# set terminal pngcairo  transparent enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'zeta.4.png'
set border 895 front lt black linewidth 1.000 dashtype solid
set key fixed right top vertical Right noreverse enhanced autotitle box lt black linewidth 1.000 dashtype solid
set key noinvert samplen 0 spacing 1 width 0 height 0
set key opaque
set view map scale 1
set samples 201, 201
set isosamples 201, 201
set xyplane relative 0
set cbtics  norangelimit 
set cbtics   ("-π" -3.14159, "+π" 3.14159)
set title "{/Times=16 Riemann zeta function}    {/Times:Italic=16 ζ(s) = {∑@_{/*0.5 {k=1}}^{/*.5 ∞}}  {/:Italic=12 k^{ -s}}" 
set trange [ * : * ] noreverse nowriteback
set urange [ * : * ] noreverse nowriteback
set vrange [ * : * ] noreverse nowriteback
set xlabel "Real(s)" 
set xlabel  offset character -1, 0, 0 font "" textcolor lt -1 right norotate
set xrange [ -9.00000 : 9.00000 ] noreverse nowriteback
set x2range [ * : * ] noreverse writeback
set ylabel "Imag(s)" 
set yrange [ -9.00000 : 9.00000 ] noreverse nowriteback
set y2range [ * : * ] noreverse writeback
set zrange [ * : * ] noreverse writeback
set cblabel "Phase Angle" 
set cblabel  offset character -1, 0, 0 font "" textcolor lt -1 rotate
set cbrange [ -3.14159 : 3.14159 ] noreverse writeback
set rrange [ * : * ] noreverse writeback
set pm3d depthorder base
set pm3d interpolate 1,1 flush begin noftriangles noborder corners2color c1
set palette positive nops_allcF maxcolors 0 gamma 1.5 color model HSV 
set palette defined ( 0 0 1 1, 1 1 1 1 )
set colorbox vertical origin screen 0.9, 0.2 size screen 0.05, 0.6 front  noinvert bdefault
NO_ANIMATION = 1
save_encoding = "utf8"
splot arg( zeta(x + I*y) ) with pm3d title "arg(ζ(s))"