Restricting the domain of a function plotted on Gnuplot

Question

I am plotting a set of data on Gnuplot, and want to superimpose the function x^2 on the same plot. I can do this like so:

plot \"filename\" usi         


        

Answer 1

The easiest way may be to define a piecewise function using the ternary operator ?:

f(x) = (x > 1 && x < 2) ? x**2 : 1/0
plot "filename" using 1:2, f(x)

Another way is with the replot command:

plot "filename" using 1:2
replot [1:2] x**2