Problem (bug?) with "smooth frequency" and logscale in 4.0 and 4.1 From: Kostas Oikonomou - 2005-12-18 22:20 ```(I posted this to gnuplot-bugs, but I see a lot of spam there, so I am re-posting here.) Hello, I have discovered a problem, perhaps a bug, with the following: set xrange [0:10] set logscale y plot 'j' using (floor(\$1)):(\$2) smooth frequency with points where the 'j' file is: 1 0.09 2 0.01 2.1 0.01 2.3 0.01 3 0.02 6 0.01 6.5 0.01 8 0.001 9 0.001 9.1 0.002 The result I get is very wrong: e.g., at x=2, I get y=1e-6. And at x=9, I get 2e-6. When logscale y is disabled, the results look correct. Am I doing something wrong? Or is this a bug? *I do not subscribe to the list, so please CC me in your reply.* Kostas ```
 Re: Problem (bug?) with "smooth frequency" and logscale in 4.0 and 4.1 From: Hans-Bernhard Broeker - 2005-12-19 12:40 ```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. ```