On Wed, Oct 15, 2025 at 3:15 AM Artur T. <atecon@posteo.de> wrote:

I'm encountering an error with the recent gretl snapshot (v2025c) related to the gnuplot command. The problem arises when using some options like --dummy and/or --factorized with discrete series.

# This returns an error "Invalid argument":
gnuplot gdpgrow school OECD --factorized=OECD --output=display

Sorry, I missed that point. But the error message is correct in this case.

When the --factorized option is given the factor series is always
taken to be the last-named one, here OECD. When a parameter is
appended to the flag that means that factorization should be limited
to the series named by the parameter. This inflection is applicable
only if the command list contains more than three series. For example

gnuplot y1 y2 x fac --factorized=y1

means y1 and y2 should be plotted against x, with y1 factorized by fac
and y2 not factorized. I think this is reasonably clear from the
documentation. (If "=y1" were not added, both y1 and y2 would be
factorized.)