use the cross product to examine whether they're collinear. points A,B,C: AB*BC =? 0
On 5/27/07, Feng <[EMAIL PROTECTED]> wrote: > > > Hi all! > > Given 3 points in 3D, what is the fast and numerically stable way to > test if they form a triangle? > > I am thinking computing the determinant of the square matrix formed by > the 3 points and testing if the determinant is nonzero. But I am not > sure. > > What about the case for high dimensions, i.e. 4D, 5D ... > > Thanks! > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to algogeeks@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/algogeeks -~----------~----~----~----~------~----~------~--~---