#12923: Comparison of vectors is O(n) even in the simple cases
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Reporter: hivert | Owner: jason, was
Type: defect | Status: new
Priority: major | Milestone: sage-5.1
Component: linear algebra | Keywords: vector equality
Work issues: | Report Upstream: N/A
Reviewers: | Authors: Florent Hivert
Merged in: | Dependencies:
Stopgaps: |
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Comparison of large vectors in Sage is slow in a surprising way: even if
all
the entries of the vectors are different, the cost is proportional to the
length of the vector instead of having constant cost !
{{{
sage: l = 1000; m0 = vector(ZZ, [0]*l); m1 = vector(ZZ, [1]*l)
sage: %timeit m0 == m1
625 loops, best of 3: 656 盜 per loop
sage: l = 10000; m0 = vector(ZZ, [0]*l); m1 = vector(ZZ, [1]*l)
sage: %timeit m0 == m1
125 loops, best of 3: 5.66 ms per loop
sage: l = 100000; m0 = vector(ZZ, [0]*l); m1 = vector(ZZ, [1]*l)
sage: %timeit m0 == m1
5 loops, best of 3: 59.1 ms per loop
}}}
This seems to affect all the dense vectors independently from the base
ring.
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12923>
Sage <http://www.sagemath.org>
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