#7957: problems with real_part function
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Reporter: burcin | Owner: burcin
Type: defect | Status: new
Priority: major | Milestone: sage-4.3.2
Component: symbolics | Keywords:
Work_issues: | Author:
Upstream: N/A | Reviewer:
Merged: |
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From the sage-devel thread:
http://groups.google.com/group/sage-devel/t/56519182d53e9cf8
{{{
On Tue, 5 Jan 2010 04:35:27 -0800 (PST)
Håkan Granath <[email protected]> wrote:
> Hi,
>
> It seems computations in QQbar is sometimes much slower in Sage
> 4.3 than in the previous version. Here is an example (I am sorry
> if it is too convoluted):
>
> v1 = sqrt(QQbar(3))
> v2 = QQbar(999/1000*I)
> v3 = (1 + v1)/2 + v2*(-3 - v1)/2
> v4 = (3 - v1)/2 + v2*(1 - v1)/2
> v5 = v3*(1/2) + v4*QQbar(500/999*I)
> v6 = v3*(1/2) + v4*QQbar(-500/999*I)
> v7 = -(v5/v6).conjugate() - QQbar(abs(v5))/v5/v6.conjugate()*QQbar(I)
> v8 = -(v5/v6).conjugate() + QQbar(abs(v5))/v5/v6.conjugate()*QQbar(I)
> v9 = abs(v8)
> v10 = abs(v7)
> v11 = (v7 - v8 + QQbar(v9*v9)*v7 - QQbar(v10*v10)*v8)/\
> (v8.conjugate()*v7 - v7.conjugate()*v8)
> v12 = (v11*QQbar(I) - QQbar(-I)*v11.conjugate())/2/QQbar(I)
> v13 = abs(v12)
> v14 = QQbar(1 - sqrt(1 - 1/(v13*v13)))*v12
> time real(v14)
>
> In Sage 4.3 I get the output:
>
> Exception TypeError: TypeError('Unable to convert number to real
> interval.',) in 'sage.symbolic.pynac.py_is_real' ignored
> CPU times: user 67.94 s, sys: 0.30 s, total: 68.23 s
> Wall time: 68.68 s
> -0.5773508481209188?
>
> In Sage 4.2.1 on the same computer I get the output:
>
> CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
> Wall time: 0.00 s
> -0.5773508481209188?
}}}
This is fallout from #7490. See also #7916 for problems with
`conjugate()`.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/7957>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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