# Calculating Similarity between two multiset

I need to find similarity between two multiset. For example,

$$A = \{a, a, b, c, d\}$$ $$B = \{a, b, b, d\}$$

I know that I can use Jaccard Index but it gives same weight for each element. As element a has occurred two times in A so I want to put extra weight on it.

So, In this case, what's the best algorithm or formula for calculating the similarity?

• Please try first to search Jaccard similarity on the site. There are 5 or so potentially helpful or hintful questions. – ttnphns Sep 15 '17 at 14:01
• Top five.......? – Atish Dipongkor - MVP Sep 15 '17 at 17:23
• It's hard to answer this question without a clear objective in mind. What application is this for? – Alex R. Sep 15 '17 at 17:24
• May I know what are the options here? – Atish Dipongkor - MVP Sep 15 '17 at 19:14