>>>>> "Raymond" == Raymond Toy <toy@rtp.ericsson.se> writes:
Raymond> Several issues about plotting follow.
Raymond> In bug 552724 there is an example plot:
Raymond> plot2d([5-x^2,x+3],[x,-2,1]);
Raymond> With both openmath, the range of y is limited to -3 to +3 by the plot
Raymond> options. I think this is a bug. We shouldn't limit the y range unless
Raymond> specifically told to.
I've changed this so the default limit is arbitrarily
most-positive-double-float/1024. Using plain
most-positive-double-float cuases overflows in draw2d, so I used some
smaller number.
Raymond> If I specify
Raymond> plot2d([5-x^2],[x,-2,1],[y,-5,5])
Raymond> this produces the desired openmath plot. However, if I want to use
Raymond> gnuplot, the command
Raymond> plot2d([5-x^2],[x,-2,1],[y,-5,5,plot_format,gnuplot])
Raymond> produces an error because maxima wants just 2 items after y. I think
Raymond> this is a bug. Making plot_format come first fixes this. I think we
Raymond> should really specify the y option as y,[-5,5] instead of y,-5,5.
How embarrasing! plot2d takes many separate option parameters so this
is supposed to be like
plot2d([5-x^2],[x,-2,1],[y,-5,5],[plot_format,gnuplot])
which works. No changes need to be made.
Raymond> Also, if you use gnuplot, no plot is actually produced. I think the
Raymond> reason is that what maxima writes out includes lines like
Raymond> move x y
Raymond> where x and y are numbers. These aren't valid gnuplot values, so I
Raymond> think gnuplot just gives up. I have a hack to not print these lines,
For now, I just disable printing of these lines when the plot format
is gnuplot.
Raymond> Finally, it's impossible for the average person to figure out how to
Raymond> use plot2d because describe just says:
Raymond> - Function: PLOT2D (expr,range,...,options,..)
The info file contains the information, but describe doesn't seem to
want to display it. I'll have to look into this.
Ray