#5415: problems with multifactorial?
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Reporter: cwitty | Owner: robertwb
Type: defect | Status: needs_info
Priority: major | Milestone: sage-6.10
Component: basic arithmetic | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps: todo
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Comment (by nbruin):
Replying to [comment:17 prateek.cs14]:
> Thanks nbruin.
> Please review the changes made.
>
https://github.com/prateekcs14/sage/commit/2cb944378c97bdad76a053e37d579d492f68d44c
Currently, the code was nicely interruptable with CTRL-C if a particularly
long computation was being done. Does your code have that property? (hint:
no, because you stripped out the `sig_on/sig_off`)
Currently, the code was taking efforts to balance the size of the factors
it was multiplying. This is a well-known technique to improve performance,
because it reduces the number of multiplications where a particularly big
number is involved (currently there is a 32/64 bit bug in that code, by
the way) You strip that out. Do you have data to confirm this is not a
problem?
You may want to try things like
{{{
sage: %timeit 10000001.multifactorial(2)
1 loops, best of 3: 8.47 s per loop
}}}
and possibly with larger numbers too. You should compare the current
implementation with the new one.
--
Ticket URL: <http://trac.sagemath.org/ticket/5415#comment:18>
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