Acceleration of three-dimensional Tokamak magnetohydrodynamical code with graphics processing unit and OpenACC heterogeneous parallel programming

Zhang, Haowei; Zhu, Jia; W., Z.; Kan, Guangyuan; Wang, X.; Zhang, W.

doi:10.1080/10618562.2019.1683167

Cited by 21 publications

(18 citation statements)

References 33 publications

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“…( 1). Apart from the Naiver-Stokes equations, MHD equations contain the Lorentz force in the momentum equation, Faraday's law, generalized Ohm's law, and Ampere's law neglecting displacement current [34].…”

Section: Governing Equationsmentioning

confidence: 99%

A fully implicit parallel solver for MHD instabilities in a tokamak

Yao

Jiang

et al. 2022

Preprint

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Aiming at the long-term and high-precision simulation of the magnetohydrodynamic (MHD) instabilities in the tokamak model, we developed a parallelized solver based on a fully implicit difference scheme. A 4th-order precision difference scheme and the Newton-Krylov method are employed in the proposed solver for both the flow and the electromagnetic field. To achieve high parallel efficiency, we adopt a strategy based on the spatial domain decomposition to partition the large Jacobian matrices in the iteration, and a buffer area based on the grid density is utilized to minimize the memory and time consumption. The accuracy of the methodology is verified, and the numerical results are validated by comparison with recognized results. The numerical results of the tearing mode instability in the tokamak model have demonstrated the precision and reliability of the algorithm, and the high parallel efficiency has been proven by the scalability test on the platform with up to 1280 threads, showing significant potential in the large-scale simulation of MHD problems.

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Section: Governing Equationsmentioning

confidence: 99%

A fully implicit parallel solver for MHD instabilities in a tokamak

Yao

Jiang

et al. 2022

Preprint

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“…The cut-cell method [51] is used to deal with the outer boundary of the poloidal section since the physical boundary is not located at the grid points with the cylindrical coordinate system (R, ϕ, Z). Additionally, an OPENACC-MPI heterogeneous parallel scheme in graphics processing unit is used in CLT, which has greatly accelerated the simulation speed [52].…”

Section: Simulation Modelmentioning

confidence: 99%

Numerical study on nonlinear double tearing mode in ITER

Tang

et al. 2021

Nucl. Fusion

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The nonlinear dynamics of the m/n = 2/1 double tearing mode (DTM) in ITER are systematically studied using the three-dimensional toroidal magnetohydrodynamic code, CLT. We carefully investigate the effects of the radial locations and magnetic shear strengths of the inner and outer rational surfaces r 1, r 2, s 1 and s 2, as well as the safety factor at the magnetic axis q 0 on DTM. It is found that the explosive burst takes place only with the moderate separation of the two rational surfaces or the stronger magnetic shear strength in which the strong interaction of magnetic islands in the two rational surfaces happens in the early nonlinear phase of the island development. The explosive burst can result from either the direct mutual driving associated with the fast growth island in the two rational surfaces or a strong nonlinear mode–mode coupling. For a large separation and a weak shear strength of the two rational surfaces, the magnetic islands saturate without strong interaction with each other, and (w in + w out)/2 is always below the separation Δr s. For a small separation, the kinetic evolution of DTM only exhibits an oscillation with a very low level and then decreases.

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“…OpenACC, a high-level programming model based on directives like OpenMP, is supported by an initial set of three translator vendors, including Computer Assisted Program System (CAPS), Cray, and Portland Group Inc. (PGI) [13]. It works by including directives in the source code of Fortran, C, or C++, which makes it easy to use.…”

Section: Introductionmentioning

confidence: 99%

“…OpenACC is characterized by portability across devices from multiple vendors. It is also more productive than other models because it is a high-level, directive-based programming model that efficiently utilizes the GPU [1,13,14].…”

Section: Introductionmentioning

confidence: 99%

A Parallel Hybrid Testing Technique for Tri-Programming Model-Based Software Systems

Basloom¹,

Dahab²,

AL-Ghamdi³

et al. 2023

Computers, Materials &Amp; Continua

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Recently, researchers have shown increasing interest in combining more than one programming model into systems running on high performance computing systems (HPCs) to achieve exascale by applying parallelism at multiple levels. Combining different programming paradigms, such as Message Passing Interface (MPI), Open Multiple Processing (OpenMP), and Open Accelerators (OpenACC), can increase computation speed and improve performance. During the integration of multiple models, the probability of runtime errors increases, making their detection difficult, especially in the absence of testing techniques that can detect these errors. Numerous studies have been conducted to identify these errors, but no technique exists for detecting errors in three-level programming models. Despite the increasing research that integrates the three programming models, MPI, OpenMP, and OpenACC, a testing technology to detect runtime errors, such as deadlocks and race conditions, which can arise from this integration has not been developed. Therefore, this paper begins with a definition and explanation of runtime errors that result from integrating the three programming models that compilers cannot detect. For the first time, this paper presents a classification of operational errors that can result from the integration of the three models. This paper also proposes a parallel hybrid testing technique for detecting runtime errors in systems built in the C++ programming language that uses the triple programming models MPI, OpenMP, and OpenACC. This hybrid technology combines static technology and dynamic technology, given that some errors can be detected using static techniques, whereas others can be detected using dynamic technology. The hybrid technique can detect more errors because it combines two distinct technologies. The proposed static technology detects a wide range of error types in less time, whereas a portion of the potential errors that may or may not occur depending on the 4502 CMC, 2023, vol.74, no.2 operating environment are left to the dynamic technology, which completes the validation.

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Acceleration of three-dimensional Tokamak magnetohydrodynamical code with graphics processing unit and OpenACC heterogeneous parallel programming

Cited by 21 publications

References 33 publications

A fully implicit parallel solver for MHD instabilities in a tokamak

A fully implicit parallel solver for MHD instabilities in a tokamak

Numerical study on nonlinear double tearing mode in ITER

A Parallel Hybrid Testing Technique for Tri-Programming Model-Based Software Systems

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