#9885: slow coercion from integer mod ring to integer ring
-------------------------+-------------------------------------------------
Reporter: | Owner: tbd
dmharvey | Status: needs_review
Type: | Milestone:
defect | Resolution:
Priority: major | Merged in:
Component: | Reviewers:
performance | Work issues:
Keywords: | Commit:
Authors: Nils | c04c8b5cd99d9614d52dc65df8bb1b07a497ff5a
Bruin | Stopgaps:
Report Upstream: N/A |
Branch: |
u/nbruin/9885 |
Dependencies: |
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Comment (by nbruin):
Replying to [comment:7 mmezzarobba]:
> I already tried after seeing your version, and the hybrid solution was
the slowest of the three (by a significant amount). I didn't try to
understand why.
Hm, something must have gone wrong in the hybridization then. With this
test code:
{{{
def test1(n,x):
cdef long N=n
for i in range(N):
t1(x)
def test2(n,x):
cdef long N=n
for i in range(N):
t2(x)
def t1(o):
cdef object A=getattr(o,"_integer_",None)
if A is not None:
return A
else:
return None
def t2(o):
try:
return o._integer_
except AttributeError:
return None
}}}
I get
{{{
sage: R=GF(5)
sage: a=R(1)
sage: timeit('test1(100000,a)')
125 loops, best of 3: 6.94 ms per loop
sage: timeit('test2(100000,a)')
125 loops, best of 3: 7.49 ms per loop
sage: timeit('test1(100000,R)')
5 loops, best of 3: 123 ms per loop
sage: timeit('test2(100000,R)')
5 loops, best of 3: 146 ms per loop
}}}
you see that `getattr` is consistently faster in looking up the attribute,
and also how expensive it is to fail to find it. Other variants using
`PyObject_GetAttr` etc. were a little slower still.
--
Ticket URL: <http://trac.sagemath.org/ticket/9885#comment:8>
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