#!rm fft_y.ps
#set term postscript enhanced color
#set output 'fft_y.ps'
name='fft.dat'
#n_fft=256
set multiplot
set origin 0.,0.
unset title
set size 1,0.5
unset logscale
min=1+(n-1)*n_fft/2
set xlabel 'turn'
max=n_fft+(n-1)*n_fft/2
set xrange [min:max]
plot name u ($1+min-1):4 i n:n w l lc 1 t 'position'
set origin 0.,0.5
set title 'vertical'
set logscale y
set xlabel 'fractional tune'
set xrange[0.5:1]
plot name u (1-$1/n_fft/2):($6**2) i n:n w l lc 2 not #, '' u ($2):($6**2) i 5:5 w l  not ,\
# '' u (1-$2):($6**2) i 6:6 w l not , '' u (1-$2):($6**2) i 7:7 w l  not ,\
# '' u (1-$2):($6**2) i 8:8 w l not , '' u (1-$2):($6**2) i 9:9 w l  not ,\
# '' u (1-$2):($6**2) i 10:10 w l  not , '' u (1-$2):($6**2) i 11:11 w l  not