20090104, 10:36  #1 
Nov 2008
2322_{10} Posts 
Smaller filtering run oddity
This occurred when I was trying to factor 2^293309 with SNFS:
Code:
Sun Jan 4 10:04:30 2009 Sun Jan 4 10:04:30 2009 Sun Jan 4 10:04:30 2009 Msieve v. 1.39 Sun Jan 4 10:04:30 2009 random seeds: d5ad21b2 8ae26bdb Sun Jan 4 10:04:30 2009 factoring 15914343565113172548972231940698266883214596825515126958094847260581103904401068017057483 (89 digits) Sun Jan 4 10:04:32 2009 no P1/P+1/ECM available, skipping Sun Jan 4 10:04:32 2009 commencing number field sieve (89digit input) Sun Jan 4 10:04:32 2009 R0: 9444732965739290427392 Sun Jan 4 10:04:32 2009 R1: 1 Sun Jan 4 10:04:32 2009 A0: 309 Sun Jan 4 10:04:32 2009 A1: 0 Sun Jan 4 10:04:32 2009 A2: 0 Sun Jan 4 10:04:32 2009 A3: 0 Sun Jan 4 10:04:32 2009 A4: 2 Sun Jan 4 10:04:32 2009 skew 1.00, size 3.580988e09, alpha 1.471436, combined = 1.987871e09 Sun Jan 4 10:04:32 2009 Sun Jan 4 10:04:32 2009 commencing relation filtering Sun Jan 4 10:04:33 2009 commencing duplicate removal, pass 1 Sun Jan 4 10:04:46 2009 found 1352 hash collisions in 864685 relations Sun Jan 4 10:04:52 2009 added 141454 free relations Sun Jan 4 10:04:52 2009 commencing duplicate removal, pass 2 Sun Jan 4 10:04:55 2009 found 0 duplicates and 1006139 unique relations Sun Jan 4 10:04:55 2009 memory use: 36.1 MB Sun Jan 4 10:04:55 2009 reading rational ideals above 327680 Sun Jan 4 10:04:55 2009 reading algebraic ideals above 327680 Sun Jan 4 10:04:55 2009 commencing singleton removal, pass 1 Sun Jan 4 10:05:52 2009 relations with 0 large ideals: 31936 Sun Jan 4 10:05:55 2009 relations with 1 large ideals: 264933 Sun Jan 4 10:05:55 2009 relations with 2 large ideals: 549612 Sun Jan 4 10:05:55 2009 relations with 3 large ideals: 21768 Sun Jan 4 10:05:55 2009 relations with 4 large ideals: 9 Sun Jan 4 10:05:55 2009 relations with 5 large ideals: 137881 Sun Jan 4 10:05:56 2009 relations with 6 large ideals: 0 Sun Jan 4 10:05:56 2009 relations with 7+ large ideals: 0 Sun Jan 4 10:05:56 2009 1006139 relations and about 1372743 large ideals Sun Jan 4 10:05:56 2009 commencing singleton removal, pass 2 Sun Jan 4 10:06:49 2009 found 599136 singletons Sun Jan 4 10:07:01 2009 current dataset: 407003 relations and about 332990 large ideals Sun Jan 4 10:07:06 2009 commencing singleton removal, pass 3 Sun Jan 4 10:08:11 2009 found 177321 singletons Sun Jan 4 10:08:14 2009 current dataset: 229682 relations and about 134097 large ideals Sun Jan 4 10:08:20 2009 commencing singleton removal, final pass Sun Jan 4 10:08:49 2009 memory use: 9.8 MB Sun Jan 4 10:08:49 2009 commencing inmemory singleton removal Sun Jan 4 10:08:49 2009 begin with 229682 relations and 135225 unique ideals Sun Jan 4 10:08:49 2009 reduce to 190726 relations and 95041 ideals in 8 passes Sun Jan 4 10:08:49 2009 max relations containing the same ideal: 13 Sun Jan 4 10:08:50 2009 reading rational ideals above 163840 Sun Jan 4 10:08:50 2009 reading algebraic ideals above 163840 Sun Jan 4 10:08:50 2009 commencing singleton removal, final pass Sun Jan 4 10:09:01 2009 keeping 481651 ideals with weight <= 20, new excess is 31667 Sun Jan 4 10:09:02 2009 memory use: 15.3 MB Sun Jan 4 10:09:02 2009 commencing inmemory