#13213: Comparisons in real number field
-------------------------------------------------+--------------------------
       Reporter:  vdelecroix                     |         Owner:  vdelecroix
           Type:  enhancement                    |        Status:  new       
       Priority:  major                          |     Milestone:  sage-5.2  
      Component:  number fields                  |    Resolution:            
       Keywords:  real number field, comparison  |   Work issues:            
Report Upstream:  N/A                            |     Reviewers:            
        Authors:  Vincent Delecroix              |     Merged in:            
   Dependencies:                                 |      Stopgaps:            
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Description changed by vdelecroix:

Old description:

> Provide the order from RR for number field embedded in RR as in
> {{{
> sage: K.<sqrt2> = NumberField(x^2 - 2, 'sqrt2', embedding=1.4142)
> sage: sqrt2 - 1 > 0
> True
> sage: sqrt2 < 2
> True
> }}}
>
> There is a patch for quadratic field. Another one is comming for general
> number fields.

New description:

 Provide the order from RR for number field embedded in RR as in
 {{{
 sage: K.<sqrt2> = NumberField(x^2 - 2, 'sqrt2', embedding=1.4142)
 sage: sqrt2 - 1 > 0
 True
 sage: sqrt2 < 2
 True
 }}}

 There is a patch for quadratic field. Another one is comming for general
 number fields.

 Timings with the patch
 {{{
 sage: K.<sqrt2> = QuadraticField(2,'sqrt2',embedding=1.4142)
 sage: b = (5*sqrt2 + 14)/5
 sage: a = (3*sqrt2 + 18)/7
 sage: %timeit a < b
 625 loops, best of 3: 6.68 µs per loop
 }}}
 Timings without the patch
 {{{
 sage: sage: K.<sqrt2> = QuadraticField(2,'sqrt2',embedding=1.4142)
 sage: a = (3*sqrt2 + 18)/7
 sage: b = (5*sqrt2 + 14)/5
 sage: %timeit a < b
 625 loops, best of 3: 478 ns per loop
 }}}
 }}}

--

-- 
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13213#comment:2>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica, 
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