PSEUDO: applications of streams and lazy evaluation to integrable models

Abstract

Procedures to manipulate pseudo-differential operators in MAPLE are implemented in the program PSEUDO to perform calculations with integrable models. We use lazy evaluation and streams to represent and operate with pseudo-differential operators. No order of truncation is needed since terms are produced on demand. We give a series of concrete examples. Program summary Title of program: PSEUDO Catalogue identifier: ADUO Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADUO Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions: None Computers: IBM PC Operating systems under which the program has been tested: Windows systems Programming language used: MAPLE V Release 8 Memory required to execute with typical data: Depends strongly on the problem No. of lines in distributed program, including test data, etc.: 737 No. of bytes in distributed program, including test data, etc.: 8822 Distribution format: tar.gz Nature of mathematical problem: Determination of equations of motion and conserved charges in the theory of integrable models Methods of solution: Pseudo-differential Lax operators Restrictions on the complexity of the problem: Handles only one-dimensional pseudo-differential operators with scalar coefficients Typical running time: This depends strongly on the problem to be solved, usually taking from a few seconds to a few minutes Unusual features of the program: Use of delayed evaluation and streams