file = 'vis_45_L300_R300_P0_ScanRhwp_RightHWP_3_inttime_800_20140111_1830'
#file = 'vis_45lockedL300R300_LeftHWP_2_inttime_800_20140110_0151'
#inttime=800
tit=""
#set x2label "Left HWP position" 
unset x2label
#set title "Visibility in the \261 45\260 Basis"
unset title
set terminal postscript color enhanced "Helvetica" 8 size 9cm,6.77cm
set output file . '.eps'


#express the offset o interms of the visibility v for a model which fits better
f(t) =  a*(sin(c*(t-p))**2) + (a/2)*((1-v)/v)

v=0.990748
a=2200
c=2*pi/180.0 # FIXED
p=-90*-300/600.0+67.5
set border 15
set xtics format "%g"
set xtics ("-67.5" -67.5,"-45" -45, "-22.5" -22.5, "0" 0, "22.5" 22.5, "45" 45, "67.5" 67.5)
set xtics nomirror
#set x2tics 300
#set x2range [-1000:1000] 
unset x2tics
unset x2range
unset ytics
set xrange[-67.5:67.5]
set yrange [0:a+a/20]
FIT_LIMIT = 1e-15
set fit errorvariables
fit [-67.5:0] f(x) file u (($2/1200)*90):($9):(sqrt($9)) via v,a,p

set ylabel "Pairs"

set xlabel "HWP angle (\260)"

#visibility error
#o=(a/2)*((1-v)/v)
#error=2*sqrt( ((a_err*a)**2 + (o_err*o)**2) / ((a+o)**4) )
#vis= (a-o)/(a+o)
#print "visibility is: ",vis
#print "Error is: ", error

unset label 1
set encoding iso_8859_1 
set label 1 sprintf("Visibility from fit = \n %2.1f \261 %2.1f %",v*100,v_err*100) at -40,500 tc rgb "red"
set style line 4 default
set style line 4  ps 0.1 lt 1 lc 3 pt 6 lw 1
plot f(x) lt 1 lw 2 title "" , file u (($2/1200)*90):($9):(sqrt($9))   ls 4 w yerrorbars title tit

#set terminal windows
#plot file u 2:($9) w p lt 1 lw 2 axes x2y1 title "", f(x) lt 1 lw 2 title "" , file u (($2/600)*90):($9)  w lt 1 lw 2 title tit