#5652: powermod is slower than Integer.power_mod
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Reporter: bober | Owner: somebody
Type: defect | Status: new
Priority: minor | Milestone: sage-3.4.2
Component: basic arithmetic | Keywords:
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Consider the following example:
{{{
sage: time a = power_mod(5, 10^2000, 10^3000)
CPU times: user 3.67 s, sys: 0.00 s, total: 3.67 s
Wall time: 3.67 s
sage: time b = 5.powermod(10^2000, 10^3000)
CPU times: user 2.82 s, sys: 0.00 s, total: 2.83 s
Wall time: 2.84 s
sage: a == b
True
sage: time a = power_mod(5, 10^4000, 10^7000)
CPU times: user 27.17 s, sys: 0.01 s, total: 27.18 s
Wall time: 27.30 s
sage: time b = 5.powermod(10^4000, 10^7000)
CPU times: user 21.38 s, sys: 0.04 s, total: 21.42 s
Wall time: 21.44 s
sage: a == b
True
}}}
(The problem is that power_mod() uses generic code, while
Integer.powermod() uses gmp, which is faster.)
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/5652>
Sage <http://sagemath.org/>
Sage - Open Source Mathematical Software: Building the Car Instead of
Reinventing the Wheel
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