[gecode-users] Memory management

[Guido Tack]

benoitlaurent at neuf.fr wrote:

> Hello,
> I am working on a scheduling problem. On the instances I have to  
> deal with, I can reach a number of constraints of 500 000. During  
> the search process, the memory usage is very high, which eventually  
> renders my operating system unstable. Is it possible to solve this  
> problem ? How ?

500000 constraints is definitely a lot.  One way to save memory (which  
would also help performance) is to try remodeling with global  
constraints - of course, that depends on whether there are suitable  
global constraints for your problem.  The second thing you could try  
is to play with the recomputation parameters c-d and a-d.

For experimenting, I'd suggest limiting the amount of memory the OS  
may allocate to the process, so that you can always safely terminate  
it.  On unix systems, you can use the ulimit command (maybe there's  
something similar for Windows, too).

> I am not sure to understand the update method. I use many auxilliary  
> variables in my model. Must they all be copied in the update method ?

You only have to copy the variables that constitute the solution, e.g.  
those that you want to output.

Cheers,
	Guido

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