PFGW latest well-tested version

[MyDogBuster]

While running PFGW 3.2.2 standalone (not wirh PRPNet) using this parameter:

ABC $a*3^$b+1 // {number_primes,$a,1}

The program did skip any subsequent tests for any k's found until I had to ctrl-c out. When I restarted the run, the checkpoint worked just fine BUT tests for any found k's were not being skipped. I fixed it by stopping the run again and inserting the PRP tests for the found k's after the checkpoint. Skipping resumed again for those k's. Shouldn't the program read the pfgw.log file (if present) when restarting to get those k's?

[Flatlander]

It's a known 'quirk'.
http://mersenneforum.org/showpost.ph...6&postcount=13
Last paragraph.

[MyDogBuster]

It's a known 'quirk'.
http://mersenneforum.org/showpost.ph...6&postcount=13
Last paragraph.

Thanks Chris. It's only real bad news when running a large file expecting to find many primes. I actually thought it was easier to repeat the PRP tests to get the skipping working again. All I have to do is cleanup the output file and remove the duplicate primes from pfgw.log.

[Flatlander]

Good idea. I think I'll do that in the future.

[Siemelink]

Another method would be to sort your file by k instead of n. When a prime/PRP is found this would skip the rest of this k right away. This may get confusing, as we usually track n, not k.

Cheers, Willem.

[gd_barnes]

I've updated the downloadable versions of PFGW in the 1st post here to version 3.2.3. Version 3.2.0 did not correct many of the roundoff errors. Apparently version 3.2.3 does. I'm testing the tough Riesel base 40 from n=1 to 1000 that had many roundoff errors in 3.2.0 to prove it.


Gary

[gd_barnes]

Originally Posted by gd_barnes

I've updated the downloadable versions of PFGW in the 1st post here to version 3.2.3. Version 3.2.0 did not correct many of the roundoff errors. Apparently version 3.2.3 does. I'm testing the tough Riesel base 40 from n=1 to 1000 that had many roundoff errors in 3.2.0 to prove it.


Gary

I figured I should provide an update here. I've now tested 1000's of k's on Sierp bases 35, 39, and 40 to n=2500 or n=10K and only encountered one roundoff error. PFGW 3.2.3 is working very well!

[Flatlander]

Were the timings the same?

[gd_barnes]

I didn't check but I have no reason to think there would be any significant difference.

[PCZ]

3.2.3 hasn't completely eliminated the roundoff errors.
Ran a few base 7 numbers with pfgw 3.2.3 and got this

-----------------------------------------------------------------------
Error occuring in PFGW at Wed Nov 25 18:13:03 2009
Expr = 7370*7^250081-1
Detected in MAXERR>0.45 (round off check) in prp_using_gwnum
Iteration: 506787/702078 ERROR: ROUND OFF 0.5>0.45

(Test aborted, try again using the -a1 switch)

Ony tested about 10 pairs or so i don't know how frequently this error would occur.

[rogue]

Originally Posted by PCZ

3.2.3 hasn't completely eliminated the roundoff errors.
Ran a few base 7 numbers with pfgw 3.2.3 and got this

-----------------------------------------------------------------------
Error occuring in PFGW at Wed Nov 25 18:13:03 2009
Expr = 7370*7^250081-1
Detected in MAXERR>0.45 (round off check) in prp_using_gwnum
Iteration: 506787/702078 ERROR: ROUND OFF 0.5>0.45

(Test aborted, try again using the -a1 switch)

Ony tested about 10 pairs or so i don't know how frequently this error would occur.

If George (Prime95) reads this, he will probably address it in his next release of gwnum. These have become much rarer as George has really been on the ball to address them.