This paper is concerned with a robust geometric predicate for the 2D orientation problem. Recently, a fast and accurate floating-point summation algorithm is investigated by Rump, Ogita and Oishi, which provably outputs a result faithfully rounded from the exact value of the summation of floating-point numbers. We optimize their algorithm for applying it to the 2D orientation problem which requires only a correct sign of a determinant of a $3\times 3$ matrix. Numerical results illustrate that our algorithm works fairly faster than the state-of-the-art algorithm in various cases.
"Adaptive and Efficient Algorithm for 2D Orientation Problem." Japan J. Indust. Appl. Math. 26 (2-3) 215 - 231, October 2009.