# set terminal pngcairo  transparent enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'ibeta.2.png'
set format x "%.1f" 
set format y "%.2f" 
set key at screen 0.8, 0.7 right top vertical Right reverse enhanced autotitle nobox
set samples 40, 40
set isosamples 40, 40
set style data lines
set xyplane relative 0
set xtics border in scale 1,0.5 mirror norotate  offset character 0, -0.3, 0 autojustify
set title "Incomplete beta integral          {Γ(a+b)/(Γ(a)Γ(b))} {/*2 ∫@_{/*0.5 0}^{/*.5 x}} {/:Italic t^{a-1}(1-t)^{b-1}dt}\n" 
set title  offset character 0, -1, 0 font "" textcolor lt -1 norotate
set xlabel "a" 
set xrange [ 0.00000 : 1.00000 ] noreverse
set ylabel "b" 
set yrange [ 0.00000 : 0.100000 ] noreverse
set zrange [ 0.00000 : 1.00000 ] noreverse
set pm3d interpolate 1,1 flush begin noftriangles border linewidth 0.500 dashtype solid corners2color mean
set pm3d lighting primary 0.5 specular 0.2 spec2 0.5
set pm3d spotlight rgb 0xff0044 rot_x 50 rot_z 90 Phong 4.0
unset colorbox
NO_ANIMATION = 1
save_encoding = "utf8"
z = 0.95
splot ibeta(x,y,z) with pm3d fc "gray75" title sprintf("ibeta(a,b, x=%.2f)",z)