[gecode-users] Optimization in GECODE

[Guido Tack]

Hi.

> I'm implementing a scheduling problem with start (s), duration (d),  
> end(e), setup times, for n jobs. I would like to find the minimum  
> scheduling time from s[0] to s[n-1] and e[0] to e[n-1]. I have set  
> it up such that e[n-1] contains the largest time point and I have  
> attempted BAB with constrain to minimize e[n-1]. I realize that  
> this only attempts different values for e[n-1] and does not try  
> different branchings for the s and e variables. How can I do this,  
> i.e., try different branchings to find a minimum?

Do you use a branching in your problem script? The Gecode search  
engines do not automatically instantiate variables, you must have a  
call to "branch" in order to set up the variable and value selection  
strategy. Also, you have to make sure that the branching instantiates  
all variables which are not necessarlily instantiated through  
propagation.

Cheers,
	Guido

-- 
Guido Tack
Programming Systems Lab, Saarland University, Germany
http://www.ps.uni-sb.de/~tack