WSJT-X/lib/chkfft3.f90
Joe Taylor c2f8d8ce81 Update the utility program chkfft.
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7153 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2016-10-06 18:30:10 +00:00

178 lines
5.5 KiB
Fortran

program chkfft
! Tests and times one-dimensional FFTs computed by FFTW3
use, intrinsic :: iso_c_binding
use FFTW3
parameter (NMAX=8*1024*1024) !Maximum FFT length
complex a(NMAX),b(NMAX),c(NMAX)
real ar(NMAX),br(NMAX),cr(NMAX)
real mflops
! integer*8 plan1,plan2 !Pointers to stored plans
type(C_PTR) :: plan1,plan2 !Pointers to FFTW plans
character infile*12,arg*8
logical list
common/patience/npatience
equivalence (a,ar),(b,br),(c,cr)
! include 'fftw3.f90' !FFTW definitions
nargs=iargc()
if(nargs.ne.5) then
print*,'Usage: chkfft3 <nfft | infile> nr nw nc np'
print*,' nfft: length of FFT'
print*,' nfft=0: do lengths 2^n, n=2^4 to 2^23'
print*,' infile: name of file with nfft values, one per line'
print*,' nr: 0/1 to not read (or read) wisdom'
print*,' nw: 0/1 to not write (or write) wisdom'
print*,' nc: 0/1 for real or complex data'
print*,' np: 0-4 patience for finding best algorithm'
go to 999
endif
list=.false.
nfft=-1
call getarg(1,infile)
open(10,file=infile,status='old',err=1)
list=.true. !A valid file name was provided
go to 2
1 read(infile,*) nfft !Take first argument to be nfft
2 call getarg(2,arg)
read(arg,*) nr
call getarg(3,arg)
read(arg,*) nw
call getarg(4,arg)
read(arg,*) ncomplex
call getarg(5,arg)
read(arg,*) npatience
if(list) write(*,1000) infile,nr,nw,ncomplex,npatience
1000 format(/'infile: ',a12,' nr:',i2,' nw',i2,' nc:',i2,' np:',i2/)
if(.not.list) write(*,1002) nfft,nr,nw,ncomplex,npatience
1002 format(/'nfft: ',i10,' nr:',i2,' nw',i2,' nc:',i2,' np:',i2/)
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
open(12,file='chkfft.out',status='unknown')
if(nr.ne.0) then
isuccess=fftwf_import_wisdom_from_filename('fftwf_wisdom.dat'//char(0))
if(isuccess.eq.1) then
write(*,1010)
1010 format('Imported FFTW wisdom.')
else
write(*,1012)
1012 format('Failed to import FFTW wisdom.')
go to 999
endif
endif
idum=-1 !Set random seed
ndim=1 !One-dimensional transforms
do i=1,NMAX !Set random data
x=gran()
y=gran()
b(i)=cmplx(x,y) !Generate random data
enddo
iters=1000000
if(list .or. (nfft.gt.0)) then
n1=1
n2=1
if(nfft.eq.-1) n2=999999
write(*,1020)
1020 format(' NFFT Time rms MHz MFlops iters', &
' tplan'/61('-'))
else
n1=4
n2=23
write(*,1030)
1030 format(' n N=2^n Time rms MHz MFlops iters', &
' tplan'/63('-'))
endif
do ii=n1,n2 !Test one or more FFT lengths
if(list) then
read(10,*,end=900) nfft !Read nfft from file
else if(n2.gt.n1) then
nfft=2**ii !Do powers of 2
endif
iformf=1
iformb=1
if(ncomplex.eq.0) then
iformf=0 !Real-to-complex transform
iformb=-1 !Complex-to-real (inverse) transform
endif
if(nfft.gt.NMAX) go to 900
a(1:nfft)=b(1:nfft) !Copy test data into a()
t0=second()
if(ncomplex.ne.0) then
plan1=fftwf_plan_dft_1d(nfft,a,c,-1,nflags)
plan2=fftwf_plan_dft_1d(nfft,a,c,+1,nflags)
else
plan1=fftwf_plan_dft_r2c_1d(nfft,ar,c,nflags)
plan2=fftwf_plan_dft_c2r_1d(nfft,c,ar,nflags)
endif
t2=second()
tplan=t2-t0 !Total planning time for this length
total=0.
do iter=1,iters !Now do many iterations
a(1:nfft)=b(1:nfft) !Copy test data into a()
t0=second()
call fftwf_execute_dft(plan1,a,c)
call fftwf_execute_dft(plan2,c,a)
t1=second()
total=total+t1-t0
if(total.ge.1.0) go to 40 !Cut iterations short if t>1 s
enddo
iter=iters
40 time=0.5*total/iter !Time for one FFT of current length
tplan=0.5*tplan-time !Planning time for one FFT
if(tplan.lt.0) tplan=0.
a(1:nfft)=a(1:nfft)/nfft
! Compute RMS difference between original array and back-transformed array.
sq=0.
if(ncomplex.eq.1) then
do i=1,nfft
sq=sq + real(a(i)-b(i))**2 + imag(a(i)-b(i))**2
enddo
else
do i=1,nfft
sq=sq + (ar(i)-br(i))**2
enddo
endif
rms=sqrt(sq/nfft)
freq=1.e-6*nfft/time
mflops=5.0/(1.e6*time/(nfft*log(float(nfft))/log(2.0)))
if(n2.eq.1 .or. n2.eq.999999) then
write(*,1050) nfft,time,rms,freq,mflops,iter,tplan
write(12,1050) nfft,time,rms,freq,mflops,iter,tplan
1050 format(i8,f11.7,f12.8,f7.2,f8.1,i8,f6.1)
else
write(*,1060) ii,nfft,time,rms,freq,mflops,iter,tplan
write(12,1060) ii,nfft,time,rms,freq,mflops,iter,tplan
1060 format(i2,i8,f11.7,f12.8,f7.2,f8.1,i8,f6.1)
endif
enddo
900 continue
if(nw.eq.1) then
ierr=fftwf_export_wisdom_to_filename('fftwf_wisdom.dat'//char(0))
write(*,1070)
1070 format(/'Exported FFTW wisdom')
endif
call fftwf_destroy_plan(plan1)
call fftwf_destroy_plan(plan2)
999 end program chkfft