[Maxima-bugs] [ maxima-Bugs-618280 ] entier(-1.0)==(fix -1.0) = -2 (!!!)

[<no...@so...>]

Bugs item #618280, was opened at 2002-10-03 18:10
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=104933&aid=618280&group_id=4933

Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Stavros Macrakis (macrakis)
Assigned to: Nobody/Anonymous (nobody)
Summary: entier(-1.0)==(fix -1.0) = -2 (!!!)

Initial Comment:
Entier(-1) = -1 (correct)
Entier(-1.0) = -2 (!!!!)

The problem comes from the Fix function in clmacs.

It should be rewritten this way (the simple, clean, 
possibly a tiny bit inefficient way):

(defun fix (n)
  (cond ((integerp n) n)
           ((< n 0) 
            (cond ((= n (truncate n)) (truncate n))
                     (t (- (truncate n) 1))))
           (t (values (truncate n)))))

or this way (the old-fashioned dirty way):

(defun fix (n)
  (cond ((integerp n) n)
           ((< n 0) 
            (cond ((= n (setq n (truncate n)))
                      n)
                     (t (- n 1))))
           (t (values (truncate n)))))

or this way (the new-fangled multiple return value way):

(defun fix (n)
  (cond ((integerp n) n)
	((< n 0) 
                 (multiple-value-bind (tr rem) (truncate n)
                      (cond ((= rem 0) tr)
                               (t (- tr 1)))))
	(t (values (truncate n)))))




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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=104933&aid=618280&group_id=4933