<p> A highly parallel computing system capable of computing transcendental functions, matrix operations and iterative calculations has been devised and a typical cell has been implemented. The system consists of an array of cells, a control unit, a PDP-11 computer and an interface unit. The array uses modified SOLOMON type of communication between cells. Each cell consists of 15 words and arithmetic hardware. Arithmetic and logic operations, on words or bytes, may be performed serially between pairs of these words. Division and floating-point arithmetic are under software control. Parallel algorithms have been developed. A set of instructions and mnemonics permits a practical use of the system. The possibility of using the array as an associative-memory processor is also considered. The system has been tested by using the software package prepared. Although only one cell has actually been constructed a complete array has been simulated on a PDP-11 computer.</p> / Thesis / Master of Engineering (MEngr)

Parallel and distributed environments are used to solve large scientific and engineering problems that often are irregular and data parallel. However, performance of many parallel applications is affected by computation overheads, communication time and load imbalance. Among these factors, load imbalance is caused by the irregular nature of the problem, its algorithm, the difference in processor characteristics, and runtime loads. A number of applications achieve load balancing by one-time assignment of task. However, a number of applications have workloads that are unpredictable, and vary over the course of their execution. For such type of applications, load balancing is achieved by dynamic assignment of tasks at runtime. A large group of scientific applications has parallel loops as major source of concurrency. However, due to the irregular execution times of the loops, it is difficult to achieve optimal performance without dynamic load balancing. There are number of dynamic load balancing tools and libraries have been developed for different kind of applications. However these libraries fail to address all three degradation factors i.e. problem, algorithmic, and systemic. In this thesis a dynamic load balancing library called LB_Migrate is presented which addresses the degradation factors in application with parallel loops. The library provides a range of dynamic scheduling techniques and data migration strategies to achieve effective load balancing. It is designed to be independent of the host application data structure hence providing the flexibility to be used with different applications. The analysis of the experimental results using LB_Migrate with different applications indicates consistent performance improvement, and low overhead cost by the use of the library.

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With advanced subsonic transports and military aircraft operating in the transonic regime, it is becoming important to determine the effects of the coupling between aerodynamic loads and elastic forces. Since aeroelastic effects can contribute significantly to the design of these aircraft, there is a strong need in the aerospace industry to predict these aero-structure interactions computationally. To perform static aeroelastic analysis in the transonic regime, high fidelity computational fluid dynamics (CFD) analysis tools must be used in conjunction with high fidelity computational structural dynamics (CSD)analysis tools due to the nonlinear behavior of the aerodynamics in the transonic regime. There is also a need to be able to use a wide variety of CFD and CSD tools to predict these aeroelastic effects in the transonic regime. Because source codes are not always available, it is necessary to couple the CFD and CSD codes without alteration of the source codes. In this study, an aeroelastic coupling procedure is developed which will perform static aeroelastic analysis using any CFD and CSD code with little code integration. The aeroelastic coupling procedure is demonstrated on an F/A-18 Stabilator using NASTD (an in-house McDonnell Douglas CFD code)and NASTRAN. In addition, the Aeroelastic Research Wing (ARW-2) is used for demonstration of the aeroelastic coupling procedure by using ENSAERO (NASA Ames Research Center CFD code) and a finite element wing-box code (developed as a part of this research). The results obtained from the present study are compared with those available from an experimental study conducted at NASA Langley Research Center and a study conducted at NASA Ames Research Center using ENSAERO and modal superposition. The results compare well with experimental data. In addition, parallel computing power is used to investigate parallel static aeroelastic analysis because obtaining an aeroelastic solution using CFD/CSD methods is computationally intensive. A parallel finite element wing-box code is developed and coupled with an existing parallel Euler code to perform static aeroelastic analysis. A typical wing-body configuration is used to investigate the applicability of parallel computing to this analysis. Performance of the parallel aeroelastic analysis is shown to be poor; however with advances being made in the arena of parallel computing, there is definitely a need to continue research in this area. / Ph. D.

