R"""
    Autoregressive lognormal log-likelihood.

    .. math::
        x_i & = a_i \exp(e_i) \\
        e_i & = \rho e_{i-1} + \epsilon_i

    where :math:`\epsilon_i \sim N(0,\sigma)`.

def arlognormal_like(x, a, sigma, rho):
    R"""
    Autoregressive lognormal log-likelihood.

    .. math::
        x_i & = a_i \exp(e_i) \\
        e_i & = \rho e_{i-1} + \epsilon_i

    where :math:`\epsilon_i \sim N(0,\sigma)`.
    """
    return flib.arlognormal(x, np.log(a), sigma, rho, beta=1)