[Help-glpk] Re: How to make consecutive variables take a certain value?

[Michael Hennebry]

On Fri, 30 Nov 2007, ican.ozgur wrote:

> On Friday 30 November 2007 07:32:15 Oscar Gustafsson wrote:
> > On Thu, 29 Nov 2007, Michael Hennebry wrote:
> > > Mathematically correct, but one should go for a tighter linear
> > > relaxation. x[d,h]<=x[d,h+1]
> > > x[d,h]<=x[d,h+2]
> > > With this formulation, the latter constraint is redundant.
> > > x[d,h]<=x[d,h+1] where d indexes a day and h and h+1 index hours.
> >
> > Won't this force all the remaining hours of the day to be one?
> >
> > On the other hand as the question is formulated it is supposedly what is
> > going to happen.

Yup.  Yup.

> The problem is a timetabling problem, and indeed there are three
> indices "x_dhc" standing for day,hours and classroom and there are sessions
> which has 2, 3 and 4 hours length of duration .I'm trying to allocate
> available hours of every classroom in a week.

Probably what you want are binaries based on start times.
You don't need to explicitly mark every period of a class.

-- 
Mike   address@hidden
"Horse guts never lie."  -- Cherek Bear-Shoulders