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optimizing

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Mark Borgerding 2003-12-10 05:20:21 +00:00
parent b737756abb
commit b880c599ef
1 changed files with 13 additions and 7 deletions
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20
fft.py
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@ -68,15 +68,21 @@ def real_fft( f,inv ):
Fp = fft( fp ,0 )
print 'fft output ', Fp
F = []
for k in range(N):
F1k = Fp[k] + Fp[-k].conjugate()
F2k = -j*(Fp[k] - Fp[-k].conjugate())
print 'F2k[%d]=%s' % (k,F2k)
F = [ complex(0,0) ] * ( N+1 )
F[0] = complex( Fp[0].real + Fp[0].imag , 0 )
F.append( ( F1k + e ** ( -j*pi*k/N ) * F2k ) * .5 )
for k in range(1,N/2+1):
tw = e ** ( -j*pi*(.5+float(k)/N ) )
F1k = Fp[k] + Fp[N-k].conjugate()
F2k = Fp[k] - Fp[N-k].conjugate()
F[k] = ( F1k + tw * F2k ) * .5
#F[N-k] = ( F1kp + e ** ( -j*pi*(.5+float(N-k)/N ) ) * F2kp ) * .5
F[N-k] = ( F1k.conjugate() - tw.conjugate() * F2k.conjugate() ) * .5
F.append( complex( Fp[0].real - Fp[0].imag , 0 ) )
F[N] = complex( Fp[0].real - Fp[0].imag , 0 )
return F
def main():