BROGI, A. AND-parallelism without shared variables. Seventh International Conference on Logic Programming. MIT Press, p.306-324, 1990.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....mentioned [11, 17, 19, 29, 30, 31, 32] efforts which have been focusing on the static aspects (i.e. inheritance) of object oriented programming are described in [2, 9, 12, 16, 21, 33] The framework presented here should provide a theoretical basis for the integration of these two traditions. [10, 28, 8] provide also extensions of Prolog in the direction of object oriented and distributed programming where formulae with multiple heads are allowed; some of the ideas characterizing these approaches are interestingly related to ours, and indeed the systems described therein seem to be logically ....

A. Brogi. And-parallelism without shared variables. In Proc. of the 7th International Conference on Logic Programming, Jerusalem, Israel, 1990.

....using the C language, Quintus Prolog and LML. In a second phase, programs were only translated into C. Ciampolini et al. [10] have proposed DLO, a system to create distributed logic objects. The implementation translates DLO programs into clauses of a concurrent logic language called Rose [7]. The support to Rose execution is implemented on a MIMD distributed memory parallel architecture (transputer based Meiko Computing Surface) The runtime environment consists of a parallel abstract machine which is an extension of the WAM [1] Oz multiparadigm language [23] is used to create a ....

Brogi, A. AND-parallelism without shared variables. Seventh International Conference on Logic Programming. MIT Press, p.306-324, 1990.

....cons(X) c(X,Z) cexch(X) pexch( H Tp] Pi cexch( H Tc] prod(Tp) Pi cons(Tc) The reader will appreciate the ease of coding as opposed to that obtained by using the asynchronous communication of usual concurrent logic programming languages. Other examples have been programmed in [Br90], DD83] FLP84] Mo81] Mo82] and [Sa89] to further substantiate the above claim. Among them are semaphores, the seminal dining philosophers problem, generative communication in a Linda style and object oriented programming. 2 We turn in this paper to the semantic analysis of generalized ....

....that would allow synchronization to take place (suspension) The denotational semantics Den, defined as usual compositionally, further details the computation by handling hypotheses about the environment of goals. Generalized Horn clauses have already been presented in similar forms in [AP90] [Br90], Co88] DD83] FLP84] Mo81] Mo82] and [Sa89] The work reported here differs from them both from the language point of view and from the semantic point of view. From the language point of view, our language differs in two main respects. Firstly, it allows arbitrary sequential and parallel ....

[Article contains additional citation context not shown here]

Brogi A., And-parallelism without Shared Variables, Proc. of the 7th Int. Conf. on Logic Programming, 1990, pp. 306-321.

....induced by the absence of suitable concurrent goals that would allow synchronization to take place (suspension) In particular, the latter point is tackled by handling suitable hypotheses about the environment of goals. Extended Horn clauses have already been presented in similar forms in [2] [3], 4] 8] 10] 16] 17] and [19] The work reported here differs from them both from the language point of view and from the semantic point of view. From the language point of view, our language differs in three main respects. Firstly, it allows arbitrary sequential and parallel compositions ....

....by the corresponding body. It should be noted that this requirement, besides allowing to deal with unrestricted sequential composition, does not represent a real limitation as compared to the aforementioned languages. For example, the clauses A 1 A 2 A 3 and A 1 A 2 A 3 A 4 A 5 of Rose ([3]) may be rewritten respectively as A 1 Pi A 2 4 j A 3 Pi 4 and A 1 Pi A 2 4 j A 3 Pi A 4 k A 5 , with 4 denoting the empty conjunction of atoms. From the semantic point of view, our work differs both from related work issued from the logic programming tradition and from the metric ....

[Article contains additional citation context not shown here]

A. Brogi. And-Parallelism without Shared Variables. In D.H.D. Warren and P. Szeredi, editors, Proc. 7 th Int. Conf. on Logic Programming, pages 306--321, Jerusalem, Israel, 1990. The MIT Press.

....because of the mechanism of competing activation patterns. There is also no provision to define relations between blackboards in Shared Prolog. Other languages similar in spirit to the blackboard relations in Log include Gamma [2] LO [1] Communicating Clauses [16] and the mechanism proposed in [3]. All of them transform in one way or another a multiset of elements into another one. Rephrased in terms of our framework, they basically consist of taking active processes and passive data and of putting other processes and data as a result. LO has moreover provision for specifying the number of ....

