# set terminal svg size 600,400 dynamic enhanced fname 'arial'  fsize 10 mousing name "cerf_3" butt solid 
# set output 'cerf.3.svg'
unset key
set view map
set samples 200, 200
set isosamples 75, 75
set contour base
set cntrlabel onecolor format '%8.3g' font '' start 5 interval 20
set cntrparam levels discrete 0.1,0.2 ,0.5 ,1 ,2 ,5 ,10 ,20 ,50 ,100 ,200 ,500 
set size ratio 1 1,1
set xtics border in scale 0,0 mirror norotate  offset character 0, 0, 0 autojustify
set ytics border in scale 0,0 mirror norotate  offset character 0, 0, 0 autojustify
set ztics border in scale 0,0 nomirror norotate  offset character 0, 0, 0 autojustify
set cbtics border in scale 0,0 mirror norotate  offset character 0, 0, 0 autojustify
set cbtics  norangelimit
set cbtics   ("0" -3.14159, "2π" 3.14159)
set rtics axis in scale 0,0 nomirror norotate  offset character 0, 0, 0 autojustify
set title "Complex error function cerf( x + iy )" 
set xrange [ -3.00000 : 3.00000 ] noreverse nowriteback
set yrange [ -3.00000 : 3.00000 ] noreverse nowriteback
set cblabel "Phase Angle" 
set cblabel  offset character -2, 0, 0 font "" textcolor lt -1 rotate by -270
set cbrange [ -3.14159 : 3.14159 ] noreverse nowriteback
set bmargin at screen 0.1
set palette positive nops_allcF maxcolors 0 gamma 1.5 color model HSV 
set palette defined ( 0 0 1 1, 1 1 1 1 )
Hue(x,y) = (pi + atan2(-y,-x)) / (2*pi)
phase(x,y) = hsv2rgb( Hue(x,y), sqrt(x**2+y**2), 1. )
rp(x,y) = real(f(x,y))
f(x,y) = cerf(x+y*{0,1})
ip(x,y) = imag(f(x,y))
color(x,y) = hsv2rgb( Hue( rp(x,y), ip(x,y) ), abs(f(x,y)), 1. )
GPFUN_Hue = "Hue(x,y) = (pi + atan2(-y,-x)) / (2*pi)"
GPFUN_phase = "phase(x,y) = hsv2rgb( Hue(x,y), sqrt(x**2+y**2), 1. )"
GPFUN_rp = "rp(x,y) = real(f(x,y))"
GPFUN_ip = "ip(x,y) = imag(f(x,y))"
GPFUN_color = "color(x,y) = hsv2rgb( Hue( rp(x,y), ip(x,y) ), abs(f(x,y)), 1. )"
GPFUN_f = "f(x,y) = cerf(x+y*{0,1})"
x = 0.0
splot '++' using 1:2:(color($1,$2)) with pm3d lc rgb variable nocontour,       '++' using 1:2:(abs(cerf($1+$2*{0,1}))) with lines nosurf lt -1