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-   -   Verification of Feitsma's psp(2) data (https://www.mersenneforum.org/showthread.php?t=26649)

Happy5214 2021-03-29 10:41

Verification of Feitsma's psp(2) data
 
I have no idea if this is the right place to post this, so someone can move it if necessary. Did Cleaver and Gilchrist, or anyone else for that matter, ever finish the independent verification of Jan Feitsma's base 2 pseudoprime data? [URL="http://www.janfeitsma.nl/math/psp2/verification"]Feitsma's page on the verification status[/URL] hasn't been updated since April 2013, and it only shows the Wieferich verification as having been completed by that time.

CRGreathouse 2021-03-30 01:59

[QUOTE=Happy5214;574717]Did Cleaver and Gilchrist, or anyone else for that matter, ever finish the independent verification of Jan Feitsma's base 2 pseudoprime data?[/QUOTE]

I believe they each verified this independently back in 2010 (maybe 2009). When I say "independently", I mean that they wrote software implementations independently of each other -- they used the same underlying mathematics, so that's still a potential source of error for those concerned about correctness.

And many people, myself included, checked that there were no BPSW pseudoprimes on the list.

Jeff Gilchrist 2021-03-31 09:47

David Cleaver and I are actually re-doing the verification again in hopes of better documenting what we did so we can publish the results. That is ongoing right now, no ETA when that will be finished yet.

Happy5214 2021-03-31 11:27

[QUOTE=Jeff Gilchrist;574834]David Cleaver and I are actually re-doing the verification again in hopes of better documenting what we did so we can publish the results. That is ongoing right now, no ETA when that will be finished yet.[/QUOTE]
Good to know. I'll be keeping an eye out for that.

WraithX 2021-03-31 11:42

[QUOTE=CRGreathouse;574771]I believe they each verified this independently back in 2010 (maybe 2009). When I say "independently", I mean that they wrote software implementations independently of each other -- they used the same underlying mathematics, so that's still a potential source of error for those concerned about correctness.

And many people, myself included, checked that there were no BPSW pseudoprimes on the list.[/QUOTE]

And to make it a little more clear, Jan wrote his code and built his database a long time ago.

Then I coded up the underlying algorithms and Jeff and I ran that code in a coordinated effort to create our own database to compare to Jan's database. Jeff also helped update this code so it could run on his computers back in the day. But, I know I've lost some of my data since then, so we couldn't verify how much of this work we had done.

As Jeff mentioned, we are redoing the verification. I've re-written the code, with a big thanks to Ben Buhrow for providing low level mul-mod and factorization code!, and this is what Jeff and I are currently using to redo the verification. And, to second what Jeff said, the work is ongoing and there's no ETA for when we'll be finished.

pinhodecarlos 2021-03-31 12:36

Happy to help out under Windows,16 GB,(4C/8T).


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