I like his notion that IEEE errors result from sloppiness. So here are 2 "non-sloppy" version of the computation of the sign of a determinant: https://github.co

I like his notion that IEEE errors result from sloppiness. So here are 2 "non-sloppy" version of the computation of the sign of a determinant: https://github.com/bjornharrtell/jsts/blob/master/src/jsts/algorithm/RobustDeterminant.js https://github.com/bjornharrtell/jsts/blob/master/src/jsts/a... http://www.cs.cmu.edu/afs/cs/project/quake/public/code/predicates.c http://www.cs.cmu.edu/afs/cs/project/quake/public/code/predi... Remember, the determinant value is not the rounded value of the exact computation with those things unless it is is zero, it's still "sloppy" if it's far from zero. You get only 1 bit of guaranteed accuracy in a 64bits FP number if the result is not zero. I think there is a little bit to "sloppiness" in the fact that we carry very inexact results in FP. Even "good enough" FP computation is PhD level.