Re: Adding normalise to gnuplot

[Ethan A M. <sf...@us...>]

On Monday, 28 April, 2014 11:59:27 Jon Gjengset wrote:
> > >> However, if you want to do this sort of thing it does not require a
> > >> patch to gnuplot, just use a function.
> > >>
> > >> max(x) =(if (x>biggest)?biggest=max:(x))
> > >> biggest=-1e-134; plot datafile 1:max($2)
> > >> plot datafile 1:($2/biggest)
> > >
> > > Ah, of course, why didn't I think of that?!
> > 
> > Thats also somthing which can be done with the stats command:
> > 
> > stats datafile using 2
> > plot datafile using 1:($2/STATS_max)
> 
> Actually, there is one use-case not covered by these approaches, and
> that is when doing a "live" plot where replot is called repeatedly and
> the underlying datafile changes. In these situations (unless I'm
> mistaken), STATS_MAX/biggest won't be recomputed, and so the scaling
> will be incorrect. A smoothing filter would continue to work in this
> case. Any thoughts on how rescaling on replot might be achieved without
> a patch?

Not precisely what you ask for, but very close to it

set autoscale noextend
set yrange [0:1]
set ytics .1
set datafile volatile

plot FOO axes x1y2 with line
set y2range[GPVAL_DATA_Y2_MIN:GPVAL_DATA_Y2_DATA_MAX]
refresh
pause -1

This doesn't actually rescale the data, but it maps the values against
the range [0:1] along the y axis.   There would be a flash of data using
the previous scale before the "refresh" remaps and redraws it.

	Ethan