intersect() [1/2]

MonomialIdeal * MonomialIdeal::intersect

(

const MonomialIdeal &

J

)

const

Definition at line 668 of file monideal.cpp.

{
  // The idea: take the elements of 'this'
  //   for each: if the element is in J, then keep it directly.
  //      otherwie compute the lcm's.
  VECTOR(Bag*) new_elems;
  for (Bag& a : *this)
    {
      Bag *c;
      if (J.search(a.monom().data(), c))
        {
          new_elems.push_back(new Bag(a));
        }
      else
        for (Bag& b : J)
          {
            Bag *new_elem = new Bag(a.basis_elem());
            varpower::lcm(a.monom().data(),
                          b.monom().data(),
                          new_elem->monom());
            new_elems.push_back(new_elem);
          }
    }
  MonomialIdeal *result = new MonomialIdeal(get_ring(), new_elems);
  GC_reachable_here(&J);
  return result;
}

References int_bag::basis_elem(), get_ring(), ExponentList< int, true >::lcm(), int_bag::monom(), MonomialIdeal(), result(), search(), and VECTOR.