def rosenbrock(params):
    """ Implement Rosenbrock function.

    Function description: https://www.sfu.ca/~ssurjano/rosen.html.

    Args:
        params (pandas.DataFrame): Must have the column "value" containing
        input values for parameters. Accepts arbitrary numbers of input values.

    Returns:
        integer:  Rosenbrock function output.

    """
    params_np = params["value"].to_numpy()
    r1 = ((params_np[1:] - params_np[:-1] ** 2) ** 2).sum() * 100
    r2 = ((params_np[:-1] - 1) ** 2).sum()
    return r1 + r2