## Question on speed

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• I created a program that is testing for potential primes at 10^1,000,000,000+. My test yesterday was from 10^1,000,000,000 to 10^1,000,000,000+1,000,000 it
Message 1 of 4 , Jan 13, 2007
I created a program that is testing for potential primes at 10^1,000,000,000+.
My test yesterday was from 10^1,000,000,000 to 10^1,000,000,000+1,000,000
it took 9 minutes and 5 seconds to run the test. I was able to eliminate all but 9112 as being prime. That is using a small prime library of primes up to 1,000,000 approx.
Just to make sure it is clear that is 10 to the 1 billion. Got a lot of questions about that on another forum.

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• ... From the speed, I can only assume you re running on a programmable calculator, or a PDA. NewPGen, which is notoriously inefficient for the initial ramp-up
Message 2 of 4 , Jan 13, 2007
--- george hayes <gr.hayes@...> wrote:
> I created a program that is testing for potential primes at
> 10^1,000,000,000+.
> My test yesterday was from 10^1,000,000,000 to 10^1,000,000,000+1,000,000
> it took 9 minutes and 5 seconds to run the test. I was able to eliminate
> all but 9112 as being prime. That is using a small prime library of primes up
> to 1,000,000 approx.
> Just to make sure it is clear that is 10 to the 1 billion. Got a lot of
> questions about that on another forum.

From the speed, I can only assume you're running on a programmable calculator,
or a PDA. NewPGen, which is notoriously inefficient for the initial ramp-up of
tiny primes can get to about 2 million in only a few seconds.

And from your sieving depth, I'd have thought that about 72000 candidates
should remain, so it sounds as if you have a bug.

Phil
Phil

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• ... He says that he is doing billion-digit primes.
Message 3 of 4 , Jan 13, 2007
At 02:36 PM 1/13/2007, Phil Carmody wrote:

>--- george hayes <<mailto:gr.hayes%40yahoo.com>gr.hayes@...> wrote:
> > I created a program that is testing for potential primes at
> > 10^1,000,000,000+.
> > My test yesterday was from 10^1,000,000,000 to 10^1,000,000,000+1,000,000
> > it took 9 minutes and 5 seconds to run the test. I was able to eliminate
> > all but 9112 as being prime. That is using a small prime library
> of primes up
> > to 1,000,000 approx.
> > Just to make sure it is clear that is 10 to the 1 billion. Got a lot of
> > questions about that on another forum.
>
> From the speed, I can only assume you're running on a programmable
> calculator,

He says that he is doing billion-digit primes.
• ... No, potential primes . I can do that instantly by doing nothing. However, if I wanted to make use of a small prime library of primes up to 1,000,000
Message 4 of 4 , Jan 13, 2007
--- Jud McCranie <j.mccranie@...> wrote:
> At 02:36 PM 1/13/2007, Phil Carmody wrote:
> >--- george hayes <<mailto:gr.hayes%40yahoo.com>gr.hayes@...> wrote:
> > > I created a program that is testing for potential primes at
> > > 10^1,000,000,000+.
> > > My test yesterday was from 10^1,000,000,000 to 10^1,000,000,000+1,000,000
> > > it took 9 minutes and 5 seconds to run the test. I was able to eliminate
> > > all but 9112 as being prime. That is using a small prime library
> > of primes up
> > > to 1,000,000 approx.
> > > Just to make sure it is clear that is 10 to the 1 billion. Got a lot of
> > > questions about that on another forum.
> >
> > From the speed, I can only assume you're running on a programmable
> > calculator,
>
> He says that he is doing billion-digit primes.

No, 'potential primes'. I can do that instantly by doing nothing.

However, if I wanted to make use of a "small prime library of primes up to
1,000,000 approx.", then I'd probably sieve the range with that the, and I'd
take something more comparable to a second than ten minutes.

There's less than one thousandth of a prime in that range, and certainly zero
provable ones even if there's one probable-prime.

Phil

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