TY - JOUR T1 - An Algorithm that Localizes and Counts the Zeros of a $C^2$-Function AU - Hungerbühler , Norbert AU - Wu , Rui JO - Numerical Mathematics: Theory, Methods and Applications VL - 2 SP - 320 EP - 333 PY - 2020 DA - 2020/03 SN - 13 DO - http://doi.org/10.4208/nmtma.OA-2019-0077 UR - https://global-sci.org/intro/article_detail/nmtma/15450.html KW - Number of zeros on an interval. AB -

We describe an algorithm that localizes the zeros of a given real $C^2$-function $f$ on an interval $[a,b]$. The algorithm generates a sequence of subintervals which contain a single zero of $f$. In particular, the exact number of zeros of $f$ on $[a,b]$ can be determined in this way. Apart from $f$, the only additional input of the algorithm is an upper and a lower bound for $f''$. We also show how the intervals determined by the algorithm can be further refined until they are contained in the basin of attraction of the Newton method for the corresponding zero.