E-methods for fixed point equations f(x)=x

Autor: Siegfried M. Rump, E. Kaucher
Rok vydání: 1982
Předmět:
Zdroj: Computing. 28:31-42
ISSN: 1436-5057
0010-485X
DOI: 10.1007/bf02237993
Popis: This paper provides newly implemented [11], [13] and widely applicable methods for, computing inclusion (i. e. a containing interval) (Einschliesung) of the solution of a fixed point equationf(x)=x as well as autmatic verification the existence (Existenz) and uniqueness (Eindeutigkeit) of the solution. These methods make essential use of a new computer arithmetic defined by semimorphisms as developed in [7] and [8]. We call such methods E-Methods in correspondance to the three German words. A priori estimations such as a bound for a Lipschitz constant etc. are not required by the new algorithm. So the algorithm including the a posteriori proof of existence and uniqueness of the fixed point is programmable on computers for linear as well as for nonlinear problems. This is a key feature of our results. The computations produced by E-methods deliver answers the components of which have accuracy better than 10−t+1 (wheret denotes the mantissa length employed in the computer).
Databáze: OpenAIRE