brandt
/ bloom-filter-calculator.rb
Created
February 17, 2015 17:19
Calculate the required bloom filter size and optimal number of hashes from the expected number of items in the collection and acceptable false-positive rate
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| # Optimal bloom filter size and number of hashes | |
| # Tips: | |
| # 1. One byte per item in the input set gives about a 2% false positive rate. | |
| # 2. The optimal number of hash functions is ~0.7x the number of bits per item. | |
| # 3. The number of hashes dominates performance. | |
| # Expected number of items in the collection | |
| # n = (m * ln(2))/k; | |
| n = 300_000 |