power() [2/2]

ring_elem GF::power ( const ring_elem f, mpz_srcptr n ) const

virtual

Exponentiation. This is the default function, if a class doesn't define this.

Reimplemented from Ring.

Definition at line 397 of file GF.cpp.

{
  if (f.get_int() != _ZERO)
    {
      int exp = RingZZ::mod_ui(n, Q1_);
      int m = (f.get_int() * exp) % Q1_; // WARNING TODO: possible overflow! Check!
      if (m <= 0) m += Q1_;
      return ring_elem(m);
    }
  else
    {
      if (mpz_sgn(n) == 0)
        return ring_elem(_ONE);
      else if (mpz_sgn(n) > 0)
        return ring_elem(_ZERO);
      else
        throw exc::division_by_zero_error();
    }
}

References _ONE, _ZERO, ring_elem::get_int(), RingZZ::mod_ui(), and Q1_.

Referenced by promote().