[Gnuplot-info] drifting of floor function

[seb_kramm <seb...@ya...>]

Hello gnuplot users,

While trying to plot a sawtooth wave (with 4.6 on Ubuntu), I noticed that the 
following plot:
   plot [0:10] x-floor(x)
produces some kind of vertical drifting, that gets magically reset at the end of the 
plot (whatever the x range, actually). (see attached png)

I tried also
   plot [0:10] x-1.0*floor(x)
to cast the int to floating-point, didn't change anything.

This seems to be related to the number of samples. Indeed, 'set samples 1000' solves 
the problem. But I was wondering if such a behaviour is normal ?
I understand that the number of samples can be changed to set the plot accuracy vs. 
computing time tradeoff, but I didn't expect that that parameter could produce 
"wrong" results if incorrectly set.

I consider myself as a rather experienced gnuplot user, and it took me some time to 
fix this issue, a newbie might have struggled with this during hours on such a simple 
thing (and would probably have accused gnuplot of being buggy...)

What do you think ? Is it worth fixing something (of course, in the case it *could* 
be fixed)? Or do you think it is okay this way ?


Regards,