# set terminal pngcairo  background "#ffffff" enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'circles.3.png'
unset key
set size ratio -1 1,1
set title "Trace of unconstrained optimization with trust-region method" 
set xrange [ -2.50000 : 1.50000 ] noreverse nowriteback
set yrange [ -1.00000 : 2.50000 ] noreverse nowriteback
r = 0.01
types = 6
keyx = -137.0
keyy = -15.0
keyr = 25.0
i = 5
plot 'optimize.dat' with circles lc rgb "blue" fs transparent solid 0.15 noborder,     'optimize.dat' u 1:2 with linespoints lw 2 lc rgb "black"