def init_standard_poly(result, x, pos, cur_var):
    """Initialize the first order before starting the recursion.

    .. note::

        An init function also returns some indices relevant to further
        steps in which the recursion formula is applied. The
        first index indicates where the recursion is applied first.
        In the case of standard polynomials this is *pos+1*.
        The second index indicates the order of the element on which
        the recursion is applied first. In the case of standard polynomials
        this order is equal to 2. The third index specifies the index
        of a special member for use in the recursion. This might be a
        constant order element that is used in every recursion. In the case
        of standard polynomials this can be *pos* (as this is where *x* is) or
        None (as *x* is passed to the recursion anyway).


    Mathematically this amounts to
    P_1 = x.

    :param result: Contains the observations along the first dimension
        and the function values of expansion w.r.t. an observation
        along the second dimension.
    :type result: numpy.ndarray

    :param x: The data to be expanded.
    :type x: numpy.ndarray

    :param pos: The index of the element to be computed, along the second
        dimension of result.
    :type int: int

    :param cur_var: The index of the current variable to be considered in the
        recursion. This value will have to be lower than x.shape[1].
    :type cur_var: int

    :returns: The index of the next element that will be computed in the
        recursion, the order of the next element, and the index of a special
        element.
    :rtype: Tuple[int, int, int]
    """
    result[:, (pos)] = x[:, (cur_var)]
    return pos + 1, 2, pos
