#渋谷java あなたと乱数生成とJava

第十回 #渋谷java http://shibuya-java.connpass.com/event/11574/ での発表資料です。Java で乱数生成するときのお話をしました。

Transcript

1. ͋ͳͨͱཚ਺ੜ੒ͱ Java ୈेճ #ौ୩java 2015-03-07 @komiya_atsushi
2. ͓·ͩΕ ʢ͓લ୭Αʁʣ
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5. Ad server and machine learning with Java
6. Random Number Generator
7. java.util.Random
9. Random classes provided by JDK
10. Random classes provided by JDK • java.util.Random • java.security.SecureRandom • SecureRandom.getInstance("SHA1PRNG")   • java.util.concurrent.ThreadLocalRandom • ThreadLocalRandom.current()
11. Random classes provided by commons-math3
12. Random classes provided by commons-math3 • MersenneTwister • most popular (?) random number generator • Well44497a • longer period than Mersenne Twister • ISAACRandom • a fast cryptographic pseudo-random number generator
13. Random classes provided by commons-math3 • RandomDataGenerator supports sampling from various distributions • Beta / Binomial / Cauchy / ChiSquare / Exponential / F / Gamma / Hypergeometric / Pascal / Poisson / T / Weibull / Zipf • java.util.Random only supports sampling from Gaussian (normal distribution)
14. Comparisons
15. Concurrency of Random and ThreadLocalRandom
16. Concurrency of Random and ThreadLocalRandom 5ISFBE-PDBM3BOEPN
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17. Latency of 200,000,000 times random number generation
18. Latency of 200,000,000 times random number generation .FSTFOOF5XJTUFS
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19. Conclusion
20. If you need… • high concurrency one • use ThreadLocalRandom • very long-period & high quality one • use Well44497a • long-period & fast one • use MersenneTwister • cryptographically secure one • use SecureRandom
21. Thanks! Any questions?
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    PS
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