Author: Assefaw Hadish GebremedhinPublisher:
ISBN:
Category :
Languages : en
Pages : 46
Book Description
Scalable, Shared Memory Parallel Graph Coloring Heuristics
Author: Assefaw Hadish GebremedhinPublisher:
ISBN:
Category :
Languages : en
Pages : 46
Book Description
Shared-Memory Parallelism Can be Simple, Fast, and Scalable
Author: Julian ShunPublisher: Morgan & Claypool
ISBN: 1970001895
Category : Computers
Languages : en
Pages : 445
Book Description
Parallelism is the key to achieving high performance in computing. However, writing efficient and scalable parallel programs is notoriously difficult, and often requires significant expertise. To address this challenge, it is crucial to provide programmers with high-level tools to enable them to develop solutions easily, and at the same time emphasize the theoretical and practical aspects of algorithm design to allow the solutions developed to run efficiently under many different settings. This thesis addresses this challenge using a three-pronged approach consisting of the design of shared-memory programming techniques, frameworks, and algorithms for important problems in computing. The thesis provides evidence that with appropriate programming techniques, frameworks, and algorithms, shared-memory programs can be simple, fast, and scalable, both in theory and in practice. The results developed in this thesis serve to ease the transition into the multicore era. The first part of this thesis introduces tools and techniques for deterministic parallel programming, including means for encapsulating nondeterminism via powerful commutative building blocks, as well as a novel framework for executing sequential iterative loops in parallel, which lead to deterministic parallel algorithms that are efficient both in theory and in practice. The second part of this thesis introduces Ligra, the first high-level shared memory framework for parallel graph traversal algorithms. The framework allows programmers to express graph traversal algorithms using very short and concise code, delivers performance competitive with that of highly-optimized code, and is up to orders of magnitude faster than existing systems designed for distributed memory. This part of the thesis also introduces Ligra+, which extends Ligra with graph compression techniques to reduce space usage and improve parallel performance at the same time, and is also the first graph processing system to support in-memory graph compression. The third and fourth parts of this thesis bridge the gap between theory and practice in parallel algorithm design by introducing the first algorithms for a variety of important problems on graphs and strings that are efficient both in theory and in practice. For example, the thesis develops the first linear-work and polylogarithmic-depth algorithms for suffix tree construction and graph connectivity that are also practical, as well as a work-efficient, polylogarithmic-depth, and cache-efficient shared-memory algorithm for triangle computations that achieves a 2–5x speedup over the best existing algorithms on 40 cores. This is a revised version of the thesis that won the 2015 ACM Doctoral Dissertation Award.
Scalable Parallel Algorithms and Implementations for Large-Scale Graph Analyses
Author: Hao LuPublisher:
ISBN:
Category :
Languages : en
Pages : 131
Book Description
Different heuristics and design techniques presented in this dissertation can potentially be adapted into the broader context of parallelizing other graph operations that also have a similar irregular, and/or iterative structure to their computation.
Graph-Theoretic Concepts in Computer Science
Author: Ulrik BrandesPublisher: Springer
ISBN: 3540400648
Category : Computers
Languages : en
Pages : 324
Book Description
The 26th International Workshop on Graph-Theoretic Concepts in Computer Science (WG 2000) was held at Waldhaus Jakob, in Konstanz, Germany, on 15{ 17 June 2000. It was organized by the Algorithms and Data Structures Group of the Department of Computer and Information Science, University of K- stanz, and sponsored by Deutsche Forschungsgemeinschaft (DFG) and Univ- sit ̈atsgesellschaft Konstanz. The workshop aims at uniting theory and practice by demonstrating how graph-theoretic concepts can be applied to various areas in computer science, or by extracting new problems from applications. The goal is to present recent research results and to identify and explore directions for future research. The workshop looks back on a remarkable tradition of more than a quarter of a century. Previous Workshops have been organized in various places in Europe, and submissions come from all over the world. This year, 57 attendees from 13 di erent countries gathered in the relaxing atmosphere of Lake Constance, also known as the Bodensee. Out of 51 submis- ons, the program committee carefully selected 26 papers for presentation at the workshop. This selection re?ects current research directions, among them graph and network algorithms and their complexity, algorithms for special graph cl- ses, communication networks, and distributed algorithms. The present volume contains these papers together with the survey presented in an invited lecture by Ingo Wegener (University of Dortmund) and an extended abstract of the invited lecture given by Emo Welzl (ETH Zuric ̈ h).
Experiments with Parallel Graph Coloring Heuristics
Author: University of Wisconsin--Madison. Computer Sciences DeptPublisher:
ISBN:
Category : Graph theory
Languages : en
Pages : 24
Book Description
Abstract: "We report on experiments with a new hybrid graph coloring algorithm, which combines a parallel version of Morgenstern's S- Impasse algorithm [20], with exhaustive search. We contribute new test data arising in five different application domains, including register allocation and class scheduling. We test our algorithms both on this test data and on several types of randomly generated graphs. We compare our parallel implementation, which is done on the CM-5, with two simple heuristics, the Saturation algorithm of Brélaz [4] and the Recursive Largest First (RLF) algorithm of Leighton [18]. We also compare our results with previous work reported by Morgenstern [20] and Johnson et al. [13]. Our main results are as follows: On the randomly generated graphs, the performance of Hybrid is consistently better than the sequential algorithms, both in terms of speed and number of colorings produced. However, on large random graphs, our algorithms do not come close to the best colorings found by other time-intensive algorithms such as the XRLF algorithm of Johnson et al. [13] and Morgenstern's tuned S-Impasse algorithm. Of the five types of test data, three are easily colored even by the simple RLF and Saturation heuristics; one (the class scheduling data) is optimally colored by Hybrid but not by the simple heuristics, and one appears to be very hard. However, it should not be concluded that coloring is 'easy' in most applications. In several cases, such as the class and exam scheduling graphs, finding an optimal coloring is not sufficient to solve the problem at hand, but rather colorings satisfying additional restrictions are really needed. The Hybrid algorithm parallelizes well. This appears to be for three main reasons. First, the number of iterations needed by the S-impasse decreases as the number of processors increase. Second, in the exhaustive search algorithm the work involved in expanding the search tree is effectively shared among the processors. Third, on some tests, the S-Impasse and Exhaustive-Search procedures progress in a symbiotic fashion, one using a good coloring obtained by the other as a basis for further improvement. Overall, we are satisfied that our parallel algorithm effectively exploits the processing power of the CM-5, and that further work on a hybrid algorithm can lead to even better results. Since the performance of all the implemented algorithms on random graphs does not correlate well with their performance on application data, we conclude that further effort spent in collecting application data is well justified, and suggest that new generators, which model the structure of application data, be investigated."
Graph Coloring in Optimization Revisited
Author: Assefaw Hadish GebremedhinPublisher:
ISBN:
Category :
Languages : en
Pages : 48
Book Description
Author: Jean R. S. Blair
Author: Yngve Lamo
Author: Magne Haveraaen
Author: Petter Kristiansen