A. Brogi. And-Parallelism without Shared Variables. In D.H.D. Warren and P. Szeredi, editors, Proc. Seventh International Conference on Logic Programming, pages 306--321, Jerusalem, Israel, 1990. The MIT Press.

....between concurrent logic processes and is accessed by means of Linda like primitives putting, testing and removing both passive data structures and active processes from it. Finally, to conclude this non exhaustive list of examples, the synchronous communication mechanism introduced in [1, 5, 15, 16] can also be viewed as another instance of this general resource based scheme. There, processes are simultaneously reduced to others and thus act as resources for their synchronizing partners. Although resources thus appear to be central, most of the above mentioned logic languages have handled ....

....for both its sequential and parallel versions. As noted in [8] finding a way to represent parallel and non deterministic actions is a real challenge, to which we believe to have given a solution. Finally, this paper grew up as a continuation of our previous work [15, 16] and its related work [5, 9]. As already suggested, one difference with this work is the clear separation between resource handling and logical treatment. As an interesting consequence, resource need not be considered as active data when they are not actually. Compare for instance the stack example of section 2 and that of ....

[Article contains additional citation context not shown here]

A. Brogi. And-Parallelism without Shared Variables. In D.H.D. Warren and P. Szeredi, editors, Proc. 7 th Int. Conf. on Logic Programming, pages 306--321, Jerusalem, Israel, 1990. The MIT Press.

....these semantics as simple as possible as well as in the main streams of logic programming semantics. However, communicating clauses and synchronized executions raise new problems, for which fresh solutions are proposed. Communicating clauses have already been presented in similar forms in [1] [2], 3] 6] 7] 13] 14] 15] 16] and [20] in the classical logic programming framework. As already said, this paper is a continuation of our previous work [13, 14] In those papers, synchronous communication is expressed in a global and centralized way by extending classical Horn clauses. ....

....to deal with unrestricted sequential composition and giving distributed expressions of synchronous communication, this requirement does not represent a real limitation as compared to the aforementioned languages. For example, the clauses A 1 A 2 A 3 and A 1 A 2 A 3 A 4 A 5 of Rose ([2]) may be rewritten respectively as u 1 : A 1 A 3 fA 2 : u 2 g u 2 : A 2 4 fA 1 : u 1 g and u 1 : A 1 A 3 fA 2 : u 2 g u 2 : A 2 A 4 k A 5 fA 1 : u 1 g; with 4 denoting the empty conjunction of atoms. Our work also differs from related work at the semantic standpoint. To our best ....

[Article contains additional citation context not shown here]

A. Brogi. And-Parallelism without Shared Variables. In D.H.D. Warren and P. Szeredi, editors, Proc. 7 th Int. Conf. on Logic Programming, pages 306--321, Jerusalem, Israel, 1990. The MIT Press.

....inherent in the formalism provides for an asynchronous concurrent computation. Multiple heads Horn clauses have been studied in the past out of linear logic (with set theoretical characterizations in mind instead of the monoidal ones proper of linear logic, semantically speaking) in particular in [6, 9]. A recent linear logic programming (object oriented) language, which is a superset of ours, is LO [3] 3 Adding a sequentiality mechanism: the language SMR Multiset rewriting is a powerful computational formalism. In this section we present SMR (Structured Multiset Rewriting) a language whose ....

Antonio Brogi. And-parallelism without shared variables. In D.H.D. Warren and P. Szeredi, editors, Logic Programming, Seventh International Conference, pages 306--321. The MIT Press, 1990.

....efficient implementations in parallel environments. An important feature of the language is its ability to express in a simple way the synchronization and the communication between different computational flows, opening the way to distributed programming, as has already been shown in [11] and [8] for similar languages. In our case however we have a declarative semantics for the symmetrical interactions. In fact in the last part of the paper we propose a semantics for the language obtained by instantiating the phase semantics of linear logic. The resulting abstract structure associated to ....

....semantics for the language obtained by instantiating the phase semantics of linear logic. The resulting abstract structure associated to programs allows to declaratively model the behaviour of our computations. By exploiting the similarities of our fragment with the language of Generalized Clauses [11, 8], a fixpoint characterization of the phase semantics is also presented. The paper is organized as follows. In subsection 1.1 we introduce linear logic and its proof system. In section 1.2 we introduce the definition of uniformity for multiple conclusions sequent systems. Section 2 shows the ....

[Article contains additional citation context not shown here]

A. Brogi. And-parallelism without shared variables. In D. H. D. Warren and P. Szeredi, editors, Proc. Seventh Int'l Conf. on Logic Programming, pages 306--319. The MIT Press, Cambridge, Mass., 1990.

