# Real Algebraic Numbers: Complexity Analysis and Experimentations

1 GALAAD - Geometry, algebra, algorithms CRISAM - Inria Sophia Antipolis - Méditerranée , UNS - Université Nice Sophia Antipolis, CNRS - Centre National de la Recherche Scientifique : UMR6621

Abstract : We present algorithmic, complexity and implementation results concerning real root isolation of a polynomial of degree $d$, with integer coefficients of bit size $\le\tau$, using Sturm -Habicht sequences and the Bernstein subdivision solver.
In particular, we unify and simplify the analysis of both methods and we give an asymptotic complexity bound of $\sOB d^4 \tau^2$.
This matches the best known bounds.
Moreover, we generalize this to cover the non-squarefree polynomials and show that within the same complexity we can also compute the multiplicities of the roots.
We also consider algorithms for sign evaluation, comparison of real algebraic numbers and simultaneous inequalities SI and we improve the known bounds at least by a factor of $d$.
Finally, we present our C++ implementation in Synaps and experiments on various data sets.

Keywords : DESCARTES- RULE BERNSTEIN BASIS SUBDIVISION BIT COMPLEXITY SEPARATION BOUND POLYNOMIAL EQUATION ALGEBRAIC NUMBER

Author: Ioannis Z.
Emiris - Bernard Mourrain - Elias P.
Tsigaridas -

Source: https://hal.archives-ouvertes.fr/