Efficient exact arithmetic for computational geometry

Abstract

We experiment with exact integer arithmetic to implement primitives for geometric algorithms. Naive use of exact arithmetic—either modular or multiprecision integer—increases execution time dramatically over the use of floating-point arithmetic. By combining tuned multiprecision integer arithmetic and a floating-point filter based on interval analysis, we can obtain the effect of exact integer arithmetic at a cost close to that of floating-point arithmetic. We describe an experimental expression compiler that conveniently packages our techniques.