- **GPU to 72**
(*https://www.mersenneforum.org/forumdisplay.php?f=95*)

- - **Double Checking on GPU72**
(*https://www.mersenneforum.org/showthread.php?t=18982*)

[QUOTE=davieddy;362776]I feel a prime coming on:smile:[/QUOTE]
That would be quite a shock. :shock: |

[QUOTE=kladner;362788]That would be quite a shock. :shock:[/QUOTE]
Probability per day = (tests per day)*(probability of error)/250,000 |

[QUOTE=davieddy;362790]Probability per day = (tests per day)*(probability of error)/250,000[/QUOTE]Isn't there a factor missing: Namely the probability of a number being prime.
Probability per day = (tests per day)*(probability of error)/250,000 [color=red]* probability of being prime[/color] [size=1][sup][sup][sup][sup][sup]Why is the colour tag missing the u?[/sup][/sup][/sup][/sup][/sup][/size] |

[QUOTE=retina;362857]Isn't there a factor missing: Namely the probability of a number being prime.
Probability per day = (tests per day)*(probability of error)/250,000 [COLOR=red]* probability of being prime[/COLOR] [SIZE=1][sup][sup][sup][sup][sup]Why is the colour tag missing the u?[/sup][/sup][/sup][/sup][/sup][/SIZE][/QUOTE] No. What requires clarification is the LHS. It is the probability of a shock, namely finding a prime. As it stands it refers to Kieren's DCs. For my LL it would be (1/50)/450,000. Merry Christmas! |

[QUOTE=retina;362857]Isn't there a factor missing: Namely the probability of a number being prime.
Probability per day = (tests per day)*(probability of error)/250,000 [color=red]* probability of being prime[/color] [/QUOTE] What is the role of the magic number "1/250000"? Also, it is not "Probability per day", it is "Expected primes per day" (as in, with really large values, the result can easily be > 1) |

[QUOTE=axn;362861]Also, it is not "Probability per day", it is "Expected primes per day" (as in, with really large values, the result can easily be > 1)[/QUOTE]
THX. An important distinction. The expected primes per day for the whole project is 1/1500. So the probability of one or more primes per day is 1 - e[SUP]=1/1500[/SUP] = 1/1500.5 :smile: |

[QUOTE=davieddy;362866]The expected primes per day for the whole project is 1/1500.
So the probability of one or more primes per day is 1 - e[SUP]=1/1500[/SUP] = 1/1500.5[/QUOTE] @Phil: THX for allowing me to participate in the sort of mathsy fun which I enjoy. Perhaps the 0.5 is worth looking into: 1 - e[SUP]-1/X[/SUP] ~ 1/X - 0.5*(1/X)[SUP]2[/SUP] = (1/X)*(1 - 0.5*(1/X)) ~ 1/(X*(1 + 0.5*(1/X)) = 1/(X + 0.5) Wish I had done it that way first time. Damn those calculators:smile: D |

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