Just random approximations sometimes useful in work for "mental" calculation.
b(p) ≈ 1.44 * log₂(p)
b
— bits per elementp
— false positive probability
p | b |
---|---|
5.0% | 6 |
2.0% | 8 |
1.0% | 10 |
0.5% | 11 |
0.1% | 14 |
p(n, d) ≈ 1 - exp(-n² / 2d)
p
— colision probabilityn
— number of elementsd
— "days", space size
Only for stable systems!
L = λ * W
L
— long-term average numberλ
— average arrival rateW
— average processing time