Likelihood function given inverse link of f.

        .. math::
            p(y_{i}|\\lambda(f_{i})) = \\lambda(f_{i})^{y_{i}}(1-f_{i})^{1-y_{i}}

        :param inv_link_f: latent variables inverse link of f.
        :type inv_link_f: Nx1 array
        :param y: data
        :type y: Nx1 array
        :param Y_metadata: Y_metadata must contain 'trials'
        :returns: likelihood evaluated for this point
        :rtype: float

        .. Note:
            Each y_i must be in {0, 1}

def pdf_link(self, inv_link_f, y, Y_metadata):
        """
        Likelihood function given inverse link of f.

        .. math::
            p(y_{i}|\\lambda(f_{i})) = \\lambda(f_{i})^{y_{i}}(1-f_{i})^{1-y_{i}}

        :param inv_link_f: latent variables inverse link of f.
        :type inv_link_f: Nx1 array
        :param y: data
        :type y: Nx1 array
        :param Y_metadata: Y_metadata must contain 'trials'
        :returns: likelihood evaluated for this point
        :rtype: float

        .. Note:
            Each y_i must be in {0, 1}
        """
        return np.exp(self.logpdf_link(inv_link_f, y, Y_metadata))