Getting Started with OpenMP

Chandra, Rohit; Dagum, Leonardo; Kohr, Dave; McDonald, Jeff; Menon, Ramesh

doi:10.1016/b978-155860671-5/50003-7

Cited by 83 publications

(99 citation statements)

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“…Furthermore, in the continuity equation an extra 'Newton's term' is added for z ∈ [0, 0.7] in order to avoid sharp density variations close to the bottom boundary. The calculation is parallelized using a combination of the OpenMP (Chandra et al 2001) and the Message-Passing Interface (MPI) standards (Gropp et al 1999). For OHM-MPI, OpenMP is used to distribute work among cores on individual nodes, while MPI is used to pass data between nodes.…”

mentioning

confidence: 99%

Critical Decay Index at the Onset of Solar Eruptions

Zuccarello

Aulanier

Gilchrist

2015

ApJ

126

145

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Magnetic flux ropes are topological structures consisting of twisted magnetic field lines that globally wrap around an axis. The torus instability model predicts that a magnetic flux rope of major radius R undergoes an eruption when its axis reaches a location where the decay index −d(ln B ex )/d(ln R) of the ambient magnetic field B ex is larger than a critical value. In the current-wire model, the critical value depends on the thickness and time-evolution of the current channel. We use magneto-hydrodynamic (MHD) simulations to investigate if the critical value of the decay index at the onset of the eruption is affected by the magnetic flux rope's internal current profile and/or by the particular pre-eruptive photospheric dynamics. The evolution of an asymmetric, bipolar active region is driven by applying different classes of photospheric motions. We find that the critical value of the decay index at the onset of the eruption is not significantly affected by either the pre-eruptive photospheric evolution of the active region or by the resulting different magnetic flux ropes. As in the case of the current-wire model, we find that there is a 'critical range' [1.3 − 1.5], rather than a 'critical value' for the onset of the torus instability. This range is in good agreement with the predictions of the current-wire model, despite the inclusion of line-tying effects and the occurrence of tether-cutting magnetic reconnection.

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mentioning

confidence: 99%

Critical Decay Index at the Onset of Solar Eruptions

Zuccarello

Aulanier

Gilchrist

2015

ApJ

126

145

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“…Thus, we assume a shared-memory computer with processors. The parallel programming environment that allows the use of this computer is OpenMP [31]. There are multithread implementations of the basic linear algebra library BLAS [32], which can be used by higher level libraries (LAPACK [33]) to take advantage of this architecture by using multithreading techniques.…”

Section: Parallel Algorithmsmentioning

confidence: 99%

Benchmarking in Data Envelopment Analysis: An Approach Based on Genetic Algorithms and Parallel Programming

Aparicio

López-Espín

Martinez-Moreno

et al. 2014

Advances in Operations Research

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Data Envelopment Analysis (DEA) is a nonparametric technique to estimate the current level of efficiency of a set of entities. DEA also provides information on how to remove inefficiency through the determination of benchmarking information. This paper is devoted to study DEA models based on closest efficient targets, which are related to the shortest projection to the production frontier and allow inefficient firms to find the easiest way to improve their performance. Usually, these models have been solved by means of unsatisfactory methods since all of them are related in some sense to a combinatorial NP-hard problem. In this paper, the problem is approached by genetic algorithms and parallel programming. In addition, to produce reasonable solutions, a particular metaheuristic is proposed and checked through some numerical instances.

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“…The correntropy coefficient was implemented in parallel using the OpenMP framework [26]. In order to facilitate the parallelization, we organized the sequence of operations for the calculation of the correntropy coefficient.…”

Section: Parallel Implementation Of the Correntropy Coefficientmentioning

confidence: 99%

On the parallel efficiency and scalability of the correntropy coefficient for image analysis

Fontes¹,

Xavier‐de‐Souza²,

Neto³

et al. 2014

J Braz Comput Soc

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Background: Similarity measures have application in many scenarios of digital image processing. The correntropy is a robust and relatively new similarity measure that recently has been employed in various engineering applications. Despite other competitive characteristics, its computational cost is relatively high and may impose hard-to-cope time restrictions for high-dimensional applications, including image analysis and computer vision. Methods: We propose a parallelization strategy for calculating the correntropy on multi-core architectures that may turn the use of this metric viable in such applications. We provide an analysis of its parallel efficiency and scalability. Results:The simulation results were obtained on a shared memory system with 24 processing cores for input images of different dimensions. We performed simulations of various scenarios with images of different sizes. The aim was to analyze the parallel and serial fraction of the computation of the correntropy coefficient and the influence of these fractions in its speedup and efficiency. Conclusions:The results indicate that correntropy has a large potential as a metric for image analysis in the multi-core era due to its high parallel efficiency and scalability.

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Getting Started with OpenMP

Cited by 83 publications

References 0 publications

Critical Decay Index at the Onset of Solar Eruptions

Critical Decay Index at the Onset of Solar Eruptions

Benchmarking in Data Envelopment Analysis: An Approach Based on Genetic Algorithms and Parallel Programming

On the parallel efficiency and scalability of the correntropy coefficient for image analysis

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