C++ (Cpp) Float::pow_si Examples

Example #1

File: test_svp.cpp Project: damons/fplll

/**
   @brief Compute the norm of a dual vector (specified by coefficients in the dual basis).

   @param A              input lattice
   @param b              coefficients of shortest dual vector
   @return
*/
template <class ZT> int dual_length(Float &norm, ZZ_mat<ZT> &A, const IntVect &coords)
{
  int d = coords.size();
  if (A.get_rows() != d)
  {
    cerr << "DSVP length error: Coefficient vector has wrong dimension: ";
    cerr << A.get_rows() << " vs " << d << endl;
    return 1;
  }
  FloatVect coords_d(d);
  for (int i = 0; i < d; i++)
  {
    coords_d[i] = coords[i].get_d();
  }

  IntMatrix empty_mat;
  MatGSO<Integer, Float> gso(A, empty_mat, empty_mat, GSO_INT_GRAM);
  if (!gso.update_gso())
  {
    cerr << "GSO Failure." << endl;
    return 1;
  }
  Float tmp;
  gso.get_r(tmp, d - 1, d - 1);
  tmp.pow_si(tmp, -1);

  FloatVect alpha(d);
  Float mu, alpha2, r_inv;
  norm = 0.0;
  for (int i = 0; i < d; i++)
  {
    alpha[i] = coords_d[i];
    for (int j = 0; j < i; j++)
    {
      gso.get_mu(mu, i, j);
      alpha[i] -= mu * alpha[j];
    }
    gso.get_r(r_inv, i, i);
    r_inv.pow_si(r_inv, -1);
    alpha2.pow_si(alpha[i], 2);
    norm += alpha2 * r_inv;
  }

  return 0;
}