find_reduction_coeffs()

void GBRing::find_reduction_coeffs	(	const FreeModule *	F,
		const gbvector *	f,
		const gbvector *	g,
		ring_elem &	u,
		ring_elem &	v )

Definition at line 872 of file gbring.cpp.

{
  const ring_elem a = f->coeff;
  const ring_elem b = g->coeff;
  K->syzygy(a, b, u, v);  // If possible, u==1, anyway, u>0
 
  if (is_skew_commutative())
    {
      exponents_t EXP1 = ALLOCATE_EXPONENTS(exp_size);
      exponents_t EXP2 = ALLOCATE_EXPONENTS(exp_size);
      exponents_t EXP3 = ALLOCATE_EXPONENTS(exp_size);
      gbvector_get_lead_exponents(F, f, EXP1);  // Removes the Schreyer part
      gbvector_get_lead_exponents(F, g, EXP2);  // Removes the Schreyer part
      divide_exponents(EXP1, EXP2, EXP3);
      if (_skew.mult_sign(EXP3, EXP2) < 0) K->negate_to(v);
    }
}

References _skew, ALLOCATE_EXPONENTS, gbvector::coeff, divide_exponents(), exp_size, gbvector_get_lead_exponents(), is_skew_commutative(), and K.

Referenced by gbvector_reduce_lead_term(), gbvector_reduce_with_marked_lead_term(), and reduce_marked_lead_term_heap().