....to [Coh88] at the very beginning of the development of Prolog in the early 70 s by Colmerauer and Kowalski, experiments were performed with clauses having multiple head atoms. More recently, clauses with multiple head atoms were proposed to model parallelism and distributed processing, e.g. [Br90, AnPa91], or objects [Con88, AnPa90] The similarity of the object oriented approaches with SiRs is merely syntactical. Rules about objects cannot be regarded as specifying constraint simplification. Object rules are supposed to model the change of objects, while SiRs model equivalence and implication of ....

Brogi A., AND-Parallelism without Shared Variables, Proc of the Seventh Intl Conf on Logic Programming MIT Press 1990, pp. 306-321.

....is made slightly more general by permitting the synchronisation of more than two partners. This framework, called Scc, is presented in [4] and its expressiveness has been demonstrated through the coding of a variety of examples. It has been argued that one advantage over related work such as [18, 13, 1, 5, 11], which introduce synchronisation by special operators and not by altering the behaviour of tell and ask primitives, is that Scc permits the specification of on what information the synchronisation should be made, rather than with whom. Synchronisation in Scc is thus data oriented as opposed to ....

Antonio Brogi. AND-Parallelism without shared variables. In Warren and Szeredi [21], pages 306--321.

....between concurrent logic processes and is accessed by means of Linda like primitives putting, testing and removing both passive data structures and active processes from it. Finally, to conclude this non exhaustive list of examples, the synchronous communication mechanism introduced in [5, 1, 15, 16] can also be viewed as another instance of this general resource based scheme. There, processes are simultaneously reduced to others and thus act as resources for their synchronizing partners. Although resources thus appear to be central, most of the above mentioned logic languages have handled ....

....for both its sequential and parallel versions. As noted in [8] finding a way to represent parallel and non deterministic actions is a real challenge, to which we believe to have given a solution. Finally, this paper grew up as a continuation of our previous work [15, 16] and its related work [9, 5]. As already suggested, one difference with this work is the clear separation between resource handling and logical treatment. As an interesting consequence, resource need not be considered as active data when they are not actually. Compare for instance the stack example of section 2 and that of ....

[Article contains additional citation context not shown here]

A. Brogi. And-Parallelism without Shared Variables. In D.H.D. Warren and P. Szeredi, editors, Proc. 7 th Int. Conf. on Logic Programming, pages 306--321, Jerusalem, Israel, 1990. The MIT Press.

....transformations can be applied concurrently to the multiset, thus making possible efficient implementations in parallel environments. The rewriting of a multiset of logical formulas is amenable to simple interpretations in terms of process synchronization and communication, as shown in [14] and in [10]. We think that this provides a declarative notion of symmetrical communication and open the way to distributed programming. In the last part of the paper we propose a semantics for the language obtained by instantiating the phase semantics of linear logic. The resulting abstract structure ....

....language obtained by instantiating the phase semantics of linear logic. The resulting abstract structure associated to programs allows to declaratively model the transformational behaviour of our computations. By exploiting the similarities of our fragment with the language of Generalized Clauses [14, 10], a declarative semantics modeling answer substitutions is also presented. The paper is organized as follows. In subsection 1.1 we introduce linear logic and its proof system. In section 1.2 we introduce the definition of uniformity for multiple conclusions sequent systems. Section 3 shows the ....

[Article contains additional citation context not shown here]

A. Brogi. And-parallelism without shared variables. In D. H. D. Warren and P. Szeredi, editors, Proc. Seventh Int'l Conf. on Logic Programming, pages 306--319. The MIT Press, Cambridge, Mass., 1990.

....On the one hand, de Boer et al. 3] has proposed non monotonic updates of the store and have studied compositional and fully abstract semantics for them. On the other hand, Saraswat proposed a synchronisation mechanism in his thesis ( 12] Briefly, his proposal as well as related ones ([10, 1, 2, 6]) are based on the idea of enriching clauses by multiple heads and bodies. They require for the purpose of reduction the presence of concurrent atoms which simultaneously unify with the heads. Synchronicity is thus expressed in these proposals through the coding of an explicit operator. This ....

Antonio Brogi. AND-Parallelism without shared variables. In Warren and Szeredi [14], pages 306--321.

No context found.

BROGI, A. AND-parallelism without shared variables. Seventh International Conference on Logic Programming. MIT Press, p.306-324, 1990.

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC