#1305 - gp core() function: could do better?

PARI/GP Bug report logs - #1305
gp core() function: could do better?

Reported by: Kevin Buzzard <k.buzzard@imperial.ac.uk>

Date: Mon, 19 Mar 2012 11:18:16 UTC

Severity: normal

Done: Karim Belabas <Karim.Belabas@math.u-bordeaux1.fr>

Bug is archived. No further changes may be made.

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From: Kevin Buzzard <k.buzzard@imperial.ac.uk>
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Subject: gp core() function: could do better?
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Package: pari-stable Version: 2.5.0 [Sorry -- I should upgrade to 2.5.1, but I didn't yet, and I don't see core mentioned in the changelog 2.5.0->2.5.1 so let me gamble that this is still an issue] What do you think of this? (11:00) gp > isprime(10^1000+1) %1 = 0 (11:00) gp > core(5*(10^1000+1)^2) [gp now goes into a very long loop, presumably because it's trying to factor (10^1000+1)^2?] I am not C++-savvy enough to know what the "core" function was doing in 2.5.0, but in this particular case I can see a relatively simple way of spotting the answer: if we use trial division or ECM or whatever to find a few small factors, then could it be worth checking to see if what we have left is a square?? If it is then we're done. Presumably core() is not currently doing this... Kevin

Bill Allombert <allomber@math.u-bordeaux.fr>. Last modified: Sat Aug 26 17:05:00 2023; Machine Name: pari

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PARI/GP Bug report logs - #1305 gp core() function: could do better?

PARI/GP Bug report logs - #1305
gp core() function: could do better?