Actually these polynomials don't look too bad when I do trivial test sieving

[code]
> cat gnfs.1221
n: 13546883948707557394740613723103946152064130242660227238148207099694217967258945948090755858238134930723530286428679498807036076305750824074596099018755707927936366610675572615755463725831948023
Y0: -14769649678254236071870801775658732945
Y1: 4212581526470259037
c0: 260758480321916667685688193169037338514796556784
c1: 28369420161080102434132404082540766030308
c2: -319515688007256176977918750453824
c3: -976782223305603155968711
c4: 8240833399911082
c5: 19274736
skew: 191733447.30
lpbr: 33
lpba: 33
mfbr: 66
mfba: 66
alambda: 2.6
rlambda: 2.6
alim: 300000000
rlim: 300000000

> ./gnfs-lasieve4I16e gnfs.1221 -a -f 300000000 -c 3000
total yield: 11269, q=300003001 (0.55676 sec/rel)
[/code]

3.7 relations-per-Q, so probably could put alim=240M, sieve 20M-240M and get a decent matrix in about twelve Ivy-bridge-thread-years.

The 1.159e-14 polynomial got
[code]
total yield: 10352, q=300003001 (0.58905 sec/rel)
[/code]

so using the 1.221e-14 instead might reduce the sieving time by about six thread-months; we've spent three real-time-months searching to get these polynomials, which makes me think it's about time to stop polynomial selection and start some sieving.

Since yield is pretty good, might this be a candidate for 15e/33LP on NFS@home? I don't know of a GNFS194 attempted on 15e before.

How big is the matrix for the GNFS192.3 on 15e/32? That's postprocessing now, right?

It could be done with 15e;

[code]
> ./gnfs-lasieve4I15e gnfs.1221 -a -f 300000000 -c 3000
total yield: 4917, q=300003001 (0.62273 sec/rel)
> ./gnfs-lasieve4I15e gnfs.1221 -a -f 600000000 -c 3000
total yield: 4595, q=600003043 (0.76412 sec/rel)
[/code]

so 1.6 relations per Q, and 10% slower than using 16e. This is a big job, you might well need a billion relations, so Q=20M..600M. I'd expect it to be possible to over-sieve enough for the matrix to fit on a 32GB machine. It will take a month or so of real-time on nfs@home.

[QUOTE=VBCurtis;407179]How big is the matrix for the GNFS192.3 on 15e/32? That's postprocessing now, right?[/QUOTE]

[code]
Fri Jul 17 12:26:49 2015 matrix is 31471012 x 31471237 (14625.0 MB) with weight 3892604835 (123.69/col)
Fri Jul 17 12:26:49 2015 sparse part has weight 3519133867 (111.82/col)
Fri Jul 17 12:26:49 2015 using block size 8192 and superblock size 1179648 for processor cache size 12288 kB
Fri Jul 17 12:30:00 2015 commencing Lanczos iteration (6 threads)
Fri Jul 17 12:30:00 2015 memory use: 12537.6 MB
Fri Jul 17 12:32:06 2015 linear algebra at 0.0%, ETA 692h24m

3229 pumpkin 20 0 17.6g 17g 1372 R 540 54.9 79241:10 msieve
[/code]

(so it doesn't quite fit in a 16G machine)


For 3270.698, I ran a trial post-processing on Monday and got

450723464 relations; 334109142 unique; 287274746 unique ideals
Mon Aug 3 22:20:02 2015 weight of 26771795 cycles is about 3213101586 (120.02/cycle)

so I've added 50MQ more sieving to see what changes.

Thank you for the data! Very interesting, and shows the boundary for 16GB machines as GNFS ~190. I'll be very interested to see if 15e/33LP create a substantially larger matrix for the new job.

I have a 64G machine that could be used if the matrix gets really big (hopefully only the intermediate processing steps get really big and the matrix fits in 32G). Shall I stick this one onto the NFS@home queue and wait until autumn?

This might be the best way to handle it. The interest may not last to finish the sieving if requested by forum members.

Since the last step was a decrease, it may become more interesting if the sequence can keep dropping in size.

621M relations (484M unique, 519M unique ideals) are not enough to build a matrix for this C194. nfs@home sieving continues.

Should be getting close based on this [URL="http://www.mersenneforum.org/showpost.php?p=411821&postcount=377"]status[/URL].

Of course many things could postpone the results.

The computer crashed and it took a day or so before I had the spare time to bring it in from the outbuilding, clear out the fans, remove the broken GTX580 and put it back. Current ETA is tomorrow evening.

There may be a problem:

[code]
Sun Nov 1 13:23:24 2015 using block size 8192 and superblock size 1179648 for processor cache size 12288 kB
Sun Nov 1 13:26:41 2015 commencing Lanczos iteration (6 threads)
Sun Nov 1 13:26:41 2015 memory use: 12743.4 MB
Sun Nov 1 13:26:45 2015 restarting at iteration 418288 (dim = 26450011)
Sun Nov 1 13:28:48 2015 linear algebra at 76.8%, ETA 179h57m
Sun Nov 1 13:29:29 2015 checkpointing every 50000 dimensions
Wed Nov 4 17:25:52 2015 lanczos error: submatrix is not invertible
Wed Nov 4 17:25:52 2015 lanczos halted after 476936 iterations (dim = 30158654)
Wed Nov 4 17:25:52 2015 linear algebra failed; retrying...
Wed Nov 4 17:25:52 2015 commencing Lanczos iteration (6 threads)
Wed Nov 4 17:25:52 2015 memory use: 12743.4 MB
Wed Nov 4 17:25:53 2015 restarting at iteration 476799 (dim = 30150056)
Wed Nov 4 17:27:44 2015 linear algebra at 87.6%, ETA 87h 3m
Wed Nov 4 17:28:17 2015 error: corrupt state, please restart from checkpoint
...
Wed Nov 4 22:39:16 2015 restarting at iteration 476008 (dim = 30100040)
Wed Nov 4 22:41:18 2015 linear algebra at 87.5%, ETA 96h48m
Wed Nov 4 22:41:59 2015 checkpointing every 50000 dimensions
Sun Nov 8 15:13:43 2015 lanczos halted after 544333 iterations (dim = 34420477)
Sun Nov 8 15:14:23 2015 recovered 28 nontrivial dependencies
Sun Nov 8 15:14:25 2015 BLanczosTime: 319182
...
Sun Nov 8 16:18:55 2015 commencing square root phase
Sun Nov 8 16:18:55 2015 reading relations for dependency 1
Sun Nov 8 16:19:00 2015 read 17209116 cycles
Sun Nov 8 16:19:40 2015 cycles contain 57590394 unique relations
Sun Nov 8 16:31:14 2015 read 57590394 relations
Sun Nov 8 16:37:34 2015 multiplying 57590394 relations
Sun Nov 8 19:42:12 2015 multiply complete, coefficients have about 3750.18 million bits
Sun Nov 8 19:42:19 2015 error: relation product is incorrect
Sun Nov 8 19:42:19 2015 algebraic square root failed
[/code]

I will let it run overnight and see if all the relation products are incorrect, but this could mean I have to repeat the month-long linear algebra (at which point I would be quite inclined to ask if there's anyone here with cluster resource that could be used)