Signature Matrix and Minhash Values Quiz

What does the signature matrix represent?

Columns as sets and rows as minhash values

What should be consistent in assigning minhash values?

It doesn't matter

What does the expected similarity of two signatures equal to?

The Jaccard similarity of the columns they represent

How does the text define the probability that h(C1) = h(C2)?

Equal to a certain value a/(a+b+c)! Signup and view all the answers

In the context of signatures, what does Jaccard similarity measure?

The fraction of minhash functions in which they agree Signup and view all the answers

Why does it not matter whether the minhash value is the original row number or in permuted order?

To ensure consistency and correctness Signup and view all the answers

What is the formula provided in the text to calculate the probability of sharing a bucket?

1 - (1 - s^r)^b Signup and view all the answers

In the context of finding similar pairs with similar signatures, what is the significance of tuning 'b' and 'r'?

To eliminate most pairs with similar signatures Signup and view all the answers

What does the value 's' represent in the given context?

Jaccard similarity of two sets Signup and view all the answers

When finding similar pairs based on Jaccard similarity, what does it mean for 'all rows of a band' to be equal?

Both pairs have identical elements in each row Signup and view all the answers

What was the real problem faced by the student who ran a MOOC based on CS246 in the fall?

Searching for similar pairs among a large number of sets Signup and view all the answers

If a user wants to find almost all pairs with similar signatures but eliminate most pairs without similar signatures, what strategy should they adopt?

Tune 'b' and 'r' appropriately Signup and view all the answers

What is the formula for calculating Jaccard similarity between two sets?

|C1C2|/|C1C2| Signup and view all the answers

If two sets have 3 elements in common and a union of 8 elements, what is their Jaccard similarity?

0.375 Signup and view all the answers

What is the warning given regarding constructing the matrix for Jaccard similarity calculations?

The matrix doesn't need to be physically constructed. Signup and view all the answers

What does the minhash function h(C) represent in the context of Jaccard similarity?

The index of the first row with '1' in a permuted order. Signup and view all the answers

What does the formula Sim(C1, C2) = a/(a + b + c) represent?

Jaccard similarity calculation between C1 and C2. Signup and view all the answers

Why do we apply several randomly chosen permutations to create signatures for each column in Jaccard similarity calculations?

To create a unique representation for each column. Signup and view all the answers