Re: gnuplot-4.4.0-rc1 breaks gnuplot script

[Ethan M. <merritt@u.washington.edu>]

On Friday 12 February 2010 09:58:45 Teo S Bernhard wrote:
> Problem:
> Gnuplot script that set parameter repeatedly in plot command to address the
> data index (within a data file) does not work when using gnuplot version
> 4.4.0-rc1.
> It works in 4.2 version and, from memory, did also work in version 4.3. See
> the below shortened example reproducing the error message:
> 
> 
> # file: trial.gpl
> f(x)=x
> plot a=1, \
>      f(x)*a   title "data from index a=1" w l lw 2 lt a ,  a=a+1,       \
>      f(x)*a   title "data from index a=2" w l lw 2 lt a ,  a=a+1,       \
>      a=0

Please see Bug #2907028
  https://sourceforge.net/tracker/?func=detail&aid=2907028&group_id=2055&atid=102055

So far as I can tell from running old versions of gnuplot (back to 3.7),
it never did work correctly to increment a variable multiple times inside
a plot command.

The good news is that in version 4.4 you can do this easily using the construct
   plot for [a=1:2] f(x)*a   title "data from index a=1" w l lw 2 lt a


> pause -1 "Continue?"
> 
> #
> # gnuplot 4.2 patchlevel 5 accepts the above. I believe that also
> # gnuplot 4.3 accepted this.
> #
> # gnuplot-4.4.0 patchlevel 0-rc1 give error:
> #    "trial.gpl", line 6: function to plot expected
> #
> #
> #  It works if I add a dummy curve after a=0, so that last line
> #  becomes:
> #                   a=0, x/0
> #
> exit
> 
> Best regards
> Teo
> 



-- 
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle 98195-7742