mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-16 17:11:53 -05:00
56e3638bc5
displayed DT values appear to be to low by 0.2 s -- they range from -2.2 s to +4.8 s, according to files generated by jt65sim. git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6179 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
59 lines
1.5 KiB
Fortran
59 lines
1.5 KiB
Fortran
subroutine afc65b(cx,npts,fsample,nflip,a,ccfbest,dtbest)
|
|
|
|
! Find delta f, f1, f2 ==> a(1:3)
|
|
|
|
complex cx(npts)
|
|
real a(5),deltaa(5)
|
|
|
|
a(1)=0.
|
|
a(2)=0.
|
|
a(3)=0.
|
|
a(4)=0.
|
|
deltaa(1)=2.0
|
|
deltaa(2)=2.0
|
|
deltaa(3)=1.0
|
|
nterms=2 !Maybe 2 is enough?
|
|
|
|
! Start the iteration
|
|
chisqr=0.
|
|
chisqr0=1.e6
|
|
do iter=1,3 !One iteration is enough?
|
|
do j=1,nterms
|
|
chisq1=fchisq65(cx,npts,fsample,nflip,a,ccfmax,dtmax)
|
|
fn=0.
|
|
delta=deltaa(j)
|
|
10 a(j)=a(j)+delta
|
|
chisq2=fchisq65(cx,npts,fsample,nflip,a,ccfmax,dtmax)
|
|
if(chisq2.eq.chisq1) go to 10
|
|
if(chisq2.gt.chisq1) then
|
|
delta=-delta !Reverse direction
|
|
a(j)=a(j)+delta
|
|
tmp=chisq1
|
|
chisq1=chisq2
|
|
chisq2=tmp
|
|
endif
|
|
20 fn=fn+1.0
|
|
a(j)=a(j)+delta
|
|
chisq3=fchisq65(cx,npts,fsample,nflip,a,ccfmax,dtmax)
|
|
if(chisq3.lt.chisq2) then
|
|
chisq1=chisq2
|
|
chisq2=chisq3
|
|
go to 20
|
|
endif
|
|
|
|
! Find minimum of parabola defined by last three points
|
|
delta=delta*(1./(1.+(chisq1-chisq2)/(chisq3-chisq2))+0.5)
|
|
a(j)=a(j)-delta
|
|
deltaa(j)=deltaa(j)*fn/3.
|
|
enddo
|
|
chisqr=fchisq65(cx,npts,fsample,nflip,a,ccfmax,dtmax)
|
|
if(chisqr/chisqr0.gt.0.9999) go to 30
|
|
chisqr0=chisqr
|
|
enddo
|
|
|
|
30 ccfbest=ccfmax * (1378.125/fsample)**2
|
|
dtbest=dtmax
|
|
|
|
return
|
|
end subroutine afc65b
|