def cho_solve_ATAI(A, rho, b, c, lwr, check_finite=True):
    r"""
    Solve the linear system :math:`(A^T A + \rho I)\mathbf{x} = \mathbf{b}`
    or :math:`(A^T A + \rho I)X = B` using :func:`scipy.linalg.cho_solve`.

    Parameters
    ----------
    A : array_like
      Matrix :math:`A`
    rho : float
      Scalar :math:`\rho`
    b : array_like
      Vector :math:`\mathbf{b}` or matrix :math:`B`
    c : array_like
      Matrix containing lower or upper triangular Cholesky factor,
      as returned by :func:`scipy.linalg.cho_factor`
    lwr : bool
      Flag indicating whether the factor is lower or upper triangular

    Returns
    -------
    x : ndarray
      Solution to the linear system
    """

    N, M = A.shape
    if N >= M:
        x = linalg.cho_solve((c, lwr), b, check_finite=check_finite)
    else:
        x = (b - A.T.dot(linalg.cho_solve((c, lwr), A.dot(b),
                                          check_finite=check_finite))) / rho
    return x
r"""
    Solve the linear system :math:`(A^T A + \rho I)\mathbf{x} = \mathbf{b}`
    or :math:`(A^T A + \rho I)X = B` using :func:`scipy.linalg.cho_solve`.

    Parameters
    ----------
    A : array_like
      Matrix :math:`A`
    rho : float
      Scalar :math:`\rho`
    b : array_like
      Vector :math:`\mathbf{b}` or matrix :math:`B`
    c : array_like
      Matrix containing lower or upper triangular Cholesky factor,
      as returned by :func:`scipy.linalg.cho_factor`
    lwr : bool
      Flag indicating whether the factor is lower or upper triangular

    Returns
    -------
    x : ndarray
      Solution to the linear system