unexpected line in a plot of function defined by parts - gnuplot

Question

I'm trying to plot a piece wise defined function give by,

equation Implemented in gnuplot, like this,

h(x)=0
g(x)=(4/3)*(1-x**3)
plot h(x)*(x<0) + g(x)*(x>0)*(x<1) + h(x)*(x>1)

The problem is that the line that goes from h(x) to g(x) is not a vertical line, is a inclined one. I really need a vertical one.

How to fix it? plot

Answer 1

You mustn't have (mathematically speaking) a connecting line between the noncontinous parts, because that implies that there are actual function values there.

You should do this instead:

plot sample [:0]  h(x) lc 1 title "f(x)", \
            [0:1] g(x) lc 1 notitle, \
            [1:]  h(x) lc 1 notitle