bug or not about plot2d([parametric, ...



El mar, 07-04-2009 a las 07:35 +0000, Robert Marik escribi?:
> Xiang Liu <hsiang.liu <at> gmail.com> writes:
> 
> > 
> > Note: from t --> tt. The first doesn't work!
> 
> Hello
> 
> Perhaps I do not understand all details, but if you look into plot.lisp file
> from maxima sources, then you can see that tt variable is somehow used
> internally for plotting.


These two variables are different; the one used in the plot2d command is internally represented as $tt.

At the beginning of function draw2d-parametric in plot.lisp we have this piece code:

  792   (cond ((and ($listp (setq tem (nth 4 param)))
  793               (symbolp (cadr tem))
  794               (eql ($length tem) 3)
  795               (<= (length (symbol-name (cadr tem))) 2))
  796          ;; sure looks like a range
  797          (setq range tem)))


I don't know way the length of the variable (included the $) must be
less or equal than 2.

Furthermore, I think that 

820     (setq f1 (coerce-float-fun (third param) `((mlist), (second trange))))
821     (setq f2 (coerce-float-fun (fourth param) `((mlist), (second trange))))

should be:
820     (setq f1 (coerce-float-fun (third param) `((mlist), (second range))))
821     (setq f2 (coerce-float-fun (fourth param) `((mlist), (second range))))

With these two changes, function plot2d works as expected. Maybe I'm missing something, but if nobody complains, I can make a commit.



-- 
Mario