From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Clemente <n142857@gmail.com>
Subject: Re: Time computation errors
Date: Wed, 08 Apr 2009 00:37:55 +0200
Message-ID: <87ocv8dr98.fsf@gmail.com>
References: <u63hg62rd.fsf@missioncriticalit.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Return-path: <emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org>
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1LrJvE-0006ot-7q
	for emacs-orgmode@gnu.org; Tue, 07 Apr 2009 18:37:36 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1LrJv9-0006mY-MZ
	for emacs-orgmode@gnu.org; Tue, 07 Apr 2009 18:37:35 -0400
Received: from [199.232.76.173] (port=50915 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1LrJv9-0006mQ-GK
	for emacs-orgmode@gnu.org; Tue, 07 Apr 2009 18:37:31 -0400
Received: from mail-fx0-f166.google.com ([209.85.220.166]:58618)
	by monty-python.gnu.org with esmtp (Exim 4.60)
	(envelope-from <n142857@gmail.com>) id 1LrJv9-0008DR-1M
	for emacs-orgmode@gnu.org; Tue, 07 Apr 2009 18:37:31 -0400
Received: by fxm10 with SMTP id 10so2906628fxm.42
	for <emacs-orgmode@gnu.org>; Tue, 07 Apr 2009 15:37:30 -0700 (PDT)
In-Reply-To: <u63hg62rd.fsf@missioncriticalit.com> (Francesco Pizzolante's
	message of "Tue, 07 Apr 2009 14:29:21 +0200")
List-Id: "General discussions about Org-mode." <emacs-orgmode.gnu.org>
List-Unsubscribe: <http://lists.gnu.org/mailman/listinfo/emacs-orgmode>,
	<mailto:emacs-orgmode-request@gnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/emacs-orgmode>
List-Post: <mailto:emacs-orgmode@gnu.org>
List-Help: <mailto:emacs-orgmode-request@gnu.org?subject=help>
List-Subscribe: <http://lists.gnu.org/mailman/listinfo/emacs-orgmode>,
	<mailto:emacs-orgmode-request@gnu.org?subject=subscribe>
Sender: emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org
Errors-To: emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org
To: Francesco Pizzolante <fpz@missioncriticalit.com>
Cc: mailing-list-org-mode <emacs-orgmode@gnu.org>

El mar, abr 07 2009, Francesco Pizzolante va escriure:
> Consider the following example:
>
> | Description | Time1 | Time2 | Time3  |
> |-------------+-------+-------+--------|
> | * Test      |  3:30 |  3:00 | #ERROR |
> | *** Item 1  | -1:30 |  1:00 | #ERROR |
> | *** Item 2  |  4:00 |  2:00 | #ERROR |
> #+TBLFM: $4=3D$2+$3

  The problem is that calc (the package used by org-mode to do math calcula=
tions) sees 3:30 as a fraction: three thirtieths =3D 3/30 =3D 1/10 =3D 0.1

>
> 1) The sum of Time1 for Test headline is wrong: 3:30 instead of
>    2:30;
>
  (-1/30) + (4/30) =3D (-1+4)/30 =3D -3/30 =E2=86=92 -3:30


> 2) I'm unable to sum times through a formula (see Time3 column).
>    The same formula works perfectly when you replace times with
>    integers.
>
  3:00 is 3/0 and gives an error (as a fraction it is =E2=80=9Ebad format=
=E2=80=9C to calc, not infinite=E2=80=A6).


  You can do more tests with: M-x calc RET


  According to the Calc manual:
The default format for HMS values is `hours@ mins' secs"'.


  So this makes calc happy:

| Description | Time1   | Time2  | Time3       |
|-------------+---------+--------+-------------|
| * Test      | 3@ 30'  | 3@ 00' | 6@ 30' 0"   |
| *** Item 1  | -1@ 30' | 1@ 00' | -1@ -30' 0" |
| *** Item 2  | 4@ 00'  | 2@ 00' | 6@ 0' 0"    |
#+TBLFM: $4=3D$2+$3


  (The negative time is however incorrect).

  I think it will be easier to use directly forms like 00:30 or the <2009-0=
4-08 mi=C3=A9 00:33> from org-mode, and make your own functions from there.
  Anyway, org tracks more times and dates than fractions, so 00:30 could be=
 also understood by org as a time.


-- Daniel