Re: integer n-roots like sqrtint()

Jeroen Demeyer on Tue, 05 Feb 2008 08:47:03 +0100

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Re: integer n-roots like sqrtint()

To: pari-users <pari-users@list.cr.yp.to>
Subject: Re: integer n-roots like sqrtint()
From: Jeroen Demeyer <jdemeyer@cage.ugent.be>
Date: Tue, 05 Feb 2008 08:31:27 +0100
Delivery-date: Tue, 05 Feb 2008 08:47:03 +0100
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Karim Belabas wrote:

Yes, since perfect powers are the bad case, you could use

  if (!ispower(x, n, &z), z = floor(sqrtn(x, n)));
  z;

Yes, I guess that works (at least if the realprecision is sufficientlyhigh).

I'm wondering if this can be considered a bug in PARI. Do you think itmakes sense to change the implementation of sqrtn() to first callispower() when the argument is an exact integer?

Cheers,
Jeroen.

Follow-Ups:
- Re: integer n-roots like sqrtint()
  - From: Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>

References:
- integer n-roots like sqrtint()
  - From: Jeroen Demeyer <jdemeyer@cage.ugent.be>
- Re: integer n-roots like sqrtint()
  - From: Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>
- Re: integer n-roots like sqrtint()
  - From: Karim Belabas <Karim.Belabas@math.u-bordeaux1.fr>

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