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Old 2014-06-27, 16:16   #1
tcharron
 
Jan 2013

111002 Posts
Default GHZ-days calculation Q

Here are three recent TF results...
Code:
Exponent    Result    Received            age     Result                    GHz-Days
334455661    NF    2014-06-27 15:33    0.0    no factor from 2^68 to 2^69    0.1787
334455061    NF    2014-06-27 15:29    0.0    no factor from 2^67 to 2^68    0.0894
106292027    NF    2014-06-27 15:22    1.8    no factor from 2^67 to 2^68    0.2812
Why are the larger exponents getting less credit than the smallest one? Not sure why it might matter, but the larger ones were from an i7, and the smaller ones on an older xeon.
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Old 2014-06-27, 16:25   #2
firejuggler
 
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Factor of mersenne numbers are in the form of 2*k*p+1
P is the exponent, k is a *random* number

Between 2^67 and 2^68, there is more (2* 106292027* k)+1 multiple than (2*334455061 *k)+1
so, there is more work, therefore more credit.
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Old 2014-06-27, 16:27   #3
LaurV
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Factors q of mersenne numbers m are of the form q=2kp+1, where m=2^p-1. Technically, if p is bigger, you have less candidates to test, between 2^x and 2^(x+1). Imagine you have to find prime numbers of the form 11*something+1, and 13*something+1, between 2^15 and 2^16. Which are more?
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Old 2014-06-27, 17:50   #4
tcharron
 
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Doh! Makes perfect sense...
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Old 2014-06-27, 23:27   #5
swl551
 
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Here is the formula for calculating TF GHZdz

GHZdz=28.50624 * (Math.Pow(2, to - 47) - Math.Pow(2, from - 47)) / exp
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