real function fchisq0(y,npts,a)
real y(npts),a(4)
! rewind 51
chisq = 0.
do i=1,npts
x=i
z=(x-a(3))/(0.5*a(4))
yfit=a(1)
if(abs(z).lt.3.0) then
d=1.0 + z*z
yfit=a(1) + a(2) * (1.0/d - 0.1)
endif
chisq=chisq + (y(i) - yfit)**2
! write(51,3001) i,y(i),yfit,y(i)-yfit
!3001 format(i5,3f10.4)
enddo
fchisq0=chisq
return
end function fchisq0
