Re: [Gnuplot-info] Problem with fitting

[<br...@ph...>]

Edward Holness wrote:
> This works perfectly, what doesn't work is trying to fit a straight line 
> too it for which I am trying:
> f(x) = a*x + b
> a = 1e-23
> b = 0
> fit f(x) 'data.txt' using 1:2:3:4 via a, b

This has two errors. First, "using 1:2:3:4" in "fit" means you're doing
a 3D fit (f(x,y) fitted to [x,y,z]). Fit, by design, can't have x error
bars.  Make that "using 1:2:4".

Second, start-up values for parameters can't be zero.  It even says so 
somewhere below "help fit", IIRC.