SIFT in matlab using vl_sift function
<p>I am using vl_sift(from vl_feat site)function for finding SIFT descriptor, which is giving me descriptor of size 128*1 for one image and 128*2 for the second. I got the reason behind 128 but I am not getting why the columns keep changing(sometimes 1 and sometimes 2),it has to be same right?  Can anyone explain me what does those columns represents?
Thank you </p>