|Bill Allombert on Tue, 05 Feb 2008 10:41:09 +0100|
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|Re: integer n-roots like sqrtint()|
On Tue, Feb 05, 2008 at 08:31:27AM +0100, Jeroen Demeyer wrote: > 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 sufficiently > high). > > I'm wondering if this can be considered a bug in PARI. Do you think it Well, sqrtn could be slightly more accurate since 6. is exactly representable. > makes sense to change the implementation of sqrtn() to first call > ispower() when the argument is an exact integer? If we improve sqrtn accuracy we should do it for all input, not just perfect powers. Cheers, Bill.