2009-05-20, 11:25 | #1 |
Feb 2007
211 Posts |
What is Legendre Symbol? slowing down sr2sieve?
Recently i tried to sieve 22 K pairs with 1 < n < 50k small range. I used srsieve to sieve upto 1 BIL (approx 50 min) and the file it created sr_2.abcd
i tried using SR2Sieve but the load time for 194000 remaining N values is approx 50 min. It does something like "Building Legendre symbol lookup table for ________ each k value" and it is already utilizing 1.3 GB of memory Here are the K values i am working on. Code:
175977945*2^n-1 178140105*2^n-1 199140045*2^n-1 228461805*2^n-1 228986175*2^n-1 240924255*2^n-1 244133175*2^n-1 249671565*2^n-1 272605245*2^n-1 272936235*2^n-1 281804985*2^n-1 384158775*2^n-1 418791945*2^n-1 445419975*2^n-1 555567045*2^n-1 682980375*2^n-1 687218805*2^n-1 719053335*2^n-1 776668035*2^n-1 828512685*2^n-1 857996205*2^n-1 949473525*2^n-1 In the past i have sieve almost 100's of riesel K with 2 million + n (with sr2sieve) values and it never took such a long time to load or so much memory. Is there any way i can turn of "Building Legendre symbol " step. Thanks cipher |
2009-05-20, 11:46 | #2 |
Mar 2006
Germany
3^{2}·5^{2}·13 Posts |
turn off the calculation for Legendre symbol tables by option '-x'
or create a cache-file to compute this tables only once: '-C chache.dat' |
2009-05-20, 11:58 | #3 |
Feb 2003
2^{2}×3^{2}×53 Posts |
As Karsten already suggested:
Just turn off the computation of the Legendre symbols by using the "-x" switch. However, if you're planning larger n-ranges (e.g. up to 500k or 1M), then it might be useful to store the Legendre symbols in a cache file, as sr2sieve runs slightly faster with them... Good luck! |
2009-05-20, 13:35 | #4 |
Feb 2007
211 Posts |
if i turn it off using -x switch it runs 20% slower. I guess smart thing to do is to save it, using -c cache.dat
thanks cipher |
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