i followed the idea from your post.

seems ok  ;D

it is able to compile

but i can't seems to understand the logic of

xs[np]=Hertz;        // i self improvised your 'x' to mean 'Hertz' in my xml
ys[np]=Xmodplot;    // your 'y' to mean 'Xmodplot'
np=np+1;


After clicking on the button on the extreme bottom right , np=np+1; is executed !!

but my variable xs[np] and ys[np] doesn't seems to be doing what i wanted to assign

xs[np]=Hertz;
ys[np]=Xmodplot;


The main thing i wanted is to give users a chance to manually plot out (using EJS) for a particular damping coeff. b

to plot maximum amplitude resonance (Xmodplot) versus frequency of driver (Hertz), so that the experience of experimenting with the system simulation allows a deeper sense of the graphs. (refer to previous post for the picture)

this is a really difficult concept to explain in real life ( i used a water bottle and my hand to act as the driver, to demonstrate resonance ). :D

attached is the xml, thanks for taking time to help me