Prime95 version 29.4

[Prime95]

Originally Posted by GP2

Would there be any speed advantage to using PRP base 2 over base 3?

No.

[Prime95]

Originally Posted by MrRepunit

Hi, I just noticed that the PRP test in prime95/mprime seems to be broken since version 29.4 (at least on Linux 64 Bit).

Fixed in next 29.5 build. The bug affected type-5 PRP tests with base != 2 and with known factors.

[kriesel]

Same i7-8750H Win10 x64 system that crashes or stalls in prime95 v29.5b5 benchmark, also does in prime95 x64 v29.4b8 benchmark after several rounds at 2304k.This system is 2 weeks old.

[MrRepunit]

Originally Posted by Prime95

Fixed in next 29.5 build. The bug affected type-5 PRP tests with base != 2 and with known factors.

Perfect, thank you very much.
When do you think the binary is available?

[GP2]

Originally Posted by MrRepunit

Perfect, thank you very much.
When do you think the binary is available?

But your base-10 repunit project uses type 1 residues, so fixing the type-5 bug won't affect your work.

The real reason to wait is because there is no Gerbicz error checking for repunits other than Mersenne and Wagstaff, so it's better to wait a while until the memory corruption issues with 29.5 beta are definitely ironed out. Although if you restrict to using only one or two cores, there doesn't seem to be a problem.

By the way, for everyone else reading this, the (eventual) discovery of a new record base-10 repunit prime could certainly grab the public's imagination, and it's easier to explain than Mersenne primes. As in "11 is prime, but 111 = 3 × 37, 11111 = 41 × 271, etc. You have to go up to 19 ones to get the next prime. The largest known (probable) prime of this form has 270,343 ones..." The search for the next one has reached nearly 4 million ones without success.

Maybe the Primenet infrastructure could be leveraged to also host Wagstaff or repunit-10 sister projects? Just a thought.

[James Heinrich]

Originally Posted by GP2

...discovery of a new record base-10 repunit prime could certainly grab the public's imagination

I think you overestimate the general public's interest in numbers.

[GP2]

Originally Posted by James Heinrich

I think you overestimate the general public's interest in numbers.

And yet we still issue press releases when a new Mersenne prime is found...

We're the thinking person's clickbait.

[axn]

Originally Posted by GP2

We're the thinking person's clickbait.

New slogan for GIMPS?

[MrRepunit]

Originally Posted by GP2

But your base-10 repunit project uses type 1 residues, so fixing the type-5 bug won't affect your work.

I know, I was just hoping to be able to use the json output which holds more information.

Originally Posted by GP2

The real reason to wait is because there is no Gerbicz error checking for repunits other than Mersenne and Wagstaff, so it's better to wait a while until the memory corruption issues with 29.5 beta are definitely ironed out. Although if you restrict to using only one or two cores, there doesn't seem to be a problem.

I did not follow the full thread, I should do it at some point. What I already asked if the Gerbicz test was going to be implemented once, see https://www.mersenneforum.org/showth...966#post468966.

So I want to ask again user Prime95:
What is the reason for not implementing it for other bases other that +/-2? I think the adaptions for other bases should not be too complicated, I derived it myself for base 10. But there might be some specific implementation details that would make it too complicated.

[Prime95]

Originally Posted by MrRepunit

What is the reason for not implementing it for other bases other that +/-2? I think the adaptions for other bases should not be too complicated

It is my understanding that Gerbicz error check only works base base 2

[axn]

Originally Posted by MrRepunit

So I want to ask again user Prime95:
What is the reason for not implementing it for other bases other that +/-2? I think the adaptions for other bases should not be too complicated, I derived it myself for base 10. But there might be some specific implementation details that would make it too complicated.

Originally Posted by Prime95

It is my understanding that Gerbicz error check only works base base 2

GEC can be made to work for any base. But the efficient "squaring-only" computation sequence works only for base 2. For other bases, you will have mul mods as well, which will increase the run times significantly (about 50% ?). Of course, it still might be worth it, if you were planning on doublechecking your work (which you can dispense with when using GEC).