s += 0.5 * (fast_logdet(sigma_) + n_samples * log(alpha_)
                                                                coef_[keep_lambda] = alpha_ * np.dot(
 sigma_, np.dot(X[:, keep_lambda].T, y))
 coef_[keep_lambda] = alpha_ * np.dot(
     sigma_, np.dot(X[:, keep_lambda].T, y))