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1

An adaptive multi-spline refinement algorithm in simulation based sailboat trajectory optimization using onboard multi-core computer systems

Dębski R.

International Journal of Applied Mathematics and Computer Science

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2016

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Vol. 26, no. 2

351--365

EN

A new dynamic programming based parallel algorithm adapted to on-board heterogeneous computers for simulation based trajectory optimization is studied in the context of “high-performance sailing”. The algorithm uses a new discrete space of continuously differentiable functions called the multi-splines as its search space representation. A basic version of the algorithm is presented in detail (pseudo-code, time and space complexity, search space auto-adaptation properties). Possible extensions of the basic algorithm are also described. The presented experimental results show that contemporary heterogeneous on-board computers can be effectively used for solving simulation based trajectory optimization problems. These computers can be considered micro high performance computing (HPC) platforms—they offer high performance while remaining energy and cost efficient. The simulation based approach can potentially give highly accurate results since the mathematical model that the simulator is built upon may be as complex as required. The approach described is applicable to many trajectory optimization problems due to its black-box represented performance measure and use of OpenCL.

2

Simulation-based sailboat trajectory optimization using on-board heterogeneous computers

Dębski R.

Computer Science

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2016

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Vol. 17 (4)

461--481

EN

A dynamic programming-based algorithm adapted to on-board heterogeneous computers for simulation-based trajectory optimization was studied in the context of high-performance sailing. The algorithm can efficiently utilize all OpenCL-capable devices, starting the computation (if necessary, in single precision) on a GPU and finalizing it (if necessary, in double-precision) with the use of a CPU. The serial and parallel versions of the algorithm are presented in detail. Possible extensions of the basic algorithm are also described. The experimental results show that contemporary heterogeneous on-board/mobile computers can be treated as micro HPC platforms. They offer high performance (the OpenCL-capable GPU was found to accelerate the optimization routine 41 fold) while remaining energy and cost efficient. The simulation-based approach has the potential to give very accurate results, as the mathematical model upon which the simulator is based may be as complex as required. The black-box represented performance measure and the use of OpenCL make the presented approach applicable to many trajectory optimization problems.

3

Analysis of Application of Distributed Multi-Node, Multi-GPU Heterogeneous System for Acceleration of Image Reconstruction in Electrical Capacitance Tomography

Majchrowicz M., Kapusta P., Jackowska-Strumiłło L., Sankowski D.

Image Processing & Communications

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2015

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Vol. 20, no. 3

5--14

EN

3D ECT provides a lot of challenging computational issues that have been reported in the past by many researchers. Image reconstruction using deterministic methods requires execution of many basic operations of linear algebra, such as matrix transposition, multiplication, addition and subtraction. In order to reach real-time reconstruction a 3D ECT computational subsystem has to be able to transform capacitance data into image in fractions of seconds. By assuming, that many of the computations can be performed in parallel using modern, fast graphics processor and by altering the algorithms time to achieve high quality image reconstruction will be shortened significantly. The research conducted while analysing ECT algorithms has also shown that, although dynamic development of GPU computational capabilities and its recent application for image reconstruction in ECT has significantly improved calculations time, in modern systems a single GPU is not enough to perform many tasks. Distributed Multi-GPU solutions can reduce reconstruction time to only a fraction of what was possible on pure CPU systems. Nevertheless performed tests clearly illustrate the need for developing a new distributed platform, which would be able to fully utilize the potential of the hardware. It has to take into account specific nature of computations in Multi-GPU systems.

4

On application of heterogeneous hardware architectures based on advanced RISC machines to fem calculations

Bzowski K., Rauch Ł.

Computer Methods in Materials Science

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2015

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Vol. 15, No.3

435--440

EN

Advanced RISC Machine (ARM) hardware architectures are nowadays one of the most popular solutions among processors widelypresent in mobile and embedded systems. Due to relatively low power consumption and high multithreaded capabilities they can be found in more than 75% 32-bits devices (Frenzel Jr, 2010). Modern ARM processors also contain integrated high efficiency graphics units like Mali T6xx which made them particularly useful for growing market of mobile devices. Mali processors support OpenCL standard which made them valuable for wide range of scientific computing, where processing power is as much important as power consumption. Presented paper contains proof of concept of Finite Element Method (FEM) software capable to compute transient heat transfer analysis and implemented for ARM architecture. Exemplary implementation using OpenCL was prepared. Efficiency data as well as comparison between modern GPGPU, accelerators and ARM devices are included in the paper.

