Skip site navigation (1) Skip section navigation (2)

Re: Arbitrary precision modulo operation

From: "Dann Corbit" <DCorbit(at)connx(dot)com>
To: "Bruno Wolff III" <bruno(at)wolff(dot)to>,"Chadwick Boggs" <chadwickboggs(at)yahoo(dot)com>
Cc: <pgsql-general(at)postgresql(dot)org>
Subject: Re: Arbitrary precision modulo operation
Date: 2004-04-26 19:48:45
Message-ID: D90A5A6C612A39408103E6ECDD77B829408D69@voyager.corporate.connx.com (view raw or flat)
Thread:
Lists: pgsql-general
Maple output:
y := 123456789012345678901234567890 mod 123;
                               y := 117

CONNX output (which uses qfloat by S. Moshier):
select mod(123456789012345678901234567890 , 123) {nopassthrough}
117 

PariGP output:
? Mod(123456789012345678901234567890, 123)
%4 = Mod(117, 123)
?

> -----Original Message-----
> From: Bruno Wolff III [mailto:bruno(at)wolff(dot)to] 
> Sent: Monday, April 26, 2004 10:42 AM
> To: Chadwick Boggs
> Cc: pgsql-general(at)postgresql(dot)org
> Subject: Re: [GENERAL] Arbitrary precision modulo operation
> 
> 
> On Mon, Apr 26, 2004 at 13:30:17 -0400,
>   Chadwick Boggs <chadwickboggs(at)yahoo(dot)com> wrote:
> > Example of wrong results from modulo operation of arbitrary 
> precision
> > numbers:
> > 
> > # select '123456789012345678901234567890'::numeric % 123; ?column?
> > ----------
> >       -6
> > (1 row)
> > 
> > # select mod('123456789012345678901234567890'::numeric, 123); mod
> > -----
> >  -6
> > (1 row)
> > 
> > The correct result (at least according to another, unnamed, RDBMS):
> > 
> > > select '123456789012345678901234567890' % 123;
> > +----------------------------------------+
> > | '123456789012345678901234567890' % 123 |
> > +----------------------------------------+
> > |                                     58 |
> > +----------------------------------------+
> > 1 row in set (0.00 sec)
> 
> I checked this with bc and I got -6 (and 117) as being 
> correct. I would think the other database was wrong.
> 
> It wouldn't happen to be MYSQL would it?
> 
> ---------------------------(end of 
> broadcast)---------------------------
> TIP 1: subscribe and unsubscribe commands go to 
> majordomo(at)postgresql(dot)org
> 

Responses

pgsql-general by date

Next:From: Guy FraserDate: 2004-04-26 19:58:57
Subject: Re: 7.3.4 on Linux: UPDATE .. foo=foo+1 degrades massivly
Previous:From: Alvaro HerreraDate: 2004-04-26 19:46:45
Subject: Re: 7.3.4 on Linux: UPDATE .. foo=foo+1 degrades massivly

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group