On 4/28/08, Dan Hatton <vi5u0-maxima at yahoo.co.uk> wrote:
plot2d(carg(eb(0.3,x,-0.025/Gamma,%pi/4.)),[x,0.,0.08],[gnuplot_term,table],[gnuplot_out_file,"ebplot2.dat"])
;
>
> (where eb() is a user-defined function), and got back the question
>
> Is 1935330952107 x - 220645654645148032 positive, negative, or
> zero?
Dan, Maxima wants to simplify some expression (probably within
sqrt or atan) and it's asking for your help (it can't deduce the
result by itself and apparently doesn't know how to proceed otherwise).
This is a serious misfeature IMNSHO.
In this particular case, you might be able to suppress the question
by getting Maxima to evaluate carg(whatever) only after assigning
a value to x, e.g.: foo(x) := carg(eb(0.3,x,-0.025/Gamma,%pi/4.));
then just name the function in the call to plot2d, i.e.: plot2d(foo,
[x, ...], ....);
A couple of random notes. (1) 4. represents the integer 4 in base 10;
it is not floating-point 4 --- that is 4.0 . (2) If you want to output a
table of values to a file, maybe it is more straightforward to avoid
plot2d, e.g.: xlist : makelist(i*0.0008, i, 0, 100); ylist : map(foo, xlist);
xy : transpose(matrix(xlist, ylist)); write_data(xy, "xy.txt");
HTH
Robert Dodier