Multiply shift — where it appears
Named by 2 essays across one field — each of them below, with the objects they name alongside it.
A hash is a family, not a function
Two thousand and forty-eight keys into two hundred and fifty-six buckets. Under a hash that takes the low bits of the key, all 2,048 land in bucket zero and 255 buckets are empty. Under a multiplier drawn at random, the worst bucket holds 11. The keys are the same keys, and they are the multiples of the table size.
Two hashes that shared their low bits
Two pages on blocked Bloom filters with thresholds each recorded an instability they could not explain: a false-positive rate that collapsed on one seed at 256-bit blocks, and a pair of four-bit thresholds measuring 0.169% where its neighbours measured 0.08%. Both came from how a hash was brought into range. Every filter took its block and its ordering value as a modulo of a multiply-shift hash, and the low bits of such a hash depend only on the low bits of the key, so the two values were dependent whenever the block count had a factor of two to spare. At 992 blocks the threshold filter measures anything from 0.185% to 0.645%; read from the hash's top bits, 0.126% to 0.133%.
Named alongside it
The objects these essays reach for when they reach for this one.
Bloom filterUniversal hashingAdversarial inputBlocked filterBucket loadClosed formDesign parameterFalse-positive rateGuaranteeHash familyHash functionHash table