create() [1/2]

GBComputation * GBDeclared::create ( const Matrix * leadterms, const Matrix * m, const Matrix * gb, const Matrix * change, const Matrix * syz )

static

Definition at line 117 of file comp-gb-declared.cpp.

{
  // Check:
  //   the rings are all the same, and all are not NULL.
  //   m->rows(), gb->rows() are the same
  //   change->rows(), syz->rows() are the same.
  assert(leadterms != 0 && m != 0 && gb != 0 && change != 0 && syz != 0);
  const Ring *R = gb->get_ring();
  if (R != m->get_ring() || R != leadterms->get_ring() ||
      R != change->get_ring() || R != syz->get_ring())
    {
      ERROR("expected the same ring");
      return nullptr;
    }
 
  const PolynomialRing *P = R->cast_to_PolynomialRing();
  if (P == nullptr)
    {
      ERROR("declaring a GB requires a polynomial ring");
      return nullptr;
    }
  if (leadterms->n_rows() != gb->n_rows() ||
      leadterms->n_cols() != gb->n_cols())
    {
      ERROR(
          "expected same number of lead terms as marked Groebner basis "
          "elements");
      return nullptr;
    }
  // Then: create and return the object
  return new GBDeclared(leadterms, m, gb, change, syz);
}

References Ring::cast_to_PolynomialRing(), ERROR, gb(), GBComputation::GBComputation(), GBDeclared(), Matrix::get_ring(), Matrix, Matrix::n_cols(), Matrix::n_rows(), and syz.