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Johann Radon Institute for Computational and Applied Mathematics (RICAM)
Austrian Academy of Sciences (ÖAW)

MEGA 2007

Effective Methods in Algebraic Geometry

Strobl, Austria, June 25th - 29th

http://www.ricam.oeaw.ac.at/mega2007

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Electronic Proceedings

Abstract

TitlePolynomial Division using Dynamic Arrays, Heaps, and Packed Exponent Vectors
Keywordspolynomial division, data structures, heaps, polynomial GCD, Groebner bases,
AbstractA common data structure that is used for multivariate polynomials
is a linked list of terms sorted in a term ordering.
When dividing polynomials using this data structure,
polynomial addition and subtraction is done using merging.
This can result in poor performance on some kinds of divisons
that commonly arise in practice.

In this paper we consider using an auxilliary heap of pointers
to reduce the number of monomial comparisons needed in the worst case
where the size of the heap is linear in the number of terms
in the quotient(s).
We present variations that are designed to improve performance for
dense polynomials and divisions with large quotients.

We have implemented the heap algorithms in C with an interface from Maple.
We also encode and pack monomials to speed up monomial comparisons.
We give some timings demonstrating that a heap of pointers is efficient.


The Institute is named after the famous Austrian mathematician Johann Radon (1887-1956)

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