2,007 research outputs found
Small clique number graphs with three trivial critical ideals
The critical ideals of a graph are the determinantal ideals of the
generalized Laplacian matrix associated to a graph. In this article we provide
a set of minimal forbidden graphs for the set of graphs with at most three
trivial critical ideals. Then we use these forbidden graphs to characterize the
graphs with at most three trivial critical ideals and clique number equal to 2
and 3.Comment: 33 pages, 3 figure
Hardware Parallelization of Cores Accessing Memory with Irregular Access Patterns
This project studies FPGA-based heterogeneous computing architectures with the objective of
discovering their ability to optimize the performances of algorithms characterized by irregular
memory access patterns. The example used to achieve this is a graph algorithm known as Triad
Census Algorithm, whose implementation has been developed and tested.
First of all, the triad census algorithm is presented, explaining the possible variants and
reviewing the existing implementations upon different architectures. The analysis focuses on
the parallelization techniques which have allowed to boost performance, thus reducing execution
time. Besides, the study tackles the OpenCL programming model, the standard used to develop
the final application. Special attention is paid to the language details that have motivated some
of the most important design decisions.
The dissertation continues with the description of the project implementation, including
the application objectives, the system design, and the different variants developed to enhance
algorithm performance.
Finally, some of the experimental results are presented and discussed. All implemented
versions are evaluated and compared to decide which is the best in terms of scalability and
execution time
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