Re: [Gnuplot-info] Plot from data file: read multiple rows at the same time

[Lars H. <la...@ho...>]

On Wednesday, November 15th, 2006 at 17:14 h Marco Calviani 
wrote:

> i would like to plot on the y axis of the graph
> "function/(energy-(energy-1))" where energy-1 is the 
> "energy" column before the active one. For example for
> the table above that would be 30/(3-2).
> Is this possible with gnuplot?

As I see it there is no sophisticated way using the interna 
of gnuplot, since the programme usually is used for working 
with one datapoint (row) at the same time. 

The 'easiest' way (or at least the way I would solute this 
problem) is to add another column, which lists the values 
of (energy-1). This may be done automatically by a small, 
self written programme or by a script for your favourite 
table calculating programme. You could refer to this new 
column simply by using using ;-)

gnuplot supports the facilities provided by the 
scanf-library. I used these to split up a column value 
within a datapoint into several values, but I'm not sure, 
wheter scanf is able to "look" a row above. Maybe you'd 
like to ask gnuplots help about using and scanf. 

Hope that helps
Lars