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Old 2008-12-11, 04:34   #12
Kosmaj
 
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Nov 2003

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And you have a level of arrogance approaching infinity

Code:
b=5684341886080801486968994140701;
n=2481892977737648921240994084183;
p=3433683820292512484657849089373;

m=1;while(n>0,if(n%2>0,m=(m*b)%p);b=(b*b)%p;n=n>>1);

m=1721733593148639177176135185028
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Old 2008-12-11, 04:57   #13
CRGreathouse
 
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Sure, though
Code:
lift(Mod(b,p)^n)
would actually be faster for n large enough to matter.
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Old 2008-12-11, 05:23   #14
gd_barnes
 
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Quote:
Originally Posted by henryzz View Post
what is the crossover point is it 3 ks or more or does it depend on the size of the k or something else

In my experience, use sr2sieve for 3 k's or more, regardless of the size or nature of the k-value. Use 1 or 2 instances of sr1sieve for 1 or 2 k's. I believe the k-value must be > 2^n where n is the lowest n-value being sieved, although I think that restriction also exists in NewPGen.

I haven't done any testing with exotic forms but I'm confident that this is the fastest way for the standard k*2^n-1 and +1 forms. In no case is NewPGen more efficient for these forms.

Keep in mind that you have to run srsieve first to get a "starting file" before using its output file as input to sr1sieve or sr2sieve. I generally use srsieve to sieve to P=250M, 500M, or 1G before changing over.

Once you get used to running them at the command prompt instead of using the GUI like NewPGen has, it's child's play to use them.


Gary

Last fiddled with by gd_barnes on 2008-12-11 at 05:26
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Old 2008-12-11, 05:32   #15
mdettweiler
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Quote:
Originally Posted by gd_barnes View Post
I believe the k-value must be > 2^n where n is the lowest n-value being sieved, although I think that restriction also exists in NewPGen.
Um...I presume you mean that the k-value must be *less than* 2^n, not greater?
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Old 2008-12-11, 07:43   #16
henryzz
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Quote:
Originally Posted by gd_barnes View Post
In my experience, use sr2sieve for 3 k's or more, regardless of the size or nature of the k-value. Use 1 or 2 instances of sr1sieve for 1 or 2 k's. I believe the k-value must be > 2^n where n is the lowest n-value being sieved, although I think that restriction also exists in NewPGen.

I haven't done any testing with exotic forms but I'm confident that this is the fastest way for the standard k*2^n-1 and +1 forms. In no case is NewPGen more efficient for these forms.

Keep in mind that you have to run srsieve first to get a "starting file" before using its output file as input to sr1sieve or sr2sieve. I generally use srsieve to sieve to P=250M, 500M, or 1G before changing over.

Once you get used to running them at the command prompt instead of using the GUI like NewPGen has, it's child's play to use them.


Gary
thanks that was what i suspected
i have used srsieve and sr1sieve for a bit but i have never used sr2sieve although i should be able to work it out when i need to
i usually work on ks in pairs so i have been using sr1sieve
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Old 2008-12-11, 11:46   #17
Flatlander
I quite division it
 
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Feb 2005
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Quote:
Originally Posted by henryzz View Post
thanks that was what i suspected
i have used srsieve and sr1sieve for a bit but i have never used sr2sieve although i should be able to work it out when i need to
i usually work on ks in pairs so i have been using sr1sieve
Well, I still find it confusing but here's a link I still refer to:
http://mersenneforum.org/showpost.ph...9&postcount=67

( I think you can ignore the cache sizes parameters and reference to Core(). )
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