Re: [Gnuplot-info] Scaling column data with data point

[Thomas S. <t.s...@fz...>]

Saurabh T <saurabh <at> hotmail.com> writes:
>
> I have a simple n-column data file, but instead of plotting ($1):($2) etc, I
want to plot ($1):($2/x) where x
> is the data point in the first row of column 2. Similarly for $3, $4 and so on
- in different plots. Thus
> basically I want to be able to scale column data by the first item in the
column. (I do understand and expect
> that the first data point will always show up as 1 in the plot).
> 
> Is this possible with gnuplot or do I have to preprocess my data file to
achieve this?
> 
> Thank you.

store the 1st value in the column into the variable 'x'
when reading the 1st row ('$0==0'):

plot 'datafilename' using 1:($0==0?x=$2:0 , $2/x)