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Parallel Implementations of the Complex-RF Algorithm
Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering.
Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering.ORCID iD: 0000-0002-2315-0680
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Even though direct-search optimization methods are more difficult to parallelize than population-based methods, there are many unexploited opportunities. Five methods for parallelizing the Complex-RF methods have been implemented and evaluated. Three methods are based on the unchanged original algorithm, while two require modifications. The methods have been tested on two test function and one real simulation model. An analysis of the algorithm has been performed. This provides a basis for parametrization of the parallel methods. Without changing the original algorithm, speed-up of 2.5-3 is achieved. With allowing modifications, a speed-up of up to 5 is obtained without significantly reducing the probability of finding the global minimum. Speed-up does not scale linear to the number of threads. When more threads are added, parallelization efficiency decreases. However, a comparison with a particle swarm method shows that Complex-RF performs better regardless of the number of threads, due to its fast convergence rate.

Keyword [en]
Parallel optimization, direct-search, simplex, Complex-RF
National Category
Electrical Engineering, Electronic Engineering, Information Engineering Fluid Mechanics and Acoustics
Identifiers
URN: urn:nbn:se:liu:diva-122751OAI: oai:DiVA.org:liu-122751DiVA: diva2:872642
Available from: 2015-11-19 Created: 2015-11-19 Last updated: 2015-11-19Bibliographically approved
In thesis
1. Distributed System Simulation Methods: For Model-Based Product Development
Open this publication in new window or tab >>Distributed System Simulation Methods: For Model-Based Product Development
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Distributed system simulation can increase performance, re-usability and modularity in model-based product development. This thesis investigates four aspects of distributed simulation: multi-threaded simulations, simulation tool coupling, distributed equation solvers and parallel optimization algorithms.

Multi-threaded simulation makes it possible to split up the workload over several processing units. This reduces simulation time, which can save both time and money during the product development cycle. The transmission line element method (TLM) is used to decouple models to independent sub-models.

Different simulation tools are suitable for different problems. Tool coupling makes it possible to use the best suited tool for simulating each part of the whole product. Models from different tools can then be coupled into one aggregated simulation model. An emerging standard for tool coupling is the Functional Mock-up Interface (FMI). It is investigated how this can be used in conjunction with TLM.

Equation-based object-oriented languages (EOOs) are becoming increasing popular. A logical approach is to let the equation solvers maintain the same structure that was used in the modelling process. Methods for achieving this using TLM and FMI are implemented and evaluated.

In addition to parallel simulations, it is also possible to use parallel optimization algorithms. This introduces parallelism on several levels. For this reason, an algorithm for profile-based multi-level scheduling is proposed.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2015. 118 p.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1732
National Category
Electrical Engineering, Electronic Engineering, Information Engineering Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:liu:diva-122754 (URN)10.3384/diss.diva-122754 (DOI)978-91-7685-875-2 (print) (ISBN)
Public defence
2015-12-18, ACAS, A-huset, Campus Valla, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2015-11-19 Created: 2015-11-19 Last updated: 2015-12-02Bibliographically approved

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