Este trabalho tem como objetivo desenvolver e empregar técnicas e estruturas de dados agrupadas visando paralelizar os métodos do subespaço de Krylov, fazendo-se uso de diversas ferramentas e abordagens. A partir dos resultados é feita uma análise comparativa de desemvpenho destas ferramentas e abordagens. As paralelizações aqui desenvolvidas foram projetadas para serem executadas em um arquitetura formada por um agregado de máquinas indepentes e multiprocessadas (Cluster), ou seja , são considerados o paralelismo e intra-nodos. Para auxiliar a programação paralela em clusters foram, e estão sendo, desenvolvidas diferentes ferramentas (bibliotecas) que visam a exploração dos dois níveis de paralelismo existentes neste tipo de arquitetura. Neste trabalho emprega-se diferentes bibliotecas de troca de mensagens e de criação de threads para a exploração do paralelismo inter-nodos e intra-nodos. As bibliotecas adotadas são o DECK e o MPICH e a Pthread. Um dos itens a serem analisados nestes trabalho é acomparação do desempenho obtido com essas bibliotecas.O outro item é a análise da influência no desemepnho quando quando tulizadas múltiplas threads no paralelismo em clusters multiprocessados. Os métodos paralelizados nesse trabalho são o Gradiente Conjugação (GC) e o Resíduo Mínmo Generalizado (GMRES), quepodem ser adotados, respectivamente, para solução de sistemas de equações lineares sintéticos positivos e definidos e não simétricas. Tais sistemas surgem da discretização, por exemplo, dos modelos da hidrodinâmica e do transporte de massa que estão sendo desenvolvidos no GMCPAD. A utilização desses métodos é justificada pelo fato de serem métodos iterativos, o que os torna adequados à solução de sistemas de equações esparsas e de grande porte. Na solução desses sistemas através desses métodos iterativos paralelizados faz-se necessário o particionamento do domínio do problema, o qual deve ser feito visando um bom balanceamento de carga e minimização das fronteiras entre os sub-domínios. A estrutura de dados desenvolvida para os métodos paralelizados nesse trabalho permite que eles sejam adotados para solução de sistemas de equações gerados a partir de qualquer tipo de particionamento, pois o formato de armazenamento de dados adotado supre qualquer tipo de dependência de dados. Além disso, nesse trabalho são adotadas duas estratégias de ordenação para as comunicações, estratégias essas que podem ser importantes quando se considera a portabilidade das paralelizações para máquinas interligadas por redes de interconexão com buffer de tamanho insuficiente para evitar a ocorrência de dealock. Os resultados obtidos nessa dissertação contribuem nos trabalhos do GMCPAD, pois as paralelizações são adotadas em aplicações que estão sendo desenvolvidas no grupo.

Este trabalho tem como objetivo desenvolver e empregar técnicas e estruturas de dados agrupadas visando paralelizar os métodos do subespaço de Krylov, fazendo-se uso de diversas ferramentas e abordagens. A partir dos resultados é feita uma análise comparativa de desemvpenho destas ferramentas e abordagens. As paralelizações aqui desenvolvidas foram projetadas para serem executadas em um arquitetura formada por um agregado de máquinas indepentes e multiprocessadas (Cluster), ou seja , são considerados o paralelismo e intra-nodos. Para auxiliar a programação paralela em clusters foram, e estão sendo, desenvolvidas diferentes ferramentas (bibliotecas) que visam a exploração dos dois níveis de paralelismo existentes neste tipo de arquitetura. Neste trabalho emprega-se diferentes bibliotecas de troca de mensagens e de criação de threads para a exploração do paralelismo inter-nodos e intra-nodos. As bibliotecas adotadas são o DECK e o MPICH e a Pthread. Um dos itens a serem analisados nestes trabalho é acomparação do desempenho obtido com essas bibliotecas.O outro item é a análise da influência no desemepnho quando quando tulizadas múltiplas threads no paralelismo em clusters multiprocessados. Os métodos paralelizados nesse trabalho são o Gradiente Conjugação (GC) e o Resíduo Mínmo Generalizado (GMRES), quepodem ser adotados, respectivamente, para solução de sistemas de equações lineares sintéticos positivos e definidos e não simétricas. Tais sistemas surgem da discretização, por exemplo, dos modelos da hidrodinâmica e do transporte de massa que estão sendo desenvolvidos no GMCPAD. A utilização desses métodos é justificada pelo fato de serem métodos iterativos, o que os torna adequados à solução de sistemas de equações esparsas e de grande porte. Na solução desses sistemas através desses métodos iterativos paralelizados faz-se necessário o particionamento do domínio do problema, o qual deve ser feito visando um bom balanceamento de carga e minimização das fronteiras entre os sub-domínios. A estrutura de dados desenvolvida para os métodos paralelizados nesse trabalho permite que eles sejam adotados para solução de sistemas de equações gerados a partir de qualquer tipo de particionamento, pois o formato de armazenamento de dados adotado supre qualquer tipo de dependência de dados. Além disso, nesse trabalho são adotadas duas estratégias de ordenação para as comunicações, estratégias essas que podem ser importantes quando se considera a portabilidade das paralelizações para máquinas interligadas por redes de interconexão com buffer de tamanho insuficiente para evitar a ocorrência de dealock. Os resultados obtidos nessa dissertação contribuem nos trabalhos do GMCPAD, pois as paralelizações são adotadas em aplicações que estão sendo desenvolvidas no grupo.

