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Matthew J. Sottile

Publications and source records attributed to Matthew J. Sottile.

3 recordsLinked to original sources

An energy-based interaction model for population opinion dynamics with topic coupling

We introduce a new, and quite general variational model for opinion dynamics based on pairwise interaction potentials and a range of opinion evolution protocols ranging from random interactions to global synchronous flows in the opinion state space. The model supports the concept of topic "coupling", allowing opinions held by individuals to be changed via indirect interaction with others on different subjects. Interaction topology is governed by a graph that determines interactions. Our model, which is really a family of variational models, has, as special cases, many of the previously established models for the opinion dynamics. After introducing the model, we study the dynamics of the special case in which the potential is either a tent function or a constructed bell-like curve. We find that even in these relatively simple potential function examples there emerges interesting behavior. We also present results of preliminary numerical explorations of the behavior of the model to motivate questions that can be explored analytically.

physics.soc-ph

Deriving program transformations by demonstration

Automatic code transformation in which transformations are tuned for specific applications and contexts are difficult to achieve in an accessible manner. In this paper, we present an approach to build application specific code transformations. Our approach is based on analysis of the abstract syntax representation of exemplars of the essential change to the code before and after the transformation is applied. This analysis entails a sequence of steps to identify the change, determine how to generalize it, and map it to term rewriting rules for the Stratego term rewriting system. The methods described in this paper assume programs are represented in a language-neutral term format, allowing tools based on our methods to be applied to programs written in the major languages used by computational scientists utilizing high performance computing systems.

cs.PL

ForOpenCL: Transformations Exploiting Array Syntax in Fortran for Accelerator Programming

Emerging GPU architectures for high performance computing are well suited to a data-parallel programming model. This paper presents preliminary work examining a programming methodology that provides Fortran programmers with access to these emerging systems. We use array constructs in Fortran to show how this infrequently exploited, standardized language feature is easily transformed to lower-level accelerator code. The transformations in ForOpenCL are based on a simple mapping from Fortran to OpenCL. We demonstrate, using a stencil code solving the shallow-water fluid equations, that the performance of the ForOpenCL compiler-generated transformations is comparable with that of hand-optimized OpenCL code.

cs.PL