Memory Access Patterns for Cellular Automata Using GPGPUs

Today\u27s graphical processing units have hundreds of individual processing cores that can be used for general purpose computation of mathematical and scientific problems. Due to their hardware architecture, these devices are especially effective when solving problems that exhibit a high degree of spatial locality. Cellular automata use small, local neighborhoods to determine successive states of individual elements and therefore, provide an excellent opportunity for the application of general purpose GPU computing. However, the GPU presents a challenging environment because it lacks many of the features of traditional CPUs, such as automatic, on-chip caching of data. To fully realize the potential of a GPU, specialized memory techniques and patterns must be employed to account for their unique architecture. Several techniques are presented which not only dramatically improve performance, but, in many cases, also simplify implementation. Many of the approaches discussed relate to the organization of data in memory or patterns for accessing that data, while others detail methods of increasing the computation to memory access ratio. The ideas presented are generic, and applicable to cellular automata models as a whole. Example implementations are given for several problems, including the Game of Life and Gaussian blurring, while performance characteristics, such as instruction and memory accesses counts, are analyzed and compared. A case study is detailed, showing the effectiveness of the various techniques when applied to a larger, real-world problem. Lastly, the reasoning behind each of the improvements is explained, providing general guidelines for determining when a given technique will be most and least effective

Liquid notations:A common language of transitions

If we lived in a liquid world, the concept of a "machine" would make no sense. Liquid life is metaphor and apparatus that discusses the consequences of thinking, working, and living through liquids. It is an irreducible, paradoxical, parallel, planetary-scale material condition, unevenly distributed spatially, but temporally continuous. It is what remains when logical explanations can no longer account for the experiences that we recognize as part of "being alive."Liquid Life references a third-millennial understanding of matter that seeks to restore the agency of the liquid soul for an ecological era, which has been banished by reductionist, "brute" materialist discourses and mechanical models of life. Offering an alternative worldview of the living realm through a "new materialist" and "liquid" study of matter, Armstrong conjures forth examples of creatures that do not obey mechanistic concepts like predictability, efficiency, and rationality. With the advent of molecular science, an increasingly persuasive ontology of liquid technologies can be identified. Through the lens of lifelike dynamic droplets, the agency for these systems exists at the interfaces between different fields of matter/energy that respond to highly local effects, with no need for a central organizing system.Liquid Life seeks an alternative partnership between humanity and the natural world. It provokes a re-invention of the languages of the living realm to open up alternative spaces for exploration, including contributor Rolf Hughes’ "angelology" of language, which explores the transformative invocations of prose poetry, and Simone Ferracina’s graphical notations that help shape our concepts of metabolism, upcycling, and designing with fluids. A conceptual and practical toolset for thinking and designing, liquid life reunites us with the irreducible "soul substance" of living things, which will neither be simply "solved," nor go away

11th International Coral Reef Symposium Abstracts

https://nsuworks.nova.edu/occ_icrs/1001/thumbnail.jp

Adaptation of population size in genetic algorithms

Este documento describe un algoritmo genético combinado con un autómata celular que utiliza un esquema de población celular para mantener diversidad en la población y determinar automáticamente el tamaño de la población. Los individuos del algoritmo genético son organizados en un autómata celular de 2 dimensiones, donde los individuos son considerados activos o inactivos en cada iteración del proceso evolutivo de acuerdo con una función de transición de estados configurada en el autómata celular. Solo los individuos activos son sujetos al proceso de evolución y cuando múltiples padres son requeridos por un operador genético, un esquema de selección local es utilizado, donde los individuos activos en la vecindad pueden ser seleccionados como padres. Un modelo de Explosiones Cámbricas y Extinción Masivas es introducido en el esquema, permitiendo controlar la extinción o sobrepoblación de individuos activos en la población. Experimentos muestran que el esquema propuesto es capaz de mantener diversidad en la población mientras encuentra buenas soluciones en un número apropiado de evaluaciones de la función de aptitud. / Abstract. This paper describes an evolutionary algorithm (EA) which combines cellular automata, Cambrian explosions and massive extinctions ideas in order to maintain diversity and automatically determine the population’s size of the EA. Individuals are organized in a two-dimensional grid (2-dimensional cellular automaton surface) and are considered active or inactive according to the cellular automaton state. The individual state is updated according to the cellular automaton state rules at each step (iteration) of the evolutionary process. Only active individuals are subject to evolution by applying one of the genetic operators and considering just their active neighbors (when multiple parents are required). Depending on the total number of active individuals, a Cambrian explosion or a massive extinction operation is applied, in a random fashion to control the size of the population. We presented a novel genetic diversity analysis using a hierarchical clustering to examine individuals genotype and identify natural population taxonomies. Experiments show that the proposed scheme is able to maintain diversity and find near optimal solutions in an appropriated number of fitness evaluations.Magíster en ingeniería de sistemas y computaciónMaestrí