singleton removal Sun Jan 4 10:09:02 2009 begin with 263462 relations and 481651 unique ideals Sun Jan 4 10:09:03 2009 reduce to 188886 relations and 117764 ideals in 8 passes Sun Jan 4 10:09:03 2009 max relations containing the same ideal: 20 Sun Jan 4 10:09:03 2009 removing 59960 relations and 42766 ideals in 17194 cliques Sun Jan 4 10:09:03 2009 commencing inmemory singleton removal Sun Jan 4 10:09:03 2009 begin with 128926 relations and 117764 unique ideals Sun Jan 4 10:09:03 2009 reduce to 124735 relations and 70453 ideals in 5 passes Sun Jan 4 10:09:03 2009 max relations containing the same ideal: 17 Sun Jan 4 10:09:03 2009 removing 40562 relations and 23368 ideals in 17194 cliques Sun Jan 4 10:09:03 2009 commencing inmemory singleton removal Sun Jan 4 10:09:03 2009 begin with 84173 relations and 70453 unique ideals Sun Jan 4 10:09:03 2009 reduce to 78666 relations and 40735 ideals in 6 passes Sun Jan 4 10:09:03 2009 max relations containing the same ideal: 13 Sun Jan 4 10:09:03 2009 relations with 0 large ideals: 10285 Sun Jan 4 10:09:03 2009 relations with 1 large ideals: 29912 Sun Jan 4 10:09:03 2009 relations with 2 large ideals: 26323 Sun Jan 4 10:09:03 2009 relations with 3 large ideals: 9830 Sun Jan 4 10:09:03 2009 relations with 4 large ideals: 1724 Sun Jan 4 10:09:03 2009 relations with 5 large ideals: 589 Sun Jan 4 10:09:03 2009 relations with 6 large ideals: 3 Sun Jan 4 10:09:03 2009 relations with 7+ large ideals: 0 Sun Jan 4 10:09:03 2009 commencing 2way merge Sun Jan 4 10:09:04 2009 reduce to 57483 relation sets and 19552 unique ideals Sun Jan 4 10:09:04 2009 commencing full merge Sun Jan 4 10:09:04 2009 memory use: 1.6 MB Sun Jan 4 10:09:04 2009 found 37897 cycles, need 31867 Sun Jan 4 10:09:04 2009 weight of 31867 cycles is about 887091 (27.84/cycle) Sun Jan 4 10:09:04 2009 distribution of cycle lengths: Sun Jan 4 10:09:04 2009 1 relations: 10285 Sun Jan 4 10:09:04 2009 2 relations: 6462 Sun Jan 4 10:09:04 2009 3 relations: 4534 Sun Jan 4 10:09:04 2009 4 relations: 3538 Sun Jan 4 10:09:04 2009 5 relations: 2950 Sun Jan 4 10:09:04 2009 6 relations: 2158 Sun Jan 4 10:09:04 2009 7 relations: 1563 Sun Jan 4 10:09:04 2009 8 relations: 369 Sun Jan 4 10:09:04 2009 9 relations: 8 Sun Jan 4 10:09:04 2009 10+ relations: 0 Sun Jan 4 10:09:04 2009 heaviest cycle: 9 relations Sun Jan 4 10:09:04 2009 matrix not dense enough, retrying Sun Jan 4 10:09:05 2009 reading rational ideals above 131072 Sun Jan 4 10:09:05 2009 reading algebraic ideals above 131072 Sun Jan 4 10:09:05 2009 commencing singleton removal, final pass Sun Jan 4 10:09:16 2009 keeping 487187 ideals with weight <= 25, new excess is 26131 Sun Jan 4 10:09:17 2009 memory use: 15.3 MB Sun Jan 4 10:09:17 2009 commencing inmemory singleton removal Sun Jan 4 10:09:17 2009 begin with 263462 relations and 487187 unique ideals Sun Jan 4 10:09:17 2009 reduce to 188876 relations and 123290 ideals in 8 passes Sun Jan 4 10:09:17 2009 max relations containing the same ideal: 25 Sun Jan 4 10:09:17 2009 removing 60919 relations and 43282 ideals in 17637 cliques Sun Jan 4 10:09:18 2009 commencing inmemory singleton removal Sun Jan 4 10:09:18 2009 begin with 127957 relations and 123290 unique ideals Sun Jan 4 10:09:18 2009 reduce to 123437 relations and 75089 ideals in 5 passes Sun Jan 4 10:09:18 2009 max relations containing the same ideal: 19 Sun Jan 4 10:09:18 2009 removing 41505 relations and 23868 ideals in 17637 cliques Sun Jan 4 10:09:18 2009 commencing inmemory singleton removal Sun Jan 4 10:09:18 2009 begin with 81932 relations and 75089 unique ideals Sun Jan 4 10:09:18 2009 reduce to 75964 relations and 44324 ideals in 6 passes Sun Jan 4 10:09:18 2009 max relations containing the same ideal: 15 Sun Jan 4 10:09:18 2009 relations with 0 large ideals: 6815 Sun Jan 4 10:09:18 2009 relations with 1 large ideals: 22881 Sun Jan 4 10:09:18 2009 relations with 2 large ideals: 27008 Sun Jan 4 10:09:18 2009 relations with 3 large ideals: 14214 Sun Jan 4 10:09:18 2009 relations with 4 large ideals: 3773 Sun Jan 4 10:09:18 2009 relations with 5 large ideals: 1225 Sun Jan 4 10:09:18 2009 relations with 6 large ideals: 48 Sun Jan 4 10:09:18 2009 relations with 7+ large ideals: 0 Sun Jan 4 10:09:18 2009 commencing 2way merge Sun Jan 4 10:09:18 2009 reduce to 54876 relation sets and 23236 unique ideals Sun Jan 4 10:09:18 2009 commencing full merge Sun Jan 4 10:09:19 2009 memory use: 1.8 MB Sun Jan 4 10:09:19 2009 found 31039 cycles, need 26331 Sun Jan 4 10:09:19 2009 weight of 26331 cycles is about 1135175 (43.11/cycle) Sun Jan 4 10:09:19 2009 distribution of cycle lengths: Sun Jan 4 10:09:19 2009 1 relations: 6815 Sun Jan 4 10:09:19 2009 2 relations: 3743 Sun Jan 4 10:09:19 2009 3 relations: 2709 Sun Jan 4 10:09:19 2009 4 relations: 2263 Sun Jan 4 10:09:19 2009 5 relations: 2019 Sun Jan 4 10:09:19 2009 6 relations: 1727 Sun Jan 4 10:09:19 2009 7 relations: 1471 Sun Jan 4 10:09:19 2009 8 relations: 1317 Sun Jan 4 10:09:19 2009 9 relations: 1214 Sun Jan 4 10:09:19 2009 10+ relations: 3053 Sun Jan 4 10:09:19 2009 heaviest cycle: 15 relations Sun Jan 4 10:09:19 2009 matrix can improve, retrying Sun Jan 4 10:09:20 2009 reading rational ideals above 131072 Sun Jan 4 10:09:20 2009 reading algebraic ideals above 131072 Sun Jan 4 10:09:20 2009 commencing singleton removal, final pass Sun Jan 4 10:09:31 2009 keeping 487190 ideals with weight <= 30, new excess is 26128 Sun Jan 4 10:09:32 2009 memory use: 15.3 MB Sun Jan 4 10:09:32 2009 commencing inmemory singleton removal Sun Jan 4 10:09:32 2009 begin with 263462 relations and 487190 unique ideals Sun Jan 4 10:09:32 2009 reduce to 188876 relations and 123293 ideals in 8 passes Sun Jan 4 10:09:32 2009 max relations containing the same ideal: 29 Sun Jan 4 10:09:32 2009 removing 60919 relations and 43282 ideals in 17637 cliques Sun Jan 4 10:09:32 2009 commencing inmemory singleton removal Sun Jan 4 10:09:33 2009 begin with 127957 relations and 123293 unique ideals Sun Jan 4 10:09:33 2009 reduce to 123437 relations and 75092 ideals in 5 passes Sun Jan 4 10:09:33 2009 max relations containing the same ideal: 19 Sun Jan 4 10:09:33 2009 removing 41505 relations and 23868 ideals in 17637 cliques Sun Jan 4 10:09:33 2009 commencing inmemory singleton removal Sun Jan 4 10:09:33 2009 begin with 81932 relations and 75092 unique ideals Sun Jan 4 10:09:33 2009 reduce to 75964 relations and 44327 ideals in 6 passes Sun