inverse) and conjugate the twiddles 392c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath PlanData & pd = m_plans[ PlanKey(nfft,inverse) ]; 393c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if ( pd.m_twiddles.size() == 0 ) { 394c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath pd.make_twiddles(nfft,inverse); 395c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath pd.factorize(nfft); 396c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 397c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath return pd; 398c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 399c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 400c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath inline 401c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Complex * real_twiddles(int ncfft2) 402c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath { 4037faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez using std::acos; 404c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath std::vector<Complex> & twidref = m_realTwiddles[ncfft2];// creates new if not there 405c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if ( (int)twidref.size() != ncfft2 ) { 406c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath twidref.resize(ncfft2); 407c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath int ncfft= ncfft2<<1; 408c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath Scalar pi = acos( Scalar(-1) ); 409c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath for (int k=1;k<=ncfft2;++k) 410c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath twidref[k-1] = exp( Complex(0,-pi * (Scalar(k) / ncfft + Scalar(.5)) ) ); 411c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 412c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath return &twidref[0]; 413c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath } 414c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath}; 415c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 416c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath} // end namespace internal 417c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 418c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath} // end namespace Eigen 419c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 420c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath/* vim: set filetype=cpp et sw=2 ts=2 ai: */ 421