# 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 nowriteback
set x2range [ * : * ] noreverse writeback
set ylabel "b" 
set yrange [ 0.00000 : 0.100000 ] noreverse nowriteback
set y2range [ * : * ] noreverse writeback
set zrange [ 0.00000 : 1.00000 ] noreverse writeback
set cbrange [ * : * ] noreverse writeback
set rrange [ * : * ] noreverse writeback
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
set colorbox vertical origin screen 0.9, 0.2 size screen 0.05, 0.6 front  noinvert bdefault
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)