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57 lines
1.3 KiB
Fortran
57 lines
1.3 KiB
Fortran
subroutine fftbig(dd,nmax)
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! Filter and downsample complex data stored in array dd(2,nmax).
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! Output is downsampled from 96000 Hz to 1375.125 Hz.
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use timer_module, only: timer
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parameter (MAXFFT1=5376000,MAXFFT2=77175)
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real*4 dd(2,nmax) !Input data
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complex ca(MAXFFT1) !FFT of input
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complex c4a(MAXFFT2) !Output data
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real*8 df
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integer*8 plan1
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logical first
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include 'fftw3.f'
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common/cacb/ca
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equivalence (rfilt,cfilt)
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data first/.true./,npatience/1/
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save
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if(nmax.lt.0) go to 900
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nfft1=MAXFFT1
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if(first) then
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nflags=FFTW_ESTIMATE
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if(npatience.eq.1) nflags=FFTW_ESTIMATE_PATIENT
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if(npatience.eq.2) nflags=FFTW_MEASURE
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if(npatience.eq.3) nflags=FFTW_PATIENT
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if(npatience.eq.4) nflags=FFTW_EXHAUSTIVE
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! Plan the big FFT just once
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call timer('FFTplan ',0)
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call sfftw_plan_dft_1d(plan1,nfft1,ca,ca,FFTW_BACKWARD,nflags)
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call timer('FFTplan ',1)
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df=96000.d0/nfft1
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first=.false.
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endif
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nz=min(nmax,nfft1)
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do i=1,nz
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ca(i)=cmplx(dd(1,i),dd(2,i))
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enddo
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if(nmax.lt.nfft1) then
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do i=nmax+1,nfft1
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ca(i)=0.
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enddo
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endif
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call timer('FFTbig ',0)
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call sfftw_execute(plan1)
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call timer('FFTbig ',1)
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go to 999
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900 call sfftw_destroy_plan(plan1)
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999 return
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end subroutine fftbig
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