subroutine find_peaks(fft,tune)
     use bmad
     implicit none
     real(rp), dimension(:),intent(in) :: fft
     real(rp), dimension(:), intent(out) :: tune
     real(rp), allocatable::ra(:)
     real(rp) d,b,a,c
      integer n,i,j,imx(10)
 
     n=size(fft)
     allocate(ra(n))
     ra(:) = abs(fft(:))

     do i = 1,10
      imx(i) = maxloc(ra(5:n-5),1) + 4 
      d= ra(imx(i))
      b=ra(imx(i)+1)
      if(d /= 0. .or. b /= 0.)then
       c=cos(twopi/n)
       A= (-(d+b*c)*(d-b)+b*sqrt(c*c*(d+b)*(d+b)-2*d*b*(2*c*c-c-1)))/(d*d+b*b+2*d*b*c)
      endif
!      int_tune(i) = imx(i)/float(n)
      tune(i)= imx(i)/float(n)+(1/twopi)*asin(A*sin(twopi/float(n)))
      do j = max(1,imx(i)-20),min(n,imx(i)+20)
       ra(j)=0.
      end do
     end do
   return
   end