On 2018-02-04, Simon King <simon.k...@uni-jena.de> wrote:
> On 2018-02-04, Thierry <sage-googlesu...@lma.metelu.net> wrote:
>> On Sun, Feb 04, 2018 at 10:24:55PM +0000, Simon King wrote:
>> What is wrong ?
>
> val is a NEGATIVE real number converted into SR. val evaluates POSITIVE,
> even though the conversion of val into RR still evaluates negative.

Ouch, sorry, when I posted I was apparently editing stuff in a wrong
way.

So, here is the example:
 sage: val = pi - 2286635172367940241408/1029347477390786609545*sqrt(2)
 sage: bool(val<0)
 False
 sage: bool(val>0)
 True

Hence, val evaluates positive. However, it represents a negative real
number:
 sage: RR(val)
 -4.44089209850063e-16

Sorry, in my original post I was starting from that number and got a
couple of things wrong.

Note that evaluating val to higher precision still gives a negative
number, although a clearly different one:
 sage: RR(RealField(2000)(val))
 -5.68242325601396e-24

Going to even higher precision doesn't change things.

So, is that a bug, after all? val being positive, RR(val) being
negative?

Cheers,
Simon

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