On Sat, 27 Nov 2010 18:23:48 -0500, Terry Reedy wrote: >> Therefore, to implement this multiplication operation I need to have a >> way to verify that the float tuples C and D are "equal". > > I might try the average relative difference: > sum(abs((i-j)/(i+j)) for i,j in zip(C,D))/n # assuming lengths constant
The division is unstable if i and j are close to zero. For scalars, I'd use: abs(i-j) <= epsilon * (1 + abs(i+j)) This amounts to a relative error check for large values and an absolute error check for values close to zero. For a vector, I'd check that the above holds for all pairs. -- http://mail.python.org/mailman/listinfo/python-list