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WIP: cleanup of things related to use of FFTW. More needed!

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This commit is contained in:
Joe Taylor 2024-01-08 18:55:00 -05:00
parent 764fcaadcb
commit 12042f6ae8
6 changed files with 64 additions and 125 deletions
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6
qmap/libqmap/CMakeLists.txt
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@ -10,10 +10,10 @@ set (libq65_FSRCS
decode0.f90
dot.f90
fchisq0.f90
filbig.f90
four2a.f90
fftbig.f90
# four2a.f90
ftninit.f90
ftnquit.f90
# ftnquit.f90
geocentric.f90
getcand2.f90
grid2deg.f90

56
qmap/libqmap/fftbig.f90 Normal file
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@ -0,0 +1,56 @@
subroutine fftbig(dd,nmax)
! Filter and downsample complex data stored in array dd(2,nmax).
! Output is downsampled from 96000 Hz to 1375.125 Hz.
use timer_module, only: timer
parameter (MAXFFT1=5376000,MAXFFT2=77175)
real*4 dd(2,nmax) !Input data
complex ca(MAXFFT1) !FFT of input
complex c4a(MAXFFT2) !Output data
real*8 df
integer*8 plan1
logical first
include 'fftw3.f'
common/cacb/ca
equivalence (rfilt,cfilt)
data first/.true./,npatience/1/
save
if(nmax.lt.0) go to 900
nfft1=MAXFFT1
if(first) then
nflags=FFTW_ESTIMATE
if(npatience.eq.1) nflags=FFTW_ESTIMATE_PATIENT
if(npatience.eq.2) nflags=FFTW_MEASURE
if(npatience.eq.3) nflags=FFTW_PATIENT
if(npatience.eq.4) nflags=FFTW_EXHAUSTIVE
! Plan the big FFT just once
call timer('FFTplan ',0)
call sfftw_plan_dft_1d(plan1,nfft1,ca,ca,FFTW_BACKWARD,nflags)
call timer('FFTplan ',1)
df=96000.d0/nfft1
first=.false.
endif
nz=min(nmax,nfft1)
do i=1,nz
ca(i)=cmplx(dd(1,i),dd(2,i))
enddo
if(nmax.lt.nfft1) then
do i=nmax+1,nfft1
ca(i)=0.
enddo
endif
call timer('FFTbig ',0)
call sfftw_execute(plan1)
call timer('FFTbig ',1)
go to 999
900 call sfftw_destroy_plan(plan1)
999 return
end subroutine fftbig

