Isabel Dorta

MALLBA: a library of skeletons for combinatorial optimisation

The MALLBA project tackles the resolution of combinatorial optimization problems using algorithmic skeletons implemented in C++. mallba offers three families of generic resolution methods: exact, heuristic and hybrid. Moreover, for each resolution method, MALLBA provides three different implementations: sequential, parallel for local area networks, and parallel for wide area networks (currently under development). This paper explains the architecture of the MALLBA library, presents some of its skeletons, and offers several computational results to show the viability of the approach.

Efficient parallel LAN/WAN algorithms for optimization: the MALLBA project

The MALLBA project tackles the resolution of combinatorial optimization problems using generic algorithmic skeletons implemented in C++. A skeleton in the MALLBA library implements an optimization method in one of the three families of generic optimization techniques offered: exact, heuristic and hybrid. Moreover, for each of those methods, MALLBA provides three different implementations: sequential, parallel for Local Area Networks, and parallel for Wide Area Networks. This paper introduces the architecture of the MALLBA library, details some of the implemented skeletons, and offers computational results for some classical optimization problems to show the viability of our library. Among other conclusions, we claim that the design used to develop the optimization techniques included in the library is generic and efficient at the same time.

Parallel skeletons for divide-and-conquer and branch-and-bound techniques

The article describes the parallel implementation of skeletons for the divide-and-conquer and branch-and-bound techniques. The user has to choose a paradigm and has to specify for it the type of the problem, the type of solution and the specific characteristics of the technique using the C++ programming language. This information is combined with the provided resolution skeleton to obtain a sequential program and a parallel program. The paper describes the parallel implementation of the skeletons using MPI. Computational results on a Linux-cluster of PCs, Cray T3E and Origin 3000 are presented.

A comparison between MPI and OpenMP Branch-and-Bound skeletons

This article describes and compares two parallel implementations of Branch-and-Bound skeletons. Using the C++ programming language, the user has to specify the type of the problem, the type of the solution and the specific characteristics of the branch-and-bound technique. This information is combined with the provided resolution skeletons to obtain a distributed and a shared parallel programs. MPI has been used to develop the message passing algorithm and for the shared memory one OpenMP has been chosen. Computational results for the 0/1 Knapsack Problem on a Sunfire 6800 SMP, a Origin 3000 and a PCs cluster are presented.

Parallel Branch-and-Bound Skeletons: Message Passing and Shared Memory Implementations

The aim of this article is to describe the design and the implementation of skeletons for the Branch-and-Bound technique. The library developed provides sequential and parallel resolution patterns to solve optimization problems through this technique on a wide range of parallel computing platforms. To use the skeletons proposed to solve a particular problem, the skeleton filler has to specify the type of the problem, the type of the solution and the specific characteristics of this paradigm using the C++ programming language, and the user does not need to have any knowledge in parallelizations techniques. This paper describes the sequential and the parallel algorithms for message passing and shared memory platforms, and shows computational results for the 0-1 knapsack problem on an Origin 3000.

Performance analysis of Branch-and-Bound skeletons

This article proposes a study of load balancing and communication pattern for Branch-and-Bound algorithms. Concretely, sequential and parallel generic skeletons to implement this algorithmic technique are presented. To accomplish the work the call and paraver tools are used. call allows us to annotate the code by hand at the special points with a complexity function. Also, some computational results are presented.

Performance analysis of branch-and-bound skeletons

This article proposes a study of load balancing and communication pattern for branch-and-bound algorithms. Concretely, sequential and parallel generic skeletons to implement this algorithmic technique are presented. To accomplish the work the CALL and PARAVER tools are used. CALL allows to annotate the code by hand at the special points with a complexity function. Also, some computational results are presented.

MPI and OpenMP implementations of branch-and-bound skeletons

Publisher Summary This chapter describes two skeletons to solve optimization problems using the branch-and-bound technique. Sequential and parallel code of the invariant part of the solvers is provided. The implementation of the skeletons is in C++, and is divided into two different parts: one, that implements the resolution pattern provided by the library, and the second part, which the user has to complete with the particular characteristics of the problem to solve. This second part is used by the resolution pattern and acts as a link. Required classes are used to store the basic data of the algorithm. The solvers are implemented by provided classes. There is one skeleton in the class hierarchy, which is implemented using MPI, and another one using OpenMP. Once the user has represented the problem, two parallel solvers are obtained without any additional effort: one, using the message passing paradigm, and other with the shared memory one. An algorithm for the resolution of the classic 0–1 knapsack problem has been implemented using the skeleton proposed. The obtained computational results using an Origin 3000 are discussed in the chapter.