mirror of https://github.com/saitohirga/WSJT-X.git
59 lines
1.5 KiB
Fortran
59 lines
1.5 KiB
Fortran
subroutine afc9(c3,npts,fsample,a,syncpk)
|
|
|
|
complex c3(0:npts-1)
|
|
real a(3),deltaa(3)
|
|
|
|
a(1)=0. !f0
|
|
a(2)=0. !f1
|
|
a(3)=0. !f2
|
|
deltaa(1)=0.4
|
|
deltaa(2)=0.1
|
|
deltaa(3)=0.1
|
|
nterms=3
|
|
|
|
! Start the iteration
|
|
chisqr=0.
|
|
chisqr0=1.e6
|
|
do iter=1,4 !One iteration is enough?
|
|
do j=1,nterms
|
|
chisq1=fchisq(c3,npts,fsample,a)
|
|
fn=0.
|
|
delta=deltaa(j)
|
|
10 a(j)=a(j)+delta
|
|
chisq2=fchisq(c3,npts,fsample,a)
|
|
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=fchisq(c3,npts,fsample,a)
|
|
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.
|
|
! write(*,4000) iter,j,a,-chisq2
|
|
!4000 format(i1,i2,3f10.4,f11.3)
|
|
enddo
|
|
chisqr=fchisq(c3,npts,fsample,a)
|
|
if(chisqr/chisqr0.gt.0.99) exit
|
|
chisqr0=chisqr
|
|
enddo
|
|
|
|
syncpk=-chisqr
|
|
! write(*,4001) a,-chisq2
|
|
!4001 format(3x,3f10.4,f11.3)
|
|
|
|
return
|
|
end subroutine afc9
|