This thesis presents the parallel version of Coliseum, the Air Force Research Laboratory plasma simulation framework. The parallel code was designed to run large simulations on the world fastest supercomputers as well as home mode clusters. Plasma simulations are extremely computationally intensive as they require tracking millions of particles and solving field equations over large domains. This new parallel version will allow Coliseum to run simulations of spacecraft-plasma interactions in domain large enough to reproduce space conditions. The parallel code ran on two of the world fastest supercomputers, the NASA JPL Cosmos supercomputer ranked 37th on the TOP500 list and Virginia Tech's System X, ranked 7th. DRACO, the Virginia Tech PIC module to Coliseum, was modified with parallel algorithms to create a full parallel PIC code. A parallel solver was added to DRACO. It uses a Gauss-Seidel method with SOR acceleration on a Red-Black checkerboard scheme. Timing results were obtained on JPL Cosmos supercomputer to determine the efficiency of the parallel code. Although the communication overhead limits the code's parallel efficiency, the speed up obtained greatly decreases the time required to run the simulations. A speed up of 51 was reached on 128 processors. The parallel code was also used to simulate the plume expansion of an ion thruster array composed of three NSTAR thrusters. Results showed that the multiple beams merge to form a single plume similar to the plume created by a single ion thruster. / Master of Science

MPI I/O replay (MPIOR) is an I/O performance modeling and prediction tool used to trace and replay a parallel application to determine application performance under a new I/O sub system. The trace collector deduces synchronization inter-dependencies between nodes and I/O demands placed by each node on the storage subsystem. It uses a novel runtime graph traversal technique to filter and log only those MPI calls that affect I/O, thus substantially reducing both the number of runs and the size of the trace file. Unlike other such tools, MPIOR collects a valid trace in a single run and it does not rely on node sampling or I/O sampling. MPIOR's post processing engine analyzes the trace files and sets up the re-player. Due to minimal overhead for trace collection, MPIOR can be used during production runs rather than just as a debugging tool. The re-player mimics the behavior of the application across a variety of storage systems by mapping multiple processes to multiple threads running on a single node. We show average replay error for parallel applications is below 30%. / Master of Science

No description available.

No description available.

This paper describes the basic concepts of our solution to improve the performance of Ethernet Communication on a Linux Cluster environment by introducing Reliable Low Latency Ethernet Sockets. We show that about 25% of the socket latency can be saved by using our simplified protocol. Especially, we put emphasis on demonstrating that this performance benefit is able to speed up the MPI level communication. Therefore we have developed a new BTL component for Open MPI, an open source MPI-2 implementation which offers with its Modular Component Architecture a nearly ideal environment to implement our changes. Microbenchmarks of MPI collective and Point-to-Point operations were performed. We see a performance improvement of 8% to 16% for LU and SP implementations of the NAS parallel benchmark suite which spends a significant amount of time in the MPI. Practical application tests with Abinit, an electronic structure calculation program, show that the runtime of be nearly halved on a 4 node system. Thus we show evidence that our new Ethernet communication protocol is able to increase the speedup of parallel applications considerably.

