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Degree of parallelism

About: Degree of parallelism is a research topic. Over the lifetime, 1515 publications have been published within this topic receiving 25546 citations.


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Dissertation
01 Jan 2009
TL;DR: This thesis presents a novel evolutionary optimisation algorithm that can improve the quality of solutions in simulation-based optimisation and uses a Pareto approach in which the set of best trade-off solutions is searched for and presented to the user.
Abstract: This thesis presents a novel evolutionary optimisation algorithm that can improve the quality of solutions in simulation-based optimisation.Simulation-based optimisation is the process of finding optimal parameter settings without explicitly examining each possible configuration of settings. An optimisation algorithm generates potential configurations and sends these to the simulation,which acts as an evaluation function. The evaluation results are used to refine the optimisation such that it eventually returns a high-quality solution. The algorithm described in this thesis integrates multi-objective optimisation, parallelism, surrogate usage, and noise handling in a unique way for dealing with simulation-based optimisation problems inccurred by these characteristics.In order to handle multiple, conflicting optimisation objectives, the algorithm uses a Pareto approach in which the set of best trade-off solutions is searched for and presented to the user. The algorithm supports a high degree of parallelism by adopting an asynchronous master-slave parallelisation model in combination with an incremental population refinement strategy. A surrogate evaluation function is adopted in the algorithmto quickly identify promising candidate solutions and filter out poor ones. A novel technique based on inheritance is used to compensate for the uncertainties associated with the approximative surrogate evaluations. Furthermore, a novel technique for multi-objective problems that effectively reduces noise by adopting a dynamic procedure in resampling solutions is used to tackle the problem of real-world unpredictability (noise).The proposed algorithm is evaluated on benchmark problems and two complex real-world problems of manufacturing optimisation. The first real-world problem concerns the optimisation of a production cell at Volvo Aero, while the second one concerns the optimisation of a camshaft machining line at Volvo Cars Engine. The results from the optimisations show that the algorithm finds better solutions for all the problems considered than existing, similar algorithms. The new techniques for dealing with surrogate imprecision and noise used in the algorithm are identified as key reasons for the good performance.

17 citations

Proceedings Article
30 Mar 2009
TL;DR: This framework exploit the fact that randomized algorithms are available for many commonly used kernels, and that the use of parallelism can achieve very low expected execution times with high probability for these algorithms, to capture the responsiveness requirements of emerging applications as they pertain to expressed realism.
Abstract: With the advent of multi-cores and many-cores, traditional techniques that seek only to improve FLOPS of performance or the degree of parallelism have hit a roadblock with regards to providing even greater performance In order to surmount this roadblock, techniques should more directly address the underlying design objectives of an application Specific implementations and algorithmic choices in applications are intended to achieve the underlying realism objectives in the programmer's mind We identify two specific aspects of this realism that traditional programming and parallelization approaches do not capture and exploit to utilize the growing number of cores The first aspect is that the goal of minimizing program execution time can be satisfactorily met if the program execution time is low with sufficiently high probability We exploit the fact that randomized algorithms are available for many commonly used kernels, and that the use of parallelism can achieve very low expected execution times with high probability for these algorithms This can provide speedups to parts of the application that were hitherto deemed sequential and ignored for extracting performance via multi-cores The second aspect of realism that we exploit is that important classes of emerging applications, like gaming and interactive visualization, have user-interactivity and responsiveness requirements that are as important as raw performance Their design goal is to maximize the functionality expressed, while maintaining a high and smooth frame-rate Therefore, the primary objective for these applications is not to run a fixed computation as fast as possible, but rather to scale the application semantics up or down depending on the resources available Our framework intends to capture the responsiveness requirements of these applications as they pertain to expressed realism and automatically scale the application semantics expressed on every architecture, including very resource-rich many-cores

17 citations

Journal ArticleDOI
TL;DR: A new parallel solver for the volumetric integral equations of electrodynamics is presented, based on the Galerkin method, which ensures convergent numerical solution and exhibits perfect scalability on different hardware platforms.
Abstract: A new parallel solver for the volumetric integral equations (IE) of electrodynamics is presented. The solver is based on the Galerkin method, which ensures convergent numerical solution. The main features include: (i) memory usage eight times lower compared with analogous IE-based algorithms, without additional restrictions on the background media; (ii) accurate and stable method to compute matrix coefficients corresponding to the IE; and (iii) high degree of parallelism. The solver’s computational efficiency is demonstrated on a problem of magnetotelluric sounding of media with large conductivity contrast, revealing good agreement with results obtained using the second-order finite-element method. Due to the effective approach to parallelization and distributed data storage, the program exhibits perfect scalability on different hardware platforms.

17 citations

01 Nov 1994
TL;DR: A framework for bandwidth reduction and tridiagonalization algorithms for symmetric banded matrices is developed, which leads to algorithms that require fewer floating-point operations, allow for space-time tradeoffs, enable the use of block orthogonal transformations, and increase the degree of parallelism inherent in the algorithm.
Abstract: This paper develops a framework for bandwidth reduction and tridiagonalization algorithms for symmetric banded matrices. The algorithm family includes the algorithms by Rutishauser and Schwarz, which underlie the EISPACK and LAPACK implementations, and the algorithm recently proposed by Lang. The framework leads to algorithms that require fewer floating-point operations, allow for space-time tradeoffs, enable the use of block orthogonal transformations, and increase the degree of parallelism inherent in the algorithm.

17 citations

Journal ArticleDOI
TL;DR: Based on a novel self-assembly platform consisting of self-propulsive centimetre-sized modules capable of aggregation on the surface of water, the effect of stochasticity and morphology (shape) on the yield of targeted formations in self- assembly processes is studied.
Abstract: The decay in structure size of manufacturing products has yielded new demands on spontaneous composition methods. The key for the realization of small-sized robots lies in how to achieve the efficient assembly sequence in a bottom-up manner, where most of the parts have only limited or no computational i.e. deliberative abilities. In this paper, based on a novel self-assembly platform consisting of self-propulsive centimetre-sized modules capable of aggregation on the surface of water, we study the effect of stochasticity and morphology shape on the yield of targeted formations in self-assembly processes. Specifically, we focus on a unique phenomenon: that a number of modules instantly compose a target product without forming intermediate subassemblies, some of which constitute undesired geometrical formations termed one-shot aggregation. Together with a focus on the role that the morphology of the modules plays, we validate the effect of one-shot aggregation with a kinetic rate mathematical model. Moreover, we examined the degree of parallelism of the assembly process, which is an essential factor in self-assembly, but is not systematically taken into account by existing frameworks.

17 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20221
202147
202048
201952
201870
201775