list_form()

engine_RawArrayPairOrNull PolyRing::list_form ( const Ring * coeffR, const ring_elem f ) const

virtual

Implements PolynomialRing.

Definition at line 1789 of file poly.cpp.

{
  // Either coeffR should be the actual coefficient ring (possible a "toField"ed
  // ring)
  // or a polynomial ring.  If not, NULL is returned and an error given
  // In the latter case, the last set of variables are part of
  // the coefficients.
  int nvars0 = check_coeff_ring(coeffR, this);
  if (nvars0 < 0) return nullptr;
  int n = n_logical_terms(nvars0, f);
  engine_RawMonomialArray monoms =
      GETMEM(engine_RawMonomialArray, sizeofarray(monoms, n));
  engine_RawRingElementArray coeffs =
      GETMEM(engine_RawRingElementArray, sizeofarray(coeffs, n));
  monoms->len = n;
  coeffs->len = n;
  engine_RawArrayPair result = newitem(struct engine_RawArrayPair_struct);
  result->monoms = monoms;
  result->coeffs = coeffs;
 
  exponents_t exp = newarray_atomic(int, n_vars());
  gc_vector<int> resultvp;
  const Nterm *t = f;
  for (int next = 0; next < n; next++)
    {
      getMonoid()->to_expvector(t->monom, exp);
      ring_elem c =
          get_logical_coeff(coeffR, t);  // increments t to the next term of f.
      varpower::from_expvector(nvars0, exp, resultvp);
      monoms->array[next] = EngineMonomial::make(resultvp.data());
      coeffs->array[next] = RingElement::make_raw(coeffR, c);
      resultvp.resize(0);
 
      assert(monoms->array[next] != NULL);
      assert(coeffs->array[next] != NULL);
    }
  freemem(exp);
  return result;
}

References check_coeff_ring(), freemem(), ExponentList< int, true >::from_expvector(), get_logical_coeff(), GETMEM, PolynomialRing::getMonoid(), EngineMonomial::make(), RingElement::make_raw(), Nterm::monom, n_logical_terms(), PolynomialRing::n_vars(), newarray_atomic, newitem, result(), Ring::Ring(), sizeofarray, and Monoid::to_expvector().