elongation_al(eps_almansi) = 1./sqrt(1. - 2.*eps_almansi)
eps_log(eps_almansi) = log(elongation_al(eps_almansi))

set xlabel "def log 11"
set ylabel "coef poisson : def log 22 / def log 11"
set y2label "variation relative epaisseur (%)"
set y2tics
set grid y2
p   "test_princ.maple" u (eps_log($5)):(-eps_log($6)/eps_log($5)) t 'NU' w p lc 0 pt 4
rep "test_princ.maple" u (eps_log($5)):(100.*($21-0.038)/0.038) axis x1y2 t 'epaisseur' w p lc 1 pt 4
pause -1