PL

Architektura Advanced RISC Machinę (ARM) jest obecnie jedną z najbardziej popularnych rozwiązań wśród procesorów mobilnych i systemów wbudowanych. W związku ze znacznie mniejszym zużyciem energii elektrycznej i wysoką wielowątkowością znalazły one zastosowanie w ponad 75% obecnie stosowanych systemów 32-bitowych (Frenzel Jr, 2010). Nowoczesne procesory ARM zawierają często zintegrowane jednostki graficzne wysokiej wydajności, takie jak Mali T6xx, co sprawia że stały się one szczególnie użyteczne dla dynamicznie rozwijającego się rynku urządzeń mobilnych. Procesory z rodziny Mali T6xx wspierają standard OpenCL, co powoduje, że mogą one również zostać wykorzystane w szerokiej gamie obliczeń naukowych, w których moc obliczeniowa jest tak samo istotna jak oszczędność energii. W artykule przedstawiono koncepcję oprogramowania wykorzystującego metodę elementów skończonych do obliczeń niestacjonarnych przepływów ciepła z wykorzystaniem architektury obliczeniowej ARM. Przedstawiono przykładową implementację z wykorzystaniem technologii OpenCL, jak również wykonano testy porównawcze z nowoczesnymi architekturami GPGPU oraz analizy energetyczne.

5

High-performance simulation-based algorithms for an alpine ski racer’s trajectory optimization in heterogeneous computer systems

Dębski R.

International Journal of Applied Mathematics and Computer Science

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2014

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Vol. 24, no. 3

551--566

EN

Effective, simulation-based trajectory optimization algorithms adapted to heterogeneous computers are studied with reference to the problem taken from alpine ski racing (the presented solution is probably the most general one published so far). The key idea behind these algorithms is to use a grid-based discretization scheme to transform the continuous optimization problem into a search problem over a specially constructed finite graph, and then to apply dynamic programming to find an approximation of the global solution. In the analyzed example it is the minimum-time ski line, represented as a piecewise-linear function (a method of elimination of unfeasible solutions is proposed). Serial and parallel versions of the basic optimization algorithm are presented in detail (pseudo-code, time and memory complexity). Possible extensions of the basic algorithm are also described. The implementation of these algorithms is based on OpenCL. The included experimental results show that contemporary heterogeneous computers can be treated as μ-HPC platforms—they offer high performance (the best speedup was equal to 128) while remaining energy and cost efficient (which is crucial in embedded systems, e.g., trajectory planners of autonomous robots). The presented algorithms can be applied to many trajectory optimization problems, including those having a black-box represented performance measure.

6

Creation and application of heterogeneous grid environment for seismic modeling

Strzelczyk J., Danek T.

Geoinformatica Polonica

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2009

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T. 9

35--41

EN

Grid computing is a simultaneous application of several computers to one, single, computationally intensive problem. A computer grid can be created from special, dedicated hardware. but ais o unused CPU cycles of available desktop machines can be exploited. This article report s on a successful effort of creating a heterogeneous grid infrastructure. The installation consisted of two Blade servers and one PC machine that were available at the time. Heterogeneity was present on both levels: hardware platform and operating system. Blade machines ran Linux Fedora Core, while PC ran Windows 2000 SP4. Using only free grid software, the authors created working infrastructure and used it in seismic modeling ca1culations.

PL

Termin grid computing oznacza jednoczesne wykorzystanie kilku komputerów do rozwiązywania jednego, złożonego problemu obliczeniowego. Komputerowy grid może zostać stworzony ze specjalnych urządzeń dedykowanych, przeznaczonych do tego celu, bądź także z nieużywanych procesorów dostępnych w biurowych komputerach Pc. W tym artykule opisano udaną próbę stworzenia heterogenicznej infrastruktury gridowej. System składał się z dwóch serwerów typu IBM Blade oraz z jednej maszyny PC, która była aktualnie dostępna. Heterogeniczność była obecna na obu poziomach: platformy sprzętowej oraz systemu operacyjnego. Na maszynach typu IBM Blade zainstalowany był system Linux Fedora Core, a komputer PC działał pod kontrolą systemu Windows 2000 SP4. Używając jedynie darmowego oprogramowania gridowego, autorzy stworzyli działającą infrastrukturę i użyli jej w procesie modelowania sejsmicznego pola falowego.