Re: [tablix-list] schooltool bounty and/or bakeoff

From: John Winters <>
Date: Thu Oct 28 2004 - 10:01:22 CEST

On Thu, 2004-10-28 at 08:15, Tom Hoffman wrote:
> On Thu, 28 Oct 2004 07:32:41 +0100, John Winters <> wrote:
> > Now you can tell us how the USA model differs.
> Do the students literally choose which section own section of each
> class to take -- "I'll take English 9, at 9:00," or does the system
> work out which sections fit their overall schedule (so the student
> would select English 9, but the computer would pick the best section,
> maybe 9:00, maybe 10:00)? Or perhaps they don't have choices of
> multiple sections/meeting times for classes.

We don't allow students to pick times - that all comes out automatically
from the subject choices which they make.

To go into a bit more detail, the common method which I've seen (and
which I've been considering implementing as an enhancement to Tablix
because there doesn't seem to be direct support for it at present) is to
give students a list like this:

Group A
English, Maths, Geography, History, French, Physics

Group B
English, Maths, French, Chemistry, Latin, PE

Group C
Physics, Chemistry, Biology, PE, Business Studies

Group D
History, Geography, French, Physics

(Note, I just made these up and I can see looking at them that they
wouldn't actually be feasible, but I hope to give the general idea.)

The students can then pick one subject from each group (often called
columns) and their choices will then dictate their timetables. If they
can't get their desired choices by taking one from each group then they
can't do that particular combination - although the lists are designed
to make almost all likely combinations possible.

The timetabling task is then simply to schedule all the lessons in such
a way that when a lesson from column A is happening, no lesson from any
other column may happen, etc. Any subject which appears in two
different columns will have two sets of classes for it, and the column
from which you select the subject dictates which class you will attend.

Note (and this is a mistake which at least one timetabling package which
I've looked at makes) it is *not* necessary for all lessons from column
A to happen simultaneously - merely that lessons from different columns
don't happen at the same time. Obviously, all the lessons from a given
column will tend to happen at the same time, but it's often much easier
to find a slot when 5 out of 7 can happen than it is to find one when
all 7 can happen.

This is a feature which I see as lacking from Tablix. I raised it on
this list before but got no response. It would be nice to be able to
group proposed lessons and set up mutual exclusion relationships. You
create, say, 4 groups and then specify that they are mutually
exclusive. Two lessons from the same group can happen at the same time,
but two lessons from different groups can't.

AFAICS, the only way of doing this from Tablix at present is to set up
lots of explicit "Conflicts with" statements for each individual lesson,
which is a bore and hard to maintain. Have I missed an existing better
way of doing it?

> We'll get to the bottom of this eventually ;-)

It's rather interesting. I'm looking at re-working the way we do the
generation of the timetable so I want to know as much about alternative
approaches as possible.

Received on Thu Oct 28 10:41:22 2004

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