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A Method for Computing the Characteristic Polynomial and Determining Semidefiniteness
Mika Hirvensalo, A Method for Computing the Characteristic Polynomial and Determining Semidefiniteness. TUCS Technical Reports 727, Turku Centre for Computer Science, 2005.
Abstract:
We point out that to determine whether a given self-adjoint
matrix <I>A</I> is positive semidefinite
is equivalent to determining whether the characteristic
polynomial of <I>A</I> is <I>alternating</I>,
and give a new algorithm for computing the characteristic
polynomial. The said algorithm uses O(<I>n</I><sup>3</sup> log <I>n</I>)
multiplications and additions, and one division when computing any coefficient
of the characteristic polynomial of an <I>n</I> × <I>n</I> matrix.
The algorithm is essentially division-free,
and hence it can be also used to compute the determinant
for <I>n</I> × <I>n</I> matrices over a great variety of commutative rings.
It takes
O(<I>n</I><sup>3</sup> log <I>n</I>) ring multiplications, additions, <B>Z</B>-module multiplications, and one <B>Z</B>-module
division to compute the determinant.
Files:
Full publication in PDF-format
BibTeX entry:
@TECHREPORT{tHirvensalo05a,
title = {A Method for Computing the Characteristic Polynomial and Determining Semidefiniteness},
author = {Hirvensalo, Mika},
number = {727},
series = {TUCS Technical Reports},
publisher = {Turku Centre for Computer Science},
year = {2005},
keywords = {Determinant, Characteristic Polynomial, Positive Semidefinite, Polynomial Time},
ISBN = {952-12-1649-2},
}
Belongs to TUCS Research Unit(s): FUNDIM, Fundamentals of Computing and Discrete Mathematics