C241 New Lanczos Time – 357 Hours

After advice from Serge Batalov, I stopped the Lanczos run on the 241-digit composite number and did five more days of sieving with GGNFS. This increased the raw relation count from about 102 M to nearly 116 M.

...
Fri Dec 18 17:45:40 2009  found 23488388 hash collisions in 115930392 relations
Fri Dec 18 17:45:55 2009  commencing duplicate removal, pass 2
Fri Dec 18 17:47:58 2009  found 23586813 duplicates and 92343579 unique relations
...

These extra relations enabled Msieve to reduce the matrix size from about 13.2 M down to about 11.3 M, thus considerably reducing the run-time for solution. Here is the reduced time estimate:

C241 New Lanczos Time

The new time in the Lanczos step saves 515 – 357 = 158 hours. The extra sieving took 5 days or 120 hours. That’s an overall saving of 38 hours — a grand total of a day and a half. 🙂

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