bodr...@mail.dm.unipi.it writes: > I propose > mp_bitcnt_t mpz_perfect_root (mpz_t root, const mpz_t x, mp_bitcnt_t nth); > > If nth != 0, check if x is a perfect nth-root (generalize perfect_square). > If nth == 0, search for a non-trivial relation root^e = x, and return e.
Both variants make sense, but I'm not sure they should be the same function. > To be coherent, the return value e should always be the exponent, such > that root^e = x. I.e. when only the trivial equation x^1 = x exists, > return 1 and set root=x. > > I'm not sure I'd vote for coherence in this particular case. I think it's desirable that mpz_perfect_power_p can be re-implemented by a call to new new function followed by a very simple check on the return value. Then we need distinct return values for the case |x| <= 1 (which are considered perfect powers) and non-powers. Using 1 for the former and 0 for the latter seems like a reasonable choice to me. Regards, /Niels -- Niels Möller. PGP-encrypted email is preferred. Keyid C0B98E26. Internet email is subject to wholesale government surveillance. _______________________________________________ gmp-devel mailing list gmp-devel@gmplib.org http://gmplib.org/mailman/listinfo/gmp-devel
