plot problems



> above everything was OK with plot3d, but below the only 
> difference is single replacement of 0.5 with 1/2 and this 
> causes the error message.

I believe this bug has been fixed.

If you put the code below into a file named "plotfloatfix.lisp" and
execute load("...pathname.../plotfloatfix.lisp"), that should fix the
problem.  The Lisp function 'float' has been changed to the Maxima
function '$float', which knows about Maxima rationals, Maxima bigfloats,
etc.

       -s


(defun coerce-float-fun (expr &optional lvars)
  (cond ((and (consp expr) (functionp expr))
	 expr)
	((and (symbolp expr) (not (member expr lvars)))
	 (cond ((fboundp expr) expr)
	       (t
		(let* ((mexpr (mget expr 'mexpr))
		       (args (nth 1 mexpr)))
		  (or mexpr (merror "Undefined function ~a" expr))
		(coerce `(lambda ,(cdr args)
			     (declare (special ,@(cdr args)))
			     ($float ($realpart(meval* ',(nth 2 mexpr)))
1d0))
			  'function)))))
	(t
	 (let ((vars (or lvars ($sort ($listofvars expr))))
	       ;(na (gensym "TMPF"))
		)
	   (coerce `(lambda ,(cdr vars) (declare (special ,@(cdr vars)))
			($float ($realpart (meval* ',expr)) 1d0))
		   'function)))))