bugGNU Common Lisp - Bugs: bug #13068, strange behaviour with big numbers


bug #13068: strange behaviour with big numbers

Submitted by:  None
Submitted on:  Thu 12 May 2005 08:21:30 PM UTC  
Category: NoneSeverity: 3 - Normal
Item Group: NoneStatus: Fixed
Privacy: PublicAssigned to: None
Open/Closed: Closed

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Thu 21 Nov 2013 10:26:48 PM UTC, comment #1:

Thanks for your report! Fixed in the latest release, 2.6.10.

Camm Maguire <camm>
Project Administrator
Thu 12 May 2005 08:21:30 PM UTC, original submission:


I played around a little bit with fibonacci numbers. But when they get too large, the output gets strage (just special characters) and my terminal crashes.

I entered the following lines at toplevel:

(defun exponent-loop-matrix (x e n)
(if (eq e 0) n
(matrix-mult x x)
(ash e -1)
(if (eq 1 (logand e 1)) (matrix-mult n x) n))))

(defun matrix-mult (m n)
(let ((a (aref m 0)) (b (aref m 1)) (c (aref m 2))
(d (aref n 0)) (e (aref n 1)) (f (aref n 2)))
(vector (+ (* a d) (* b e)) (+ (* b d) (* c e)) (+ (* b e) (* c f)))))

(defun exponent-matrix (x e) (exponent-loop-matrix x e (vector 1 0 1)))

(defun fibonacci (n)
(aref (exponent-matrix (vector 1 1 0) (- n 1)) 0))

(compile 'fibonacci)
(compile 'exponent-matrix)
(compile 'exponent-loop-matrix)
(compile 'matrix-mult)

(fibonacci 3500000)

I am using GCL 2.6.6 (latest Debian package) on an i686 Debian GNU/Linux installation. Numbers below (fibonacci 3123698) work as exspected. (The bound is sometimes a little bit higher).

I hope this helps.



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    Follow 2 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Thu 21 Nov 2013 10:26:48 PM UTCcammStatusNone=>Fixed

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