Re: Problem (bug?) with "smooth frequency" and logscale in 4.0 and 4.1

[Hans-Bernhard B. <br...@ph...>]

Kostas Oikonomou wrote:

> set xrange [0:10]
> set logscale y
> plot 'j' using (floor($1)):($2) smooth frequency with points

First of all, a note: it's not very likely to be good idea to use 
'smooth frequency' with a y column that is not a constant.

"Smooth frequency" adds all applicable y values for a given x position 
and output that as the resulting data point.  The idea is that you can 
use a constant (1) as the y value, and thus obtain a count of numbers in 
a given x interval.

The problem in your example is that the filter gets fed with 
logarithmized y values if you 'set log y', i.e. it effectively 
*multiplies* the values, rather than adding them.   So at x=2, instead 
of 0.01+0.01+0.01=0.03, you get 0.01*0.01*0.01=1e-6.

Whether that's a bug or not lies in the eye of the beholder.  It's a 
strange, undocumented feature, but it may actually be useful to some 
people, in some situations ;-)  As a workaround, you can always do the 
number crunching outside gnuplot, or at least run the filter separately 
from the plot itself (--> 'help table'), which allows you to filter in 
linear y scale, but plot in log.