Finding Morton-Like Layouts for Multi-Dimensional Arrays Using Evolutionary Algorithms

The layout of multi-dimensional data can have a significant impact on the efficacy of hardware caches and, by extension, the performance of applications. Common multi-dimensional layouts include the canonical row-major and column-major layouts as well as the Morton curve layout. In this paper, we describe how the Morton layout can be generalized to a very large family of multi-dimensional data layouts with widely varying performance characteristics. We posit that this design space can be efficiently explored using a combinatorial evolutionary methodology based on genetic algorithms. To this end, we propose a chromosomal representation for such layouts as well as a methodology for estimating the fitness of array layouts using cache simulation. We show that our fitness function correlates to kernel running time in real hardware, and that our evolutionary strategy allows us to find candidates with favorable simulated cache properties in four out of the eight real-world applications under consideration in a small number of generations. Finally, we demonstrate that the array layouts found using our evolutionary method perform well not only in simulated environments but that they can effect significant performance gains -- up to a factor ten in extreme cases -- in real hardware

The Opie Compiler: from Row-major Source to Morton-ordered Matrices

The Opie Project aims to develop a compiler to transform C codes written for row-major matrix representation into equivalentcodes for Morton-order matrix representation, and to apply its techniques to other languages. Accepting a possible reduction in performance weseek to compile libraries of usable code to support future developmentofnew algorithms better suited to Morton-ordered matrices

Rural life in English poetry of the mid-eighteenth century

This thesis examines several mid-eighteenth century poems, assessing their portrayal of rural life, its literary and historical significance, and the aesthetic and ideological issues it presents. An introductory essay on developments in rural poetry sets the scene for two extended essays. The first essay is a comparative reading of the subject of rural labour in three poems: James Thomson’s The Seasons (1726-44), Stephen Duck’s The Thresher’s Labour (1730, 1736) and Mary Collier’s The Woman’s Labour (1739). The viewpoints of a professional poet (Thomson), a farm labourer (Duck), and a working woman (Collier) are compared in relation to kinds of work all three address as well as to individual labouring subjects. The responses of the three poets to such related issues as folk traditions, forms of charity and other ‘compensations’, are also compared. Some surprising similarities as well as instructive differences are located; and an interesting picture of idealistic and realistic, male-oriented and female-oriented attitudes to labour and labour-related themes emerges