Greatest common denominator

Does anyone know if it is possible and how to get the greatest common
denominated of more than two integers

Cheers

Greg

 

don't know if this is any help but found it in a few seconds on jeeves
http://www2.edc.org/makingmath/mathtools/euclid/euclid.asp

 

I thougth that was a simple question, but its not :<(

 

Hi Greg

Maybe somone has a more elegant solution, but this sould work:

Code:

(defun GetGCDfromList (Lst / TmpLst)
(foreach a Lst
(foreach b Lst
(setq TmpLst (cons (GetGCD a b) TmpLst))
)
)
(apply 'min TmpLst)
)

(defun GetGCD (Fst Nxt)
(cond
((zerop Nxt) Nxt)
((zerop (rem Fst Nxt)) Nxt)
((GetGCD Nxt (rem Fst Nxt)))
)
)

Use:
_$ (GetGCDfromList '(4 32 16 256 8))
4

Cheers

 

(gcd n n n)

-David

 

Error: To many arguments.

 

Hi David

If you are working with integers and values >0, you can use:

Code:

(defun GetGCDfromList (Lst / TmpLst)
(foreach a Lst
(foreach b Lst
(setq TmpLst (cons (gcd a b) TmpLst))
)
)
(apply 'min TmpLst)
)
[code]
otherwhise, you've to work with my 'GetGCD'...

Cheers

 

R12 thru R14 didn't do that. ??? -David

 

2005 help file reads "between two integers"

 

Hi David

Customization Guide R12-R14:
'Returns the gcd of two integers'
dig up my old books out the dust...;

Cheers

 

Hmmm.. It doesn't error out. Must have been a bug. -David

 

It was, apparently, an error in the docs before R2000. They fixed it by
changing the command rather than the docs. I always thought it was kinda
cool to be able to find the lcd of more than two integers at a time. Oh,
well.
___

 

Jurg,

Your a champion, I layed awake all last night trying to think of how to do
this. Thank you Very Much, thats twice in two days you've helped me.

Cheers

Greg

 

Jurg,

This works just the same...

(defun GetGCDfromList (Lst / TmpLst)
(foreach a Lst
(foreach b Lst
(setq TmpLst (cons (gcd a b) TmpLst))
)
)
(apply 'min TmpLst)
)


Cheers

Greg

 

Glad to help you...¦-)

Cheers

 

Hi Greg

With integers and values >0 yes, otherwise you've to apply my 'GetGCD'.

Cheers

 

Ah, I knew you'd have a reason.