Function id_SimpleAdd

libpolys/polys/simpleideals.cc:789–827

concat the lists h1 and h2 without zeros

/// concat the lists h1 and h2 without zeros
ideal id_SimpleAdd (ideal h1,ideal h2, const ring R)
{
  id_Test(h1, R);
  id_Test(h2, R);

  if ( idIs0(h1) )
  {
    ideal res=id_Copy(h2,R);
    if (res->rank<h1->rank) res->rank=h1->rank;
    return res;
  }
  if ( idIs0(h2) )
  {
    ideal res=id_Copy(h1,R);
    if (res->rank<h2->rank) res->rank=h2->rank;
    return res;
  }

  int j = IDELEMS(h1)-1;
  while ((j >= 0) && (h1->m[j] == NULL)) j--;

  int i = IDELEMS(h2)-1;
  while ((i >= 0) && (h2->m[i] == NULL)) i--;

  const int r = si_max(h1->rank, h2->rank);

  ideal result = idInit(i+j+2,r);

  int l;

  for (l=j; l>=0; l--)
    result->m[l] = p_Copy(h1->m[l],R);

  j = i+j+1;
  for (l=i; l>=0; l--, j--)
    result->m[j] = p_Copy(h2->m[l],R);

  return result;
}

/// insert h2 into h1 (if h2 is not the zero polynomial)
/// return TRUE iff h2 was indeed inserted