117
qmap/libqmap/filbig.f90
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@ -1,117 +0,0 @@
subroutine filbig(dd,nmax,f0,newdat,nfsample,c4a,n4)
! Filter and downsample complex data stored in array dd(2,nmax).
! Output is downsampled from 96000 Hz to 1375.125 Hz.
use timer_module, only: timer
parameter (MAXFFT1=5376000,MAXFFT2=77175)
real*4 dd(2,nmax) !Input data
complex ca(MAXFFT1) !FFT of input
complex c4a(MAXFFT2) !Output data
real*8 df
real halfpulse(8) !Impulse response of filter (one sided)
complex cfilt(MAXFFT2) !Filter (complex; imag = 0)
real rfilt(MAXFFT2) !Filter (real)
integer*8 plan1,plan2,plan3,plan4,plan5
logical first
include 'fftw3.f'
common/cacb/ca
equivalence (rfilt,cfilt)
data first/.true./,npatience/1/
data halfpulse/114.97547150,36.57879257,-20.93789101, &
5.89886379,1.59355187,-2.49138308,0.60910773,-0.04248129/
save
if(nmax.lt.0) go to 900
nfft1=MAXFFT1
nfft2=MAXFFT2
if(first) then
nflags=FFTW_ESTIMATE
if(npatience.eq.1) nflags=FFTW_ESTIMATE_PATIENT
if(npatience.eq.2) nflags=FFTW_MEASURE
if(npatience.eq.3) nflags=FFTW_PATIENT
if(npatience.eq.4) nflags=FFTW_EXHAUSTIVE
! Plan the FFTs just once
call timer('FFTplans ',0)
call sfftw_plan_dft_1d(plan1,nfft1,ca,ca,FFTW_BACKWARD,nflags)
call sfftw_plan_dft_1d(plan3,nfft2,c4a,c4a,FFTW_FORWARD,nflags)
call sfftw_plan_dft_1d(plan5,nfft2,cfilt,cfilt,FFTW_BACKWARD,nflags)
call timer('FFTplans ',1)
! Convert impulse response to filter function
do i=1,nfft2
cfilt(i)=0.
enddo
fac=0.00625/nfft1
cfilt(1)=fac*halfpulse(1)
do i=2,8
cfilt(i)=fac*halfpulse(i)
cfilt(nfft2+2-i)=fac*halfpulse(i)
enddo
call sfftw_execute(plan5)
base=cfilt(nfft2/2+1)
do i=1,nfft2
rfilt(i)=real(cfilt(i))-base
enddo
df=96000.d0/nfft1
first=.false.
endif
! When new data comes along, we need to compute a new "big FFT"
! If we just have a new f0, continue with the existing ca.
if(newdat.ne.0 .or. sum(abs(ca)).eq.0.0) then !### Test on ca should be unnecessary?
nz=min(nmax,nfft1)
do i=1,nz
ca(i)=cmplx(dd(1,i),dd(2,i))
enddo
if(nmax.lt.nfft1) then
do i=nmax+1,nfft1
ca(i)=0.
enddo
endif
call timer('FFTbig ',0)
call sfftw_execute(plan1)
call timer('FFTbig ',1)
!### newdat=0
endif
! NB: f0 is the frequency at which we want our filter centered.
! i0 is the bin number in ca closest to f0.
i0=nint(f0/df) + 1
nh=nfft2/2
do i=1,nh !Copy data into c4a
j=i0+i-1 !and apply the filter function
if(j.ge.1 .and. j.le.nfft1) then
c4a(i)=rfilt(i)*ca(j)
else
c4a(i)=0.
endif
enddo
do i=nh+1,nfft2
j=i0+i-1-nfft2
if(j.lt.1) j=j+nfft1
c4a(i)=rfilt(i)*ca(j)
enddo
! Do the short reverse transform, to go back to time domain.
call timer('FFTsmall',0)
call sfftw_execute(plan3)
call timer('FFTsmall',1)
n4=min(nmax/64,nfft2)
go to 999
900 call sfftw_destroy_plan(plan1)
call sfftw_destroy_plan(plan2)
call sfftw_destroy_plan(plan3)
call sfftw_destroy_plan(plan4)
call sfftw_destroy_plan(plan5)
999 return
end subroutine filbig

2
qmap/libqmap/ftnquit.f90
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@ -2,7 +2,7 @@ subroutine ftnquit
! Destroy the FFTW plans
call four2a(a,-1,1,1,1)
call filbig(id,-1,f0,newdat,nfsample,c4a,n4)
call fftbig(id,-1)
return
end subroutine ftnquit

2
qmap/libqmap/q65b.f90
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@ -54,7 +54,7 @@ subroutine q65b(nutc,nqd,fcenter,nfcal,nfsample,ikhz,mousedf,ntol, &
cx=fac*cx
! Here cx is frequency-domain data around the selected
! QSO frequency, taken from the full-length FFT computed in filbig().
! QSO frequency, taken from the full-length FFT computed in fftbig().
! Values for fsample, nfft1, nfft2, df, and the downsampled data rate
! are as follows:

6
qmap/libqmap/qmapa.f90
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@ -57,9 +57,9 @@ subroutine qmapa(dd,ss,savg,newdat,nutc,fcenter,ntol,nfa,nfb, &
bClickDecode=(nagain.eq.1)
nagain2=0
call timer('filbig ',0)
call filbig(dd,NSMAX,f0,newdat,nfsample,cx,n5) !Do the full-length FFT
call timer('filbig ',1)
call timer('fftbig ',0)
call fftbig(dd,NSMAX) !Do the full-length FFT
call timer('fftbig ',1)
do icand=1,ncand !Attempt to decode each candidate
f0=cand(icand)%f