Re: [Gnuplot-info] fitting function

[Hans-Bernhard B. <HBB...@t-...>]

Sabari wrote:

> What is the difference between  "using 1:2:3 and using 1:2:3:(1)" for 2d fit

Primarily that one of them is _not_ a 2D fit.  Which of those that is 
depends on what exactly you mean by "2D" fit.

> fit f(x,y) "nor.dat" using 1:2:3 via a,b,c

This won't work.  A fit with 2 independent variables needs four using 
specifications: x, y, z and delta_z.  If your data file lacks a delta_z 
column, you have to invent one, like that:

> fit f(x,y) "nor.dat" using 1:2:3:(1)  via a,b,c

And since all of this is described right on the first page of "help 
fit", I really wonder how you managed to miss this.