On Dec 1, 2009, at 10:02 AM, Martin Albrecht wrote:
> Hi there,
>
> the following code is really, really really (REALLY!) slow:
>
> sage: IP = InfinitePolynomialRing(QQ)
> sage: x = IP.gen()
> sage: x10000 = x[10000]
> sage: %time 1/2*x10000
> CPU times: user 0.86 s, sys: 0.00 s, total: 0.86 s
> Wall time: 0.87 s
> 1/2*x10000
Ouch, that is pretty bad. Looks like something changed in 4.2, it's
doing a huge amount of regular expressions stuff...
sage: %prun 1/2*x10000
160277 function calls in 1.002 CPU seconds
Ordered by: internal time
ncalls tottime percall cumtime percall filename:lineno(function)
2 0.719 0.359 1.000 0.500
infinite_polynomial_ring.py:595(__getitem__)
20002 0.133 0.000 0.189 0.000 {built-in method sub}
20002 0.047 0.000 0.059 0.000 re.py:229(_compile)
20002 0.033 0.000 0.281 0.000 re.py:144(sub)
20002 0.028 0.000 0.056 0.000 re.py:271(_subx)
20002 0.019 0.000 0.028 0.000 re.py:251(_compile_repl)
40004 0.016 0.000 0.016 0.000 {method 'get' of 'dict'
objects}
20018 0.006 0.000 0.006 0.000 {isinstance}
1 0.001 0.001 1.002 1.002 <string>:1(<module>)
5 0.000 0.000 0.000 0.000
infinite_polynomial_element.py:1053(__init__)
1 0.000 0.000 0.000 0.000
infinite_polynomial_element.py:1151(_add_)
- Robert
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