checkThreshold()

bool LLLoperations::checkThreshold ( ring_elem num, ring_elem den )

staticprivate

Definition at line 10 of file LLL.cpp.

{
  // Makes sure that 1/4 < num/den <= 1
  // Assumed: num, den are elements of ZZ.
  mpz_srcptr a = num.get_mpz();
  mpz_srcptr b = den.get_mpz();
  if (mpz_sgn(a) < 0) return false;
  if (mpz_sgn(b) < 0) return false;
  if (mpz_cmp(a, b) > 0) return false;  // return false if a>b.
  mpz_t c;
  mpz_init(c);
  mpz_mul_2exp(c, a, 2);  // c = 4*a
  int cmp = mpz_cmp(b, c);
  mpz_clear(c);
  if (cmp >= 0) return false;
  return true;
}

References ring_elem::get_mpz().

Referenced by initializeLLL().