![](bga.png)
extension will be of course tailored to our API, which
will force us to have quite generic implementations
that can operate on any neighbourhoods, since they
express their moves through the sequence API. Sim-
ilarly, an appropriate set of generic neighbourhoods
operating on sequences must also be proposed to
make this sequence variable fully usable. So far, only
routing neighbourhoods have been implemented.
Our sequence variable features a checkpoint
mechanism that is useful for global constraints to per-
form pre-computations. As discussed above, there are
several policies on how to manage such checkpoints.
Our framework only implements one of these poli-
cies, but other policies can be added to the engine. Be-
sides, this mechanism is restricted to sequence vari-
ables. It should be made pervasive in the model, so
that invariants with other type of variables could also
perform such pre-computations.
This new variable type will be included in the
CBLS engine of OscaR 4.0 to be released in Spring
2017 (OscaR Team, 2012). With this additional
type of variable, we hope that OscaR.cbls will be
even more appealing both to users that benefit from
highly efficient global constraints in a declarative lo-
cal search engine, and to researchers who aim at de-
veloping new global constraints and will benefit from
the whole environment of OscaR.cbls, so they can fo-
cus on their own contribution. This implementation
will also offer a common benchmarking environment
to compare the efficiency of e.g. global constraints
within a standard setting.
ACKNOWLEDGEMENTS
This research was conducted under the SAMOBI
CWALITY research project from the Walloon Region
of Belgium (grant number 1610019).
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