3 Dec
2005
3 Dec
'05
7:09 p.m.
ld = hi + low as above is not among the bit patterns he lists as valid. If you apply the definition of epsilon to the "normal" long doubles only, then you get a value like the one Paul Bristow computed for NTL's quad_float.
I agree: that explanation is quite explicit when it says it follows Kahan's "double double" and the IEEE spec. So the low part must be normalised so that it's bit's "follow on" from those in the high part. As it stands, 1+numeric_limits<>::epsilon() should evaluate to 1, but we really need to check this out. Does anyone of a numerical inclination, want to run some tests on Darwin? John.