Crowd simulation is used for many applications including (but not limited to) videogames, building planning, training simulators, and various virtual environment applications. Particularly, crowd simulation is most useful for when real life practices wouldn't be practical such as repetitively evacuating a building, testing the crowd flow for various building blue prints, placing law enforcers in actual crowd suppression circumstances, etc. In our work, we approach the fidelity to scalability problem of crowd simulation from two angles, a programmability angle, and a scalability angle, by creating new methodology building off of a struct of arrays approach and transforming it into an Object Oriented Struct of Arrays approach. While the design pattern itself is applied to crowd simulation in our work, the application of crowd simulation exemplifies the variety of applications for which the design pattern can be used. / Master of Science

Arguably, from the programmer's perspective, the programming model is the most important characteristic of any computer system. Perhaps this explains why, after many decades of research, architects and programmers alike continue to debate the appropriate programming model for parallel computers. Though thousands of programming models have been developed, standards such as PVM and MPI have made send-and-receive based message-passing the most popular programming model for distributed memory architectures. This thesis explores modifying the Single-Chip Message-Passing (SCMP) architecture to more efficiently support send-and-receive based message-passing. The proposed system is compared, for performance and programmability, to the active messaging programming model currently used by SCMP. SCMP offers a unique platform for send-and-receive based message-passing. The SCMP design incorporates multiple multi-threaded processors, memory, and a network onto a single chip. This integration reduces the penalties of thread switching, memory access, and inter-process communication typically seen on more traditional distributed memory parallel machines. The mechanisms proposed in this thesis to support send-and-receive based message-passing on SCMP attempt to preserve and exploit these features as much as possible. / Master of Science

Nous nous intéressons à l'utilisation de la technologie manycore des cartes graphiques dans le cadre de la Chimie théorique. Nous soutenons la nécessité pour ce domaine d'être capable de tirer profit de cette technologie. Nous montrons la faisabilité et les limites de l'utilisation de cartes graphiques en Chimie théorique par le portage sur GPU de deux méthodes de calcul en modélisation moléculaire. Ces deux méthodes n’intégrerons ultérieurement au programme de docking moléculaire AlgoGen. L'accélération et la performance énergétique ont été examinées au cours de ce travail.Le premier programme NCIplot implémente la méthodologie NCI qui permet de détecter et de caractériser les interactions non-covalentes dans un système chimique. L'approche NCI se révèle être idéale pour l'utilisation de cartes graphiques comme notre analyse et nos résultats le montrent. Le meilleur portage que nous avons obtenu, a permis de constater des facteurs d'accélération allant jusqu'à 100 fois plus vite par rapport au programme NCIplot. Nous diffusons actuellement librement notre portage GPU : cuNCI.Le second travail de portage sur GPU se base sur GAMESS qui est un logiciel complexe de portée internationale implémentant de nombreuses méthodes quantiques. Nous nous sommes intéressés à la méthode combinée DFTB/FMO/PCM pour le calcul quantique de l'énergie potentielle d'un complexe. Nous sommes intervenus dans la partie du programme calculant l'effet du solvant. Ce cas s'avère moins favorable à l'utilisation de cartes graphiques, cependant nous avons su obtenir une accélération. / In this research work we are interested in the use of the manycore technology of graphics cards in the framework of approaches coming from the field of Theoretical Chemistry. We support the need for Theoretical Chemistry to be able to take advantage of the use of graphics cards. We show the feasibility as well as the limits of the use of graphics cards in the framework of the theoretical chemistry through two usage of GPU on different approaches.We first base our research work on the GPU implementation of the NCIplot program. The NCIplot program has been distributed since 2011 by Julia CONTRERAS-GARCIA implementing the NCI methodology published in 2010. The NCI approach is proving to be an ideal candidate for the use of graphics cards as demonstrated by our analysis of the NCIplot program, as well as the performance achieved by our GPU implementations. Our best implementation (VHY) shows an acceleration factors up to 100 times faster than the NCIplot program. We are currently freely distributing this implementation in the cuNCI program.The second GPU accelerated work is based on the software GAMESS-US, a free competitor of GAUSSIAN. GAMESS is an international software that implements many quantum methods. We were interested in the simultaneous use of DTFB, FMO and PCM methods. The frame is less favorable to the use of graphics cards however we have been able to accelerate the part carried by two K20X graphics cards.

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