Precision and CD's
Stephane.Dalmas at sophia.inria.fr
Tue Jul 20 16:43:16 CEST 1999
> > Other considerations:
> > The major advantage of floats/ bigfloats is that the cost of
> > operations is mostly a function of the desired precision, and
> > not (usually) the value. The usual
> > operations include sqrt, exp, log, sin, cos etc. as well as +-*/.
> If that's what you consider the essence of bigfloats, then the
> representation should include a specification for the precision -- but
> several people on the list (including you) have argued vehemently against
> this: "bigfloats are exact rationals".
I may have miss a point or two in this discussion, but I agree with Richard
here. A bigfloat is an exact rational, but it is subject to a strange
arithmetic that is NOT the arithmetic on rational numbers.
PS Not all IEEE floating-point "values" are rationals as we know them. That
is a reason to have them primitive (at least the most common double
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