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Brian J. d'Auriol, Foundations of the Polytope Model, Departmental Seminar, Computer Science Seminar Series, Oct. 22, 1998, Department of Mathematics and Computer Science, The University of Akron, Akron, Ohio, USA.
	 
	
	Abstract
	
	 
In recent years, research endeavors in the broadly accepted areas of 
systolics, restructuring compilers and data dependency analysis have become 
identified with a geometric framework for representing certain program structures 
(e.g. for loops) commonly found in 
high-level language programs. That is, a certain coherent pattern in the 
philosophy, motivation and approach of recent endeavors may be discerned. In 
particular, the term Polytope Model has become established to refer to formal 
theory relating to such geometric interpretations. A significant amount of 
research regarding the polytope model stems    from work relating to restructuring 
compilers, particularly, loop analysis. Of these techniques, it is the usual 
case to: (a) begin with some loop-nest, (b) translate the loop-nest into a 
geometric form according to the principals of the polytope model, (c) perform 
some analysis (which would usually be data dependency analysis), (d) perform 
some manipulation of the geometric representation (which would normally be 
some form of loop manipulation, for example, loop reversal) and (e) 
re-translate the modified geometric representation back into a loop-nest 
form. A succinct description of this application of the polytope model 
is  
   loop-nest ---> geometric-representation ---> new-loop nest.  
This talk will present the foundations of the polytope model in the context 
of its applications to restructuring compilers. Discussed is the correspondence 
between loop-nests and geometric objects, the definition of iteration and 
memory spaces, the application to parallel programming, computational aspects 
and linguistic and non-linguistic carried semantics of the geometric object. 
The notion of an Active Polytope is introduced to represent the necessary 
linguistic carried semantics.  |