[Help-glpk] [Fwd: Sets of arbitrary length sets in MathProg]

[Andrew Makhorin]

-------- Forwarded Message --------
From: Ben Mabey <address@hidden>
To: address@hidden
Subject: Sets of arbitrary length sets in MathProg
Date: Tue, 21 Feb 2012 09:29:23 -0700

Hi,
In my MathProg model I need to be able to specify sets of groups of 
workers that need to work with each other on a particular shift.  It 
doesn't matter what shift they work on, just that they work together.  I 
know how to model this but I don't know how to represent it with 
MathProg since it requires having a set of sets in which the children 
sets can be of 1..n length (but may not be all the same length). For 
additional context, I have the following declared:

   set WORKERS;
   set TASKS;
   param number_of_shifts integer > 0;
   param num_tasks_in_each_shift := (card(TASKS) / number_of_shifts) 
integer > 0;

In my case I want to be able to, in my data section, declare sets of 
workers that must work with each other which I call WORKER_CLIQUES.  
Ideally it would look something like this in my data section:

   set WORKERS := Jack Kate Sawyer Sun Juliet Richard Desmond Hugo;
   param number_of_shifts := 2;

   set WORKER_CLIQUES := (Sawyer, Juliet) (Jack,Kate,Hugo); # I want this!

Is it possible to have a set like WORKER_CLIQUES?  I don't know how I 
would declare the set, but it would be something like:

   set WORKER_CLIQUES within {i in WORKERS} dimen 
num_tasks_in_each_shift; # I know this is wrong..

I need to be able to limit the cardinality of each WORKER_CLIQUE to be 
equal to or less than num_tasks_in_each_shift.

This this possible to do in MathProg?

Thanks!

-Ben