Jonathan Richard Shewchuk

Jonathan Richard Shewchuk developed adaptive exact arithmetic methods for robust computational geometry predicates. Orientation and incircle tests depend on the sign of a determinant; an incorrectly rounded sign near zero can corrupt the geometric decisions of an algorithm. His method spends additional precision only when needed to establish the correct sign.^[ref]

For example, three nearly collinear points may give an orientation determinant extremely close to zero even when their coordinates are individually unexceptional. A fast approximate evaluation can resolve an easy case, while a difficult case triggers more exact work. This connects numerical accuracy to a discrete geometric decision, not merely to the number of printed decimal places.

Homepage: people.eecs.berkeley.edu/~jrs/