Jan 4 10:09:33 2009 max relations containing the same ideal: 15 Sun Jan 4 10:09:33 2009 relations with 0 large ideals: 6812 Sun Jan 4 10:09:33 2009 relations with 1 large ideals: 22875 Sun Jan 4 10:09:33 2009 relations with 2 large ideals: 27003 Sun Jan 4 10:09:33 2009 relations with 3 large ideals: 14225 Sun Jan 4 10:09:33 2009 relations with 4 large ideals: 3776 Sun Jan 4 10:09:33 2009 relations with 5 large ideals: 1224 Sun Jan 4 10:09:33 2009 relations with 6 large ideals: 49 Sun Jan 4 10:09:33 2009 relations with 7+ large ideals: 0 Sun Jan 4 10:09:33 2009 commencing 2way merge Sun Jan 4 10:09:33 2009 reduce to 54876 relation sets and 23239 unique ideals Sun Jan 4 10:09:33 2009 commencing full merge Sun Jan 4 10:09:34 2009 memory use: 1.8 MB Sun Jan 4 10:09:34 2009 found 31038 cycles, need 26328 Sun Jan 4 10:09:34 2009 weight of 26328 cycles is about 1135740 (43.14/cycle) Sun Jan 4 10:09:34 2009 distribution of cycle lengths: Sun Jan 4 10:09:34 2009 1 relations: 6812 Sun Jan 4 10:09:34 2009 2 relations: 3742 Sun Jan 4 10:09:34 2009 3 relations: 2707 Sun Jan 4 10:09:34 2009 4 relations: 2257 Sun Jan 4 10:09:34 2009 5 relations: 2018 Sun Jan 4 10:09:34 2009 6 relations: 1731 Sun Jan 4 10:09:34 2009 7 relations: 1471 Sun Jan 4 10:09:34 2009 8 relations: 1315 Sun Jan 4 10:09:34 2009 9 relations: 1219 Sun Jan 4 10:09:34 2009 10+ relations: 3056 Sun Jan 4 10:09:34 2009 heaviest cycle: 15 relations Sun Jan 4 10:09:34 2009 matrix can improve, retrying Sun Jan 4 10:09:34 2009 reading rational ideals above 131072 Sun Jan 4 10:09:34 2009 reading algebraic ideals above 131072 Sun Jan 4 10:09:34 2009 commencing singleton removal, final pass Sun Jan 4 10:09:46 2009 keeping 487192 ideals with weight <= 35, new excess is 26126 Sun Jan 4 10:09:47 2009 memory use: 15.3 MB Sun Jan 4 10:09:47 2009 commencing inmemory singleton removal Sun Jan 4 10:09:47 2009 begin with 263462 relations and 487192 unique ideals Sun Jan 4 10:09:47 2009 reduce to 188876 relations and 123295 ideals in 8 passes Sun Jan 4 10:09:47 2009 max relations containing the same ideal: 33 Sun Jan 4 10:09:47 2009 removing 60919 relations and 43282 ideals in 17637 cliques Sun Jan 4 10:09:47 2009 commencing inmemory singleton removal Sun Jan 4 10:09:47 2009 begin with 127957 relations and 123295 unique ideals Sun Jan 4 10:09:48 2009 reduce to 123437 relations and 75094 ideals in 5 passes Sun Jan 4 10:09:48 2009 max relations containing the same ideal: 22 Sun Jan 4 10:09:48 2009 removing 41505 relations and 23868 ideals in 17637 cliques Sun Jan 4 10:09:48 2009 commencing inmemory singleton removal Sun Jan 4 10:09:48 2009 begin with 81932 relations and 75094 unique ideals Sun Jan 4 10:09:48 2009 reduce to 75964 relations and 44329 ideals in 6 passes Sun Jan 4 10:09:48 2009 max relations containing the same ideal: 15 Sun Jan 4 10:09:48 2009 relations with 0 large ideals: 6810 Sun Jan 4 10:09:48 2009 relations with 1 large ideals: 22866 Sun Jan 4 10:09:48 2009 relations with 2 large ideals: 27008 Sun Jan 4 10:09:48 2009 relations with 3 large ideals: 14230 Sun Jan 4 10:09:48 2009 relations with 4 large ideals: 3774 Sun Jan 4 10:09:48 2009 relations with 5 large ideals: 1226 Sun Jan 4 10:09:48 2009 