mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-26 22:28:41 -05:00
103 lines
2.2 KiB
Fortran
103 lines
2.2 KiB
Fortran
|
subroutine lorentzian(y,npts,a)
|
||
|
|
|
||
|
|
! Input: y(npts); assume x(i)=i, i=1,npts
|
||
|
|
! Output: a(5)
|
||
|
|
! a(1) = baseline
|
||
|
|
! a(2) = amplitude
|
||
|
|
! a(3) = x0
|
||
|
|
! a(4) = width
|
||
|
|
! a(5) = chisqr
|
||
|
|
|
||
|
|
real y(npts)
|
||
|
|
real a(5)
|
||
|
|
real deltaa(4)
|
||
|
|
|
||
|
|
a=0.
|
||
|
|
df=12000.0/8192.0 !df = 1.465 Hz
|
||
|
|
width=0.
|
||
|
|
ipk=0
|
||
|
|
ymax=-1.e30
|
||
|
|
do i=1,npts
|
||
|
|
if(y(i).gt.ymax) then
|
||
|
|
ymax=y(i)
|
||
|
|
ipk=i
|
||
|
|
endif
|
||
|
|
! write(50,3001) i,i*df,y(i)
|
||
|
|
!3001 format(i6,2f12.3)
|
||
|
|
enddo
|
||
|
|
! base=(sum(y(ipk-149:ipk-50)) + sum(y(ipk+51:ipk+150)))/200.0
|
||
|
|
base=(sum(y(1:20)) + sum(y(npts-19:npts)))/40.0
|
||
|
|
stest=ymax - 0.5*(ymax-base)
|
||
|
|
ssum=y(ipk)
|
||
|
|
do i=1,50
|
||
|
|
if(ipk+i.gt.npts) exit
|
||
|
|
if(y(ipk+i).lt.stest) exit
|
||
|
|
ssum=ssum + y(ipk+i)
|
||
|
|
enddo
|
||
|
|
do i=1,50
|
||
|
|
if(ipk-i.lt.1) exit
|
||
|
|
if(y(ipk-i).lt.stest) exit
|
||
|
|
ssum=ssum + y(ipk-i)
|
||
|
|
enddo
|
||
|
|
ww=ssum/y(ipk)
|
||
|
|
width=2
|
||
|
|
t=ww*ww - 5.67
|
||
|
|
if(t.gt.0.0) width=sqrt(t)
|
||
|
|
a(1)=base
|
||
|
|
a(2)=ymax-base
|
||
|
|
a(3)=ipk
|
||
|
|
a(4)=width
|
||
|
|
|
||
|
|
! Now find Lorentzian parameters
|
||
|
|
|
||
|
|
deltaa(1)=0.1
|
||
|
|
deltaa(2)=0.1
|
||
|
|
deltaa(3)=1.0
|
||
|
|
deltaa(4)=1.0
|
||
|
|
nterms=4
|
||
|
|
|
||
|
|
! Start the iteration
|
||
|
|
chisqr=0.
|
||
|
|
chisqr0=1.e6
|
||
|
|
do iter=1,5
|
||
|
|
do j=1,nterms
|
||
|
|
chisq1=fchisq0(y,npts,a)
|
||
|
|
fn=0.
|
||
|
|
delta=deltaa(j)
|
||
|
|
10 a(j)=a(j)+delta
|
||
|
|
chisq2=fchisq0(y,npts,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=fchisq0(y,npts,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,i2,4f10.4,f11.3)
|
||
|
|
enddo
|
||
|
|
chisqr=fchisq0(y,npts,a)
|
||
|
|
! write(*,4000) 0,0,a,chisqr
|
||
|
|
if(chisqr/chisqr0.gt.0.99) exit
|
||
|
|
chisqr0=chisqr
|
||
|
|
enddo
|
||
|
|
a(5)=chisqr
|
||
|
|
|
||
|
|
return
|
||
|
|
end subroutine lorentzian
|
||
|
|
|