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4.3.3 Subdivision Methods

Subdivision methods [221,333,286,392,402,133] are generally efficient (in finding simple intersections) and stable. Therefore, they are the most frequently used methods in practice. As we will see, they can be combined with interval methods to numerically guarantee that certain subdomains do not contain solutions. Interval Newton methods [273,131,191,27,159,158] are a promising class of subdivision methods. However, the subdivision methods are not as general as algebraic methods, since they are only capable of isolating zero-dimensional solutions. Furthermore, although the chances, that all roots have been found, increase as the resolution tolerance is lowered, there is no certainty that each root has been extracted/isolated. Subdivision methods typically do not provide a guarantee as to how many roots there may be in the remaining subdomains. However, if these subdomains are very small, the existence of a (single) root within these subdomains is a typical assumption. Lastly, subdivision techniques provide no explicit information about root multiplicities without additional computation. Despite these drawbacks, subdivision methods are very useful in practice and are further described below.


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Next: 4.4 Projected Polyhedron algorithm Up: 4.3 Classification of global Previous: 4.3.2 Homotopy (Continuation) Methods   Contents   Index
December 2009