relations with 6 large ideals: 50 Sun Jan 4 10:09:48 2009 relations with 7+ large ideals: 0 Sun Jan 4 10:09:48 2009 commencing 2way merge Sun Jan 4 10:09:48 2009 reduce to 54876 relation sets and 23241 unique ideals Sun Jan 4 10:09:48 2009 commencing full merge Sun Jan 4 10:09:49 2009 memory use: 1.8 MB Sun Jan 4 10:09:49 2009 found 31035 cycles, need 26326 Sun Jan 4 10:09:49 2009 weight of 26326 cycles is about 1135958 (43.15/cycle) Sun Jan 4 10:09:49 2009 distribution of cycle lengths: Sun Jan 4 10:09:49 2009 1 relations: 6810 Sun Jan 4 10:09:49 2009 2 relations: 3741 Sun Jan 4 10:09:49 2009 3 relations: 2705 Sun Jan 4 10:09:49 2009 4 relations: 2256 Sun Jan 4 10:09:49 2009 5 relations: 2021 Sun Jan 4 10:09:49 2009 6 relations: 1728 Sun Jan 4 10:09:49 2009 7 relations: 1471 Sun Jan 4 10:09:49 2009 8 relations: 1316 Sun Jan 4 10:09:49 2009 9 relations: 1219 Sun Jan 4 10:09:49 2009 10+ relations: 3059 Sun Jan 4 10:09:49 2009 heaviest cycle: 15 relations Sun Jan 4 10:09:49 2009 matrix can improve, retrying Sun Jan 4 10:09:49 2009 reading rational ideals above 131072 Sun Jan 4 10:09:49 2009 reading algebraic ideals above 131072 Sun Jan 4 10:09:49 2009 commencing singleton removal, final pass Sun Jan 4 10:10:01 2009 keeping 487195 ideals with weight <= 40, new excess is 26123 Sun Jan 4 10:10:02 2009 memory use: 15.3 MB Sun Jan 4 10:10:02 2009 commencing inmemory singleton removal Sun Jan 4 10:10:02 2009 begin with 263462 relations and 487195 unique ideals Sun Jan 4 10:10:02 2009 reduce to 188876 relations and 123298 ideals in 8 passes Sun Jan 4 10:10:02 2009 max relations containing the same ideal: 40 Sun Jan 4 10:10:02 2009 removing 60921 relations and 43283 ideals in 17638 cliques Sun Jan 4 10:10:02 2009 commencing inmemory singleton removal Sun Jan 4 10:10:02 2009 begin with 127955 relations and 123298 unique ideals Sun Jan 4 10:10:02 2009 reduce to 123433 relations and 75094 ideals in 5 passes Sun Jan 4 10:10:02 2009 max relations containing the same ideal: 30 Sun Jan 4 10:10:02 2009 removing 41509 relations and 23871 ideals in 17638 cliques Sun Jan 4 10:10:03 2009 commencing inmemory singleton removal Sun Jan 4 10:10:03 2009 begin with 81924 relations and 75094 unique ideals Sun Jan 4 10:10:03 2009 reduce to 75965 relations and 44334 ideals in 6 passes Sun Jan 4 10:10:03 2009 max relations containing the same ideal: 20 Sun Jan 4 10:10:03 2009 relations with 0 large ideals: 6808 Sun Jan 4 10:10:03 2009 relations with 1 large ideals: 22842 Sun Jan 4 10:10:03 2009 relations with 2 large ideals: 27018 Sun Jan 4 10:10:03 2009 relations with 3 large ideals: 14236 Sun Jan 4 10:10:03 2009 relations with 4 large ideals: 3782 Sun Jan 4 10:10:03 2009 relations with 5 large ideals: 1228 Sun Jan 4 10:10:03 2009 relations with 6 large ideals: 51 Sun Jan 4 10:10:03 2009 relations with 7+ large ideals: 0 Sun Jan 4 10:10:03 2009 commencing 2way merge Sun Jan 4 10:10:03 2009 reduce to 54878 relation sets and 23247 unique ideals Sun Jan 4 10:10:03 2009 commencing full merge Sun Jan 4 10:10:04 2009 memory use: 1.8 MB Sun Jan 4 10:10:04 2009 found 31034 cycles, need 26323 Sun Jan 4 10:10:04 2009 weight of 26323 cycles is about 1136431 (43.17/cycle) Sun Jan 4 10:10:04 