cln::divisors()

[Ralf Stephan]

The complete factor() patch was sent to Richy.
Should the divisors be sorted?
Do we leave that to the client?
Can someone tell me why gcc barfs when I declare f const?

vector<cl_I> divisors(const cl_I& n)
{
  cl_FEV f = factor(n);
  vector<long> v(f.size());
  vector<cl_I> res;
  res.push_back(1);
  while (true)
  {
    vector<long>::iterator vit = v.begin();
    cl_FEV::iterator fit = f.begin();
    while (*vit == (*fit)->exp)
    { 
      *vit = 0; 
      if (++vit == v.end())
        return res; 
      ++fit; 
    }
    cl_I prod = expt_pos((*fit)->fact, ++(*vit));
    ++vit;
    ++fit;
    while (vit != v.end())
    {
      if (*vit > 0)
        prod = prod * expt_pos((*fit)->fact, *vit);
      ++vit;
      ++fit;
    }
    res.push_back(prod);
  }
}

ralf