[gecode-users] Propagator

[Jan Kelbel]

Hello,

some months ago I implemented N-ary propagator (it is that edge-finder). 
When I used it to solve larger problem instances, I noticed that it 
consumes memory in rate of about 1MB/s.
I tested it in Gecode 2.2.0 (where it was even about 3MB/s) and in 
Gecode 3.1.0., using MS Visual C++ 2008.

This propagator is inherited from class NaryPropagator. In the propagate 
method, there is an array for sorting, which is created using the Region 
allocation.

When I changed the edge-finder to inherit directly from the class 
Propagator, the growing memory consumption disappeared.

My question is, are there some rules, what should be implemented in 
propagator inherited from NaryPropagator in order allocate/dealocate 
memory correctly?


My second question (set of questions) is related to Val propagator for 
cumulatives constrait, which is my study material for implementation of 
scheduling constraints.
1) in Val::propagate()  file cumulatives/val.hpp
at line 276 there is a test if all the variables are assigned. Is there 
a reason why in case of subsumed = true; the function ES_SUBSUMED() is 
called  as late as at line 386?

2) Why there is no ES_FIX return from the Val::propagate() method?
In the documentation is that when the propagator computes fixpoint, it 
should return ES_FIX.
Is the reason that checking whether fixpoint is reached is expensive, 
and the propagation scheduler arranges that the propagation is not 
executed too many times?

Thank you.

Regards, Jan