2009 distribution of cycle lengths: Sun Jan 4 10:10:04 2009 1 relations: 6808 Sun Jan 4 10:10:04 2009 2 relations: 3737 Sun Jan 4 10:10:04 2009 3 relations: 2697 Sun Jan 4 10:10:04 2009 4 relations: 2258 Sun Jan 4 10:10:04 2009 5 relations: 2017 Sun Jan 4 10:10:04 2009 6 relations: 1728 Sun Jan 4 10:10:04 2009 7 relations: 1469 Sun Jan 4 10:10:04 2009 8 relations: 1322 Sun Jan 4 10:10:04 2009 9 relations: 1226 Sun Jan 4 10:10:04 2009 10+ relations: 3061 Sun Jan 4 10:10:04 2009 heaviest cycle: 15 relations Sun Jan 4 10:10:04 2009 matrix not dense enough, retrying Code:
error: too many merge attempts I tried again, but the same error appeared. This factorization should be easy, so why did this happen? 
20090104, 11:46  #2 
Apr 2007
Spessart/Germany
2×3^{4} Posts 
Hello,
maybe it is a problem if the number to factor has still 3 factors (I don't know for sure). I got this factor with GMPECM: 2512367625515745823316347399 then I factored the remaining cofactor (61 digit) with msieve without any problem: Code:
Sun Jan 04 12:39:56 2009 Msieve v. 1.38 Sun Jan 04 12:39:56 2009 random seeds: 573941e0 13092148 Sun Jan 04 12:39:56 2009 factoring 6334400827126655789146320853263788162714153399858827568268317 (61 digits) Sun Jan 04 12:39:56 2009 searching for 15digit factors Sun Jan 04 12:39:57 2009 commencing quadratic sieve (61digit input) Sun Jan 04 12:39:57 2009 using multiplier of 17 Sun Jan 04 12:39:57 2009 using 32kb Intel Core sieve core Sun Jan 04 12:39:57 2009 sieve interval: 6 blocks of size 32768 Sun Jan 04 12:39:57 2009 processing polynomials in batches of 34 Sun Jan 04 12:39:57 2009 using a sieve bound of 68713 (3400 primes) Sun Jan 04 12:39:57 2009 using large prime bound of 3435650 (21 bits) Sun Jan 04 12:39:57 2009 using trial factoring cutoff of 22 bits Sun Jan 04 12:39:57 2009 polynomial 'A' values have 8 factors Sun Jan 04 12:40:04 2009 3726 relations (1666 full + 2060 combined from 17012 partial), need 3496 Sun Jan 04 12:40:04 2009 begin with 18678 relations Sun Jan 04 12:40:04 2009 reduce to 5488 relations in 2 passes Sun Jan 04 12:40:04 2009 attempting to read 5488 relations Sun Jan 04 12:40:04 2009 recovered 5488 relations Sun Jan 04 12:40:04 2009 recovered 4720 polynomials Sun Jan 04 12:40:04 2009 attempting to build 3726 cycles Sun Jan 04 12:40:04 2009 found 3726 cycles in 1 passes Sun Jan 04 12:40:04 2009 distribution of cycle lengths: Sun Jan 04 12:40:04 2009 length 1 : 1666 Sun Jan 04 12:40:04 2009 length 2 : 2060 Sun Jan 04 12:40:04 2009 largest cycle: 2 relations Sun Jan 04 12:40:04 2009 matrix is 3400 x 3726 (0.4 MB) with weight 101936 (27.36/col) Sun Jan 04 12:40:04 2009 sparse part has weight 101936 (27.36/col) Sun Jan 04 12:40:04 2009 filtering completed in 3 passes Sun Jan 04 12:40:04 2009 matrix is 3161 x 3225 (0.4 MB) with weight 85336 (26.46/col) Sun Jan 04 12:40:04 2009 sparse part has weight 85336 (26.46/col) Sun Jan 04 12:40:04 2009 commencing Lanczos iteration Sun Jan 04 12:40:04 2009 memory use: 0.5 MB Sun Jan 04 12:40:04 2009 lanczos halted after 52 iterations (dim = 3158) Sun Jan 04 12:40:04 2009 recovered 63 nontrivial dependencies Sun Jan 04 12:40:05 2009 prp28 factor: 5180781695771039411729570263 Sun Jan 04 12:40:05 2009 prp34 factor: 1222672793238381544642569359055659 Sun Jan 04 12:40:05 2009 elapsed time 00:00:09 Matthias 
