View Single Post
Old 2020-08-15, 02:15   #115
VBCurtis's Avatar
Feb 2005
Riverside, CA

3·1,579 Posts

Originally Posted by charybdis View Post
I doubt the poly scores predict sieving speed to the nearest 1%, but lambda 1.93 performs noticeably better than 1.88 and within a percent or so of 1.97. Suggests that the default 1.97 is close enough to optimal here that it's not worth trying to narrow it down further?

Next GNFS target in the HCN list is a c182. I'll keep most of the sieving params the same to get a direct comparison - experimentation can wait till the bunch of c184s if I decide to do them - but should lims go a bit higher? 105M/145M?
If I were to do another test, I'd try mfb0=59 with a tighter lambda setting; but you've shown 59 is slower than 58, and with 58 that not specifying lambda is as fast as 1.93. Your params are simpler, and likely faster than trying to find a fastest-lambda with 59.

As for changing lims: larger lims will improve relations per Q and may improve uniques per raw relations ratio, but at the expense of a slightly larger matrix. The rule of thumb I've been using is to target an ending Q somewhere near lim1; so, if your C180 runs have ending Q near 130M, I'd add 10M to both lims for C182. I don't have theory to back this, and keeping lim smallish while running Q well above lim1 may be faster overall.
The larger the job, the more Q will exceed lim1; my rule of thumb has helped me in the 140-175 digit range.
VBCurtis is offline   Reply With Quote