[Gnuplot-bugs] new assign() function.

[<pl...@pi...>]

Hi,

in my continued use and testing of assign() patch I was found a limitati=
on  =

in using this technique called from plot. This does not ammount to a bug=
  =

in assign(), which seems to be pretty solid.


The problem occurs in using replot. Since the line defining the initial =
 =

conditions only gets executed when loading the .gnu file, calling replot=
  =

here gives me an incorrect result by retaining that last values of start=
ed  =

and hence prev_x, prev_y :

A work around would be to plot some dummy data before the main plot that=
  =

called another function where the variables are initialised. In my case =
it  =

is sufficient to reassign started=3D0 as shown. There may be a more eleg=
ant  =

solution.


#started=3D0;
reset(x)=3Dassign("started",0.0); # called by dummy plot to ensure  =

initialisation on replot
add_aug(x,y)=3Dassign("area",(started>0)?\
                                       area + (x-prev_x)*(y+prev_y)/2.0 =
 =

+ 0.0*(assign("prev_x",x) + assign("prev_y",y) ) \
                                     :  0.0*( assign("started",1)  =

+ assign("prev_x",x) + assign("prev_y",y) ) \
                    ) ;

plot  "init.data"  using 1:(reset(0)) t "" \
,  datafile   using  =

1:(add_aug(strptime("%H:%M",stringcolumn(1))/3600,P( Th4($3-2.0) - Th5($=
2)  =

))/10) axes x1y2  with lines s f t "Energy*100/kWh"


best regards/