20090104, 11:57  #3 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
2·29·167 Posts 
Code:
msieve n 15914343565113172548972231940698266883214596825515126958094847260581103904401068017057483 # => end of story in 30 minutes. # better yet echo 15914343565113172548972231940698266883214596825515126958094847260581103904401068017057483 ecm c 200 25e4 ... Run 88 out of 200: Using B1=250000, B2=128992510, polynomial Dickson(3), sigma=1173506587 Step 1 took 504ms Step 2 took 356ms ********** Factor found in step 2: 5180781695771039411729570263 Found probable prime factor of 28 digits: 5180781695771039411729570263 Composite cofactor 3071803542331017086552710737407158208177897555176711820880941 has 61 digits msieve n 3071803542331017086552710737407158208177897555176711820880941 ... Sun Jan 4 03:54:20 2009 lanczos halted after 49 iterations (dim = 3001) Sun Jan 4 03:54:20 2009 recovered 64 nontrivial dependencies Sun Jan 4 03:54:20 2009 prp28 factor: 2512367625515745823316347399 Sun Jan 4 03:54:20 2009 prp34 factor: 1222672793238381544642569359055659 Sun Jan 4 03:54:20 2009 elapsed time 00:00:10 Done in 5 minutes. 
20090104, 12:21  #4  
Nov 2008
2×3^{3}×43 Posts 
Quote:
You do know your computer's far faster than mine, don't you? Anyway, why did the filtering fail? Last fiddled with by 10metreh on 20090104 at 12:23 

20090104, 12:38  #5 
Just call me Henry
"David"
Sep 2007
Liverpool (GMT/BST)
2^{6}×3×31 Posts 

20090104, 12:51  #6 
Nov 2008
2×3^{3}×43 Posts 
I don't need to try again now I know it isn't a 2brilliant. I'm not trying to completely factor all the numbers near 2^293, I'm trying to find 2brilliants in the area. This means that I eliminate a number once I know it is not a 2brilliant.
Last fiddled with by 10metreh on 20090104 at 12:52 
20090104, 12:52  #7 
Just call me Henry
"David"
Sep 2007
Liverpool (GMT/BST)
2^{6}×3×31 Posts 

20090104, 12:54  #8 
Nov 2008
2×3^{3}×43 Posts 

20090104, 14:37  #9 
Tribal Bullet
Oct 2004
3·1,181 Posts 
It was so easy you had twice as many relations as you needed. Paradoxically, NFS postprocessing is much more difficult under those circumstances. Greg is running into the same problem in another thread, this time with an enormous number.

20090104, 15:12  #10  
Nov 2008
2×3^{3}×43 Posts 
Quote:
11e (if it existed) or even 10e might be better for this size number! Last fiddled with by 10metreh on 20090104 at 15:13 

20090104, 18:44  #11 
Nov 2008
912_{16} Posts 
Continuing my search, I reached 2^293531. I had about 90% finished ECMing it to 20 digits when I had a thought: Maybe I'll get a factor off the very last curve? I hadn't had this happen before, but sure enough:
Code:
GMPECM 6.1.3 [powered by GMP 4.2.2] [ECM] Input number is 2^293531 (89 digits) Run 77 out of 77: Using B1=11000, B2=1873422, polynomial x^1, sigma=383869318 Step 1 took 188ms Step 2 took 187ms ********** Factor found in step 2: 175238709850659009439 Found probable prime factor of 21 digits: 175238709850659009439 Probable prime cofactor (2^293531)/175238709850659009439 has 68 digits 
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