#11309: Sage sees -x +y > 0, -y + x >= 0, and x -y > 0 as equivalent
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Reporter: tnv |
Owner: burcin
Type: defect |
Status: needs_review
Priority: major |
Milestone: sage-5.1
Component: symbolics |
Resolution:
Keywords: inequality equality relational sd31 __richcmp__ sd40.5 |
Work issues:
Report Upstream: N/A |
Reviewers: Karl-Dieter Crisman, ThanhVu Nguyen
Authors: Keshav Kini, Burcin Erocal |
Merged in:
Dependencies: |
Stopgaps:
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Comment (by kcrisman):
Hmm, this is a big slowdown in at least one case.
{{{
# old
sage: timeit("(x < y) != (y > x)")
625 loops, best of 3: 2.76 µs per loop
# new
sage: timeit("(x < y) != (y > x)")
625 loops, best of 3: 13.3 µs per loop
}}}
It looks like it's fairly constantly adding this. Here, in the much
slower checking of a list
{{{
# old
sage: timeit("(x - 1 < 0) in [x - 2 < 0]")
625 loops, best of 3: 104 µs per loop
# new
sage: timeit("(x - 1 < 0) in [x - 2 < 0]")
625 loops, best of 3: 116 µs per loop
}}}
Here's another one.
{{{
# old
sage: timeit("(y > y) != (y > y) ")
625 loops, best of 3: 2.24 µs per loop
# new
sage: timeit("(y > y) != (y > y) ")
625 loops, best of 3: 8.45 µs per loop
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11309#comment:44>
Sage <http://www.sagemath.org>
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