[Gnuplot-info] Compute values with 'every'

[Robert v. K. <bo...@en...>]

Hi,
I am plotting groups of 4 lines of data.
I can plot the first datum of each line using:

plot	file1 every 4::0 using 1 title "25" ls 1, \
	file1 every 4::1 using 1 title "50" ls 3, \
	file1 every 4::2 using 1 title "75" ls 5, \
	file1 every 4::3 using 1 title "100" ls 7

Which works fine for the whole file of 50 or so entries

What I would like to be able to do is to add a computed line e.g. the 
result of datum#1 in the first of the 4 block multiplied by datum#1 of 
the third block (for the whole file).

Is there a method of doing this?

Regards,
Robert von Knobloch