get_terms()

ring_elem PolyRing::get_terms ( int nvars0, const ring_elem f, int lo, int hi ) const

virtual

Implements PolynomialRing.

Definition at line 1919 of file poly.cpp.

{
  int nterms = n_logical_terms(nvars0, f);
  if (lo < 0) lo = nterms + lo;
  if (hi < 0) hi = nterms + hi;
 
  Nterm *t = f;
  if (t == nullptr) return t;
  Nterm head;
  Nterm *result = &head;
 
  exponents_t exp1 = newarray_atomic(int, n_vars());
  exponents_t exp2 = newarray_atomic(int, n_vars());
  M_->to_expvector(t->monom, exp1);
  int n = 0;
  while (t != nullptr)
    {
      if (n > hi) break;
      if (n >= lo)
        {
          result->next = copy_term(t);
          result = result->next;
        }
      t = t->next;
      if (t == nullptr) break;
      M_->to_expvector(t->monom, exp2);
      if (EQ == exponents::lex_compare(nvars0, exp1, exp2)) continue;
      exponents_t temp = exp1;
      exp1 = exp2;
      exp2 = temp;
      n++;
    }
  result->next = nullptr;
  return head.next;
}

References copy_term(), EQ, ExponentVector< int, true >::lex_compare(), PolynomialRing::M_, Nterm::monom, n_logical_terms(), PolynomialRing::n_vars(), newarray_atomic, Nterm::next, and result().