|
From: GOO C. <goo...@gm...> - 2014-08-25 10:16:36
|
Thanks, that did the trick. though it would be something like this. Chris On 2014/08/25 11:57 AM, Marek W. Gutowski wrote: > > From: GOO Creations > > To: gnu...@li... > > Cc: > > Date: 2014/8/25, Mon 16:07 > > Subject: [Gnuplot-info] Step function not starting at absolute 0 > > > > Hi all, > > > > I'm trying to create a simple step function. I have this weird > problem that > > the x-values of my function do not start at absolute 0, therefore > creating a > > skew function. Here is my code: > > > > /set xzeroaxis lc "black"// > > //set yzeroaxis lc "black"// > > //set terminal pdf// > > //set output "step.pdf"// > > //f(x)= x <= 0 ? -1 : 1// > > //plot f(x) lw 2 lc "black"// > > / > > > > > > I've also attached the output PDF. As you can see the middle part of > the > > function is not parrallel with the y-axis. Does anyone know what I'm > missing > > > > Chris > > This is not strange because the sampling points in x axis is a finite > number. > (default 100). > Increasing sample number like "set sample 1000", the appearance will > be better but > that is the results mere approximation will be better. > > Tatsuro > > > > Here are my "two cents": > > 1. Original function has a jump at x=0. Formally, nothing like vertical > line should be drawn at x=0. The reason for "incorrect" drawing > has been already pointed by Tatsuro. > > 2. Correct solution is to define TWO functions: > f(x) = x<=0.0?-1.0:1/0 > g(x)=x>0.0?1.0:1/0 > > and plot them both, say > plot [*:*][-1.1:1.1] f(x) lw 2 lc "black", g(x) lw 2 lc "black" > > Now you have a plot which is indeed correct. > > Cheers, > Marek Gutowski |