rawARingGaloisField()

const Ring * rawARingGaloisField	(	int	prime,
		int	dimension )

Todo

why parameters are ints and not longs or mpz's? is an overflow possible?

check prime for primality (probably at top of Macaulay2)

ARingGFGivaro uses tables and may consume a huge amount of memory - pass therefore a 'MaxMemoryConsumption' parameter and if the value is overstepped by ARingGFGivaro, create polynomial representation?

the check if in general polynomial representation is needed cost some additional work, similar to linbox/field/givaro-gfq.h. Use GivaroGfq instead of Givaro::GFqDom in ARingGFGivaro?

Todo

return Macaulay Galois field in some cases.

Definition at line 138 of file aring.cpp.

{
  if (dimension < 0)
    {
      ERROR(" givaroGF/FFPACK: help, dimension is negative ! ");
      return nullptr;
    }
  try
    {
#if 1
 
      if (prime <= 1)
        {
          ERROR("givaroGF/FFPACK: expected a prime number p ");
          return nullptr;
        }
 
      //-- NEED_POLYNOMIAL_REPRESENTATION is not usable(namespace problems) and
      // is not correct, because the answer depends on the template used for
      // Givaro::GFqDom.
      /*if (Givaro::NEED_POLYNOMIAL_REPRESENTATION(prime,dimension) )
      {
          ERROR("givaro Galois Field: polynomial representation is needed  -
      todo ");
          return 0;
      }*/
      if (dimension == 1 && M2::ARingZZpFFPACK::getMaxModulus() > prime)
        {
          // std::cout << "maximum modulus = " <<
          // M2::ARingZZpFFPACK::getMaxModulus() << std::endl;
          return M2::ConcreteRing<M2::ARingZZpFFPACK>::create(prime);
        }
      if (dimension == 1)
        {
          ERROR("maximum modulus = %f\n", M2::ARingZZpFFPACK::getMaxModulus());
          return nullptr;
        }
      #if 0
      return M2::ConcreteRing<M2::ARingGFGivaro>::create(prime, dimension);
      #endif
      ERROR("calling rawARingGaloisField with no longer allowed values, givaro is no longer available");
      return nullptr;
#else
      ERROR("add --enable-fflas-ffpack --enable-givaro when building M2");
      return 0;
#endif
  } catch (const exc::engine_error& e)
    {
      ERROR(e.what());
      return nullptr;
  }
}

References M2::ConcreteRing< RingType >::create(), ERROR, and M2::ARingZZpFFPACK::getMaxModulus().