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: CBIG_hMRF_adapt_tau.m
    path of file: ./repos/CBIG/stable_projects/brain_parcellation/Yan2023_homotopic/code/step2_generate_parcellation/lib
    
    the code of the file until where you have to start completion: function [likelihood, results, label] = CBIG_hMRF_adapt_tau(params, label, full_corr_mat, lh_mask, rh_mask,...
    avg_mesh, Neighborhood, Smooth_cost, tau, i, likelihood, results)
% [likelihood, results, label] = CBIG_hMRF_adapt_tau(params, label, full_corr_mat, lh_mask, rh_mask,...
% avg_mesh, Neighborho
    
function tau_mod = update_tau_vector(label, tau, params, avg_mesh, lh_mask, rh_mask, max_vertices_in_an_island)
% this function checks the existence of split parcels, then update tau for these specific parcels.
% for parcels that are split into a main component (>3 vertices) and an island (<=3 vertices), 
% we shall not increase tau for the parcel.
% for parcels that have more than 2 components (expected to be very unlikeli), and increase tau by more folds.

lh_label = label(1:sum(lh_mask));
rh_label = label(sum(lh_mask)+1:end