= "https://www.mathworks.com/matlabcentral/fileexchange/22940-vol3d-v2"><span style=' text-decoration: underline;'>vol3d</span></a><span> in </span><a href = "https://github.com/villekf/OMEGA/blob/master/visualize_pet.m#L344"><span style=' text-decoration: underline;'>visualize_pet.m</span></a><span>.</span></div><div  class = 'S4'><span>For random subset sampling (</span><span style=' font-family: monospace;'>subset_type = 3</span><span>), it is recommended to use </span><a href = "https://www.mathworks.co