solve() [1/4]

bool Lapack::solve ( const DMatCC * A, const DMatCC * b, DMatCC * x )

static

Definition at line 1180 of file lapack.cpp.

{
  bool ret = true;
  int size = static_cast<int>(A->numRows());
  int bsize = static_cast<int>(b->numColumns());
  int info;
 
  /* make sure matrix is square */
  if (size != static_cast<int>(A->numColumns()))
    {
      ERROR("expected a square matrix");
      return false;
    }
 
  /* make sure dimensions of b make sense for Ax=b */
  if (b->numRows() != size)
    {
      ERROR("expected matrices to have same number of rows");
      return false;
    }
 
  if (size == 0)
    {
      x->resize(size, bsize);
      return true;
    }
 
  int* permutation = new int[size]; // TODO: set to 0?
  std::vector<double> copyA = make_lapack_array(*A);
  std::vector<double> copyb = make_lapack_array(*b);
 
  zgesv_(&size, &bsize, copyA.data(), &size, permutation, copyb.data(), &size, &info);
 
  if (info > 0)
    {
      ERROR("according to zgesv, matrix is singular");
      ret = false;
    }
  else if (info < 0)
    {
      ERROR("argument passed to zgesv had an illegal value");
      ret = false;
    }
  else
    {
      x->resize(size, bsize);
      fill_from_lapack_array(copyb, *x);
    }
 
  delete [] permutation;
  return ret;
}

References ERROR, fill_from_lapack_array(), make_lapack_array(), DMat< ACoeffRing >::numColumns(), DMat< ACoeffRing >::numRows(), x, and zgesv_().