Re: (expt 2 #c(2d0 0))?



"Barry" == Barry Margolin <barmar@xxxxxxxxxxxx> writes:

Barry> In article
>> > What makes you think the origial 2.0 and 3.0 are exact? They
>> > came from
>>
>> On the other hand, what makes you think they weren't exact?
>> Any epsilon you want to ascribe is outside of the computation.

Barry> When using transcendental functions, exact numbers are
Barry> extremely rare. Except for special cases, all their
Barry> results are irrational, so the floating point value will be
Barry> an approximation.

Certainly, but saying the result of a transcendental function is a
floating-point approximation doesn't give you freedom to return any
value. There's a certain expectation that some care is taken and the
value is as close to the true value as reasonably possible.

Perhaps I'm being unreasonable. :-)

I agree that the spec doesn't explicitly say what the accuracy of
(expt 2 #c(-2d0 -1d0)) should be. It would be nice if the more
accurate value were returned, since that doesn't violate the spec,
AFAICT.

Ray
.



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