#7587: improve multi_polynomial_libsingular exponent method
---------------------------+------------------------------------------------
Reporter: ylchapuy | Owner: AlexGhitza
Type: enhancement | Status: positive_review
Priority: major | Milestone:
Component: algebra | Keywords:
Work_issues: | Author: Yann Laigle-Chapuy
Upstream: N/A | Reviewer:
Merged: |
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Changes (by SimonKing):
* status: needs_review => positive_review
Comment:
Hi Yann!
First good new: The patch cleanly applies to sage-4.3.alpha0.
Second good news: Using regular expressions (as explained
[http://groups.google.com/group/sage-
devel/browse_thread/thread/20e0fc8f5c5be582 here]) seem to still be faster
in my applications:
{{{
sage: Vars = ['x_'+str(n) for n in range(50)]+['y'+str(n) for n in
range(50)]
sage: R = PolynomialRing(QQ,Vars)
sage: RE = re.compile('([a-zA-Z0-9]+)_([0-9]+)\^?([0-9]*)')
sage: p = R.random_element()
sage: p *= R.random_element()
sage: p *= R.random_element()
sage: p *= R.random_element()
sage: p *= R.random_element()
sage: p *= R.random_element()
sage: L = [(Vars[i],e) for i,e in
enumerate(p.lm().exponents(as_ETuples=False)[0][:50]) if e]
sage: L
[('x_0', 1),
('x_2', 1),
('x_4', 1),
('x_5', 2),
('x_10', 1),
('x_42', 1),
('x_47', 1)]
sage: RE.findall(str(p.lm()))
[('x', '0', ''),
('x', '2', ''),
('x', '4', ''),
('x', '5', '2'),
('x', '10', ''),
('x', '42', ''),
('x', '47', '')]
sage: timeit('L = RE.findall(str(p.lm()))')
625 loops, best of 3: 25.1 µs per loop
sage: timeit('L = [(Vars[i],e) for i,e in
enumerate(p.lm().exponents(as_ETuples=False)[0][:50]) if e] ')
625 loops, best of 3: 11.2 µs per loop
}}}
I can also confirm that the computation time with the
{{{as_ETuples=False}}} option is reduced by 90%. So, I can give it a
positive review.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/7587#comment:2>
Sage <http://www.sagemath.org>
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