You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: rvmRegFp.m
    path of file: ./repos/PRMLT/chapter07
    
    the code of the file until where you have to start completion: function [model, llh] = rvmRegFp(X, t, alpha, beta)
% Relevance Vector Machine (ARD sparse prior) for regression
% training by empirical bayesian (type II ML) using Mackay fix point update.
% Input:

    
function [model, llh] = rvmRegFp(X, t, alpha, beta)
% Relevance Vector Machine (ARD sparse prior) for regression
% training by empirical bayesian (type II ML) using Mackay fix point update.
% Input:
%   X: d x n data
%   t: 1 x n response
%   alpha: prior parameter
%   beta: prior parameter
% Output:
%   model: trained model structure
%   llh: loglikelihood
% Written by Mo Chen (sth4nth@gmail.com).
if nargin < 3
    alpha = 0.02;
    beta = 0.5;
end