division_in_place_monic()

TowerPolynomial DPoly::division_in_place_monic	(	int	level,
		TowerPolynomial &	f,
		const TowerPolynomial	g )

Definition at line 966 of file dpoly.cpp.

{
  // ASSUMPTION: g is MONIC, non-zero
  if (f == nullptr) return nullptr;
  if (f->deg < g->deg)
    {
      return nullptr;
    }
  int shift = f->deg - g->deg;
  TowerPolynomial quot = alloc_poly_n(shift);
 
  if (level == 0)
    {
      long *p = f->arr.ints;
      long *q = g->arr.ints;
      for (int d = f->deg; shift >= 0; d--, shift--)
        {
          long a = p[d];
          if (a != 0)
            {
              quot->arr.ints[shift] = a;
              ZZp_NEGATE(charac, a);
              for (int j = 0; j <= g->deg; j++)
                ZZp_APXY(charac, p[shift + j], a, q[j]);
            }
        }
      reset_degree_0(f);
    }
  else
    {
      TowerPolynomial *p = f->arr.polys;
      TowerPolynomial *q = g->arr.polys;
      for (int d = f->deg; shift >= 0; d--, shift--)
        {
          TowerPolynomial a = p[d];
          if (a != nullptr)
            {
              quot->arr.polys[shift] = copy(level - 1, a);
              for (int j = 0; j <= g->deg; j++)
                {
                  TowerPolynomial b = mult(level - 1, a, q[j], true);
                  subtract_in_place(level - 1, p[j + shift], b);
                }
            }
        }
      reset_degree_n(level, f);
    }
  return quot;
}

References alloc_poly_n(), charac, copy(), mult(), p, reset_degree_0(), reset_degree_n(), subtract_in_place(), ZZp_APXY(), and ZZp_NEGATE().

Referenced by gcd_coefficients().