#16397: Symbolic cmp
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Reporter: vbraun | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.3
Component: symbolics | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Description changed by vbraun:
Old description:
> In the symbolic ring, cmp implements the print comparison which is
> probably not what you envisioned:
> {{{
> sage: cmp(1, sqrt(2)) # mathematically correct, uses rich comparison
> -1
> sage: cmp(SR(1), sqrt(2)) # unexpectedly, you get the print sort order
> 1
> }}}
New description:
In the symbolic ring, cmp implements the print comparison which is
probably not what you envisioned:
{{{
sage: cmp(1, sqrt(2)) # mathematically correct, uses rich comparison
-1
sage: cmp(SR(1), sqrt(2)) # unexpectedly, you get the print sort order
1
}}}
Everybody who coerces to same parents internally before comparing trips
over this, for example the real lazy field:
{{{
sage: RLF(1) < RLF(sqrt(2))
False
}}}
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Ticket URL: <http://trac.sagemath.org/ticket/16397#comment:2>
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