The Basic Andorra Model proposed in PEPMA achieves early and parallel execution of dependent goals, thus focusing on Dependent And-Parallelism (DAP). This has been extended to also include independent and-parallelism in a new framework now called Extended Andorra Model (EAM). The EAM, being a very rich model, represents a fairly large departure from conventional parallel Prolog models and implementation techniques. Other more conventional and well understood models being studied in the context of PEPMA project: the Muse and Aurora models, which exploit Or-Parallelism, and the &-Prolog model, exploiting independent and-parallelism. In the spirit of achieving some of the capabilities of the EAM while preserving the efficiency of these models and combining their capabilities, two new models have been developed by UPM in PEPMA, namely the ACE model and the IDIOM model.
IDIOM is aimed at combining all the three forms of parallelism (Dependent and Independent And- and Or-Parallelism), using well-understood implementation techniques. IDIOM is based on previous existing models, in particular in the Andorra-I and &-Prolog models for DAP and IAP and in the Aurora model for Or-Parallelism [5]
The ACE model is aimed at combining Independent and-parallelism and Or-Parallelism in a very efficient way. It is based also in previous models, which already have efficient implementations exploiting one and the other forms of parallelism separately: the &-Prolog and Muse models. As mentioned in section 3, this combination may be specially relevant from a commercial exploitation point of view [4].