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Old 2016-12-10, 07:50   #2
Batalov's Avatar
Mar 2008

25·3·101 Posts

The script will take care of everything. q values should not concern you; they will be variable for different runs and will depend on the project's complexity. Different sievers will be chosen by the script, too; their rate of sieving might seem sometimes logical to the untrained eye and sometimes unexpectedly slower (on the next project) - but you should trust the script.

Here are the fairly good rules of thumb:
- for SNFS, with every 9 additional digits of SNFS difficulty, the overall runtime will double (or, which is the same, runtime will be 10x for every 30 digits)
- for GNFS, with every 5 additional digits of length(N), the overall runtime will double

Remember just these two and you will be in good shape.

Examples: a 120-digit SNFS complexity project might take 1 core-hour on your computer. Then you can assume that a 150-digit SNFS complexity project will take 10 hours, a 180-digit SNFS complexity project will take 100 hours, and a 210-digit SNFS complexity project will take 1000 hours (~40 core-days). Ok?

You can estimate how hard a GNFS project will be by taking length of the input number N, and converting to (N-30)*1.8 = similarly hard SNFS complexity. For example, a 130-digit GNFS is approximately as hard as a 180-SNFS-digit difficulty SNFS (from the estimate above, ~100 core-hours).
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