3^k performance
"Ruud H.G. van Tol" <[email protected]>
| Newsgroups | gmane.comp.mathematics.pari.devel |
|---|---|
| Message-ID | <[email protected]> |
A022330_1(n)=1+n+sum(k=1,n,logint(3^k,2)) A022330_2(n)=my(t=1);1+n+sum(k=1,n,logint(t*=3,2)) ? A022330_1(10^5) cpu time = 8,322 ms, real time = 8,352 ms. %15 = 7924941755 ? A022330_2(10^5) cpu time = 215 ms, real time = 217 ms. %16 = 7924941755 So about a 40x difference. Is that worthwhile to look into? How to best approach that? BTW, I learned the trick from https://oeis.org/A071521 (Charles R Greathouse IV, 2018) -- Ruud P.S. And on pari-users I would probably have also asked which sumnum it should use. :)