This paper describes the basic concepts of our solution to improve the performance of Ethernet Communication on a Linux Cluster environment by introducing Reliable Low Latency Ethernet Sockets. We show that about 25% of the socket latency can be saved by using our simplified protocol. Especially, we put emphasis on demonstrating that this performance benefit is able to speed up the MPI level communication. Therefore we have developed a new BTL component for Open MPI, an open source MPI-2 implementation which offers with its Modular Component Architecture a nearly ideal environment to implement our changes. Microbenchmarks of MPI collective and Point-to-Point operations were performed. We see a performance improvement of 8% to 16% for LU and SP implementations of the NAS parallel benchmark suite which spends a significant amount of time in the MPI. Practical application tests with Abinit, an electronic structure calculation program, show that the runtime of be nearly halved on a 4 node system. Thus we show evidence that our new Ethernet communication protocol is able to increase the speedup of parallel applications considerably.

Understanding the role that tourism play in poverty alleviation globally has been a research focus of many studies in different countries. For an extended period the trickle down method of wealth distribution, where it was believed that riches find its way down the value chain to the poor in terms of taxes spent on welfare, infrastructure, grants etc., was globally accepted. In recent years though, focus on tourism as tool for increasing economic growth and poverty alleviation has been placed at the centre. It is true that in many cases tourism made a difference in the lives of the poor but it is also true that in many instances this is not the case. This dissertation analysed the perceived contribution made by tourism to poverty alleviation in Mozambique in general, and Praia de Bilene and Macanetta peninsula in particular. These are pre-eminently tourist destinations and ideally suited for a study of this nature. The primary goal of this dissertation was to determine the contribution of tourism to poverty alleviation in Mozambique by assessing Praia Bilene and Macanetta peninsula. The first objective was to describe and understand the link between tourism and poverty. It was found that the traditional definition of poverty no longer applies to most situations. That it is better to view poverty as a lack of access instead of money, access to natural resources, bureaucratic processes, capital markets and entrepreneurship. The review analysed different research methods, looking in depth at the livelihood analysis, ST~EP and MPI. The three pathways namely direct, indirect and induced levels on how tourism affects the poor were also explored. The most challenging area has to be the quantifying of tourism impacts on communities and local livelihoods. Concluding that the measurement of tourism impacts on poverty alleviation is an intricate debate and not easily accomplished. The second objective was to analyse the current status of the tourism industry in Mozambique. With 48% of sub-Sahara living in poverty, the picture in Mozambique is even drearier, with 54% living under the poverty line and 81% living under the $2 poverty line in the country (OPHI, 2013:1), confirming that it is one of the world’s poorest countries. Mozambique’s profile was analysed on its poverty status, tourism development, growth and the tourism impacts on the local communities of Bilene and Macanetta. It was found that several tourism opportunities are scooped up by foreigners and that this causes a major leakage of resources from regions where poverty alleviation by tourism is attempted. At a 7% GDP growth rate Mozambique is making very good progress, but due to being so poor and behind it is not reducing the poverty fast enough. The third objective was to determine the perceptions of two Mozambique communities on tourism impacts and the impact of tourism on their poverty status by incorporating the multi-dimensional poverty index. A perception analysis was done by means of a structured questionnaire presented to random residents from all walks of life at the two specific locations mentioned. The correlation between MPI and perceptions of the impacts of tourism shown that resident’s perceptions of tourism do not influence their deprivation scores negative or positive. It was however determined in an open question that an overwhelming 4 out of 5 people felt that tourism did contribute to poverty alleviation. The perceptions and reality therefore differ. The last objective was to draw conclusions and make recommendations with regard to the contribution of tourism to poverty alleviation in selected Mozambican communities. Conclusions were drawn as to the effectiveness of tourism as a strategic method in the onslaught against poverty in the selected communities. Amongst these conclusions was the fact that poverty seems to be an increasingly complex phenomenon. Due to the difficulty in defining poverty, a wide variety of research methods need to be used to assess the situation. No single approach to impact valuation of tourism on poverty can present all the answers. Concluding in this analysis into poverty and tourism’s relationship it was determined that not only did the factual data show that tourism did not alleviate poverty at these locations but that the population, in stark contrast to empirical proof, determined in their own mind that they perceived a definite improvement due to tourism. Thus residents do not necessarily receive personal benefits from tourism but they are positive towards the tourism industry. This should be utilised by creating opportunities for higher levels of participation in the industry as well as generating more tangible, positive affects for the local population in Mozambique. / MA (Tourism Management), North-West University, Potchefstroom Campus, 2014

