#渋谷java あなたと乱数生成とJava

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

8. None

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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