lead_monom()

EngineMonomial * RingElement::lead_monom

(

int

nvars

)

const

Definition at line 197 of file relem.cpp.

{
  if (is_zero())
    {
      ERROR("the zero element has no lead monomial");
      return nullptr;
    }
  const PolynomialRing *P = R->cast_to_PolynomialRing();
  if (P != nullptr)
    {
      gc_vector<int> resultvp;
      Nterm *t = get_value();
 
      exponents_t exp = newarray_atomic(int, nvars);
      P->lead_logical_exponents(nvars, t, exp);
      varpower::from_expvector(nvars, exp, resultvp);
      return EngineMonomial::make(resultvp.data());
    }
  const M2FreeAlgebraOrQuotient* Q = dynamic_cast<const M2FreeAlgebraOrQuotient*>(R);
  if (Q != nullptr)
    {
      ERROR("not implemented yet");
      return nullptr;
    }
  ERROR("expected polynomial ring");
  return nullptr;
}

References ERROR, ExponentList< int, true >::from_expvector(), get_value(), is_zero(), PolynomialRing::lead_logical_exponents(), EngineMonomial::make(), newarray_atomic, and R.

Referenced by IM2_RingElement_lead_monomial().