Re: [Gnuplot-info] Compute values with 'every'

[Alexander S. <ma...@st...>]

"set datafile missing NaN" should do the trick
and here's a small edit:
(int($0)%4 == 0 ? (y=$1,NaN) : int($0)%4 == 3 ? y/$1 : NaN)
else it would plot datum#1 every 4th line (starting first line) and
datum#1/datum#3 every 4th line (starting from the third line).

Cheers,
Alex

On Wed, 2 Dec 2020 at 14:21, Robert von Knobloch <bo...@en...> wrote:

> On 01/12/2020 16:29, Alexander Stangl wrote:
> > Hey,
> >
> > what about:
> >
> > y=NaN
> > 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, \
> >          file1 u 0:(int($0)%4==0 ? y=$1 : int($0)%4==2 ? $1*y : NaN) t
> > "50*100"
> >
> > Best,
> > Alex
> >
>
> Hi Alex, thanks for the code.
> It did not produce a visible plot for me, so I adjusted it a wee bit:
>
> y=NaN
> plot    file1 every 4::0 using 1 title "rr25" ls 1, \
>         file1 every 4::1 using 1 title "rr50" ls 3, \
>         file1 every 4::2 using 1 title "rr75" ls 5, \
>         file1 every 4::3 using 1 title "rr100" ls 7, \
>         file1 using 0:(int($0)%4 == 0 ? y=$1 : int($0)%4 == 3 ? y/$1 :
> NaN)
> title "rr100/rr50" ls 9
>
> I'm dividing, not multiplying but the result is the same:
>
> small pieces of plot trace between each 3rd and 0th (4th) entry the
> endpoints of these pieces don't seem to bear any numerical relationship
> to the data.
> Small picture attached, also to your direct mail as I think the list may
> not support pictures.
>
> I think I see the logic of your suggestion and cannot see any reason why
> it should not work (from reading the Gnuplot docs).
>
> Many thanks for your time,
>
> Bob
>