Understanding the role that tourism play in poverty alleviation globally has been a research focus of many studies in different countries. For an extended period the trickle down method of wealth distribution, where it was believed that riches find its way down the value chain to the poor in terms of taxes spent on welfare, infrastructure, grants etc., was globally accepted. In recent years though, focus on tourism as tool for increasing economic growth and poverty alleviation has been placed at the centre. It is true that in many cases tourism made a difference in the lives of the poor but it is also true that in many instances this is not the case. This dissertation analysed the perceived contribution made by tourism to poverty alleviation in Mozambique in general, and Praia de Bilene and Macanetta peninsula in particular. These are pre-eminently tourist destinations and ideally suited for a study of this nature. The primary goal of this dissertation was to determine the contribution of tourism to poverty alleviation in Mozambique by assessing Praia Bilene and Macanetta peninsula. The first objective was to describe and understand the link between tourism and poverty. It was found that the traditional definition of poverty no longer applies to most situations. That it is better to view poverty as a lack of access instead of money, access to natural resources, bureaucratic processes, capital markets and entrepreneurship. The review analysed different research methods, looking in depth at the livelihood analysis, ST~EP and MPI. The three pathways namely direct, indirect and induced levels on how tourism affects the poor were also explored. The most challenging area has to be the quantifying of tourism impacts on communities and local livelihoods. Concluding that the measurement of tourism impacts on poverty alleviation is an intricate debate and not easily accomplished. The second objective was to analyse the current status of the tourism industry in Mozambique. With 48% of sub-Sahara living in poverty, the picture in Mozambique is even drearier, with 54% living under the poverty line and 81% living under the $2 poverty line in the country (OPHI, 2013:1), confirming that it is one of the world’s poorest countries. Mozambique’s profile was analysed on its poverty status, tourism development, growth and the tourism impacts on the local communities of Bilene and Macanetta. It was found that several tourism opportunities are scooped up by foreigners and that this causes a major leakage of resources from regions where poverty alleviation by tourism is attempted. At a 7% GDP growth rate Mozambique is making very good progress, but due to being so poor and behind it is not reducing the poverty fast enough. The third objective was to determine the perceptions of two Mozambique communities on tourism impacts and the impact of tourism on their poverty status by incorporating the multi-dimensional poverty index. A perception analysis was done by means of a structured questionnaire presented to random residents from all walks of life at the two specific locations mentioned. The correlation between MPI and perceptions of the impacts of tourism shown that resident’s perceptions of tourism do not influence their deprivation scores negative or positive. It was however determined in an open question that an overwhelming 4 out of 5 people felt that tourism did contribute to poverty alleviation. The perceptions and reality therefore differ. The last objective was to draw conclusions and make recommendations with regard to the contribution of tourism to poverty alleviation in selected Mozambican communities. Conclusions were drawn as to the effectiveness of tourism as a strategic method in the onslaught against poverty in the selected communities. Amongst these conclusions was the fact that poverty seems to be an increasingly complex phenomenon. Due to the difficulty in defining poverty, a wide variety of research methods need to be used to assess the situation. No single approach to impact valuation of tourism on poverty can present all the answers. Concluding in this analysis into poverty and tourism’s relationship it was determined that not only did the factual data show that tourism did not alleviate poverty at these locations but that the population, in stark contrast to empirical proof, determined in their own mind that they perceived a definite improvement due to tourism. Thus residents do not necessarily receive personal benefits from tourism but they are positive towards the tourism industry. This should be utilised by creating opportunities for higher levels of participation in the industry as well as generating more tangible, positive affects for the local population in Mozambique. / MA (Tourism Management), North-West University, Potchefstroom Campus, 2014