[Cado-nfs-discuss] Correct method for SNFS

snae at unseen.is snae at unseen.is
Mon Feb 19 11:41:27 CET 2018


Hello, 

I am understanding the CADO limits with 8GB of RAM: 
GNFS 
c150 cannot complete merge step 
c140 cannot complete linear step 

I am now trying to figure for SNFS 
Started with a simple poly 
# 2319970833914268555880710667073 ^ 7 - 1 
# MurphyE Score: 4.344e-11 anorm: 2.832e45 rnorm: 3.892e37. (Since anorm is larger, sieve with the "-a" parameter.) 
# SNFS difficulty is 182.193 which is approximately equivalent to GNFS difficulty 132. (Since n has 164 digits, it's recommended to use SNFS.) 
# (some extra msieve library info) size: 4.102e-09 alpha: 2.428 rroots: 0 
n: 13575277223327551269731511292438842668608227521769505116539991525658348687295357093606009150069381658286687218200783219113236101625115054803147464380663663350482801 
skew: 1.31650 
type: snfs 
c6: 1 
c5: 1 
c4: 1 
c3: 1 
c2: 1 
c1: 1 
c0: 1 
Y1: 1 
Y0: -2319970833914268555880710667073 
m: 2319970833914268555880710667073 
rlambda: 2.5 
alambda: 2.5 
lpbr: 28 
lpba: 28 
mfbr: 56 
mfba: 56 
alim: 10000000 
rlim: 10000000 
qintsize: 80000 


Then build the parameter file: 
name = B7 
N = 13575277223327551269731511292438842668608227521769505116539991525658348687295357093606009150069381658286687218200783219113236101625115054803147464380663663350482801 

lim0 = 10000000 
lim1 = 10000000 
lpb0 = 28 
lpb1 = 28 


tasks.polyselect.admin = 0 
tasks.polyselect.admax = 0 
tasks.polyselect.adrange = 0 

tasks.polyselect.import = /home/<computer>/Math/64bit_new/b7.poly 

tasks.sieve.mfb0 = 56 
tasks.sieve.mfb1 = 56 
tasks.sieve.lambda0 = 2.5 
tasks.sieve.lambda1 = 2.5 
tasks.I = 12 
tasks.sieve.qmin = 2000000 
tasks.sieve.qrange = 80000 
tasks.sieve.sqside = 0 

# linear algebra 
tasks.linalg.m = 64 
tasks.linalg.n = 64 
tasks.linalg.characters.nchar = 50 


With the b7.poly 
# 2319970833914268555880710667073 ^ 7 - 1 
# MurphyE Score: 4.344e-11 anorm: 2.832e45 rnorm: 3.892e37. (Since anorm is larger, sieve with the "-a" parameter.) 
# SNFS difficulty is 182.193 which is approximately equivalent to GNFS difficulty 132. (Since n has 164 digits, it's recommended to use SNFS.) 
# (some extra msieve library info) size: 4.102e-09 alpha: 2.428 rroots: 0 
n: 13575277223327551269731511292438842668608227521769505116539991525658348687295357093606009150069381658286687218200783219113236101625115054803147464380663663350482801 
skew: 1.31650 
type: snfs 
c6: 1 
c5: 1 
c4: 1 
c3: 1 
c2: 1 
c1: 1 
c0: 1 
Y1: 1 
Y0: -2319970833914268555880710667073 
#m: 2319970833914268555880710667073 
#rlambda: 2.5 
#alambda: 2.5 
#lpbr: 28 
#lpba: 28 
#mfbr: 56 
#mfba: 56 
#alim: 10000000 
#rlim: 10000000 
#qintsize: 80000 

When I try to run it appears promising but then just stops at the Lattice Sieving: 

~/Desktop/cado-nfs$ ./cado-nfs.py ~/Math/64bit_new/parameters.B7 
Info:root: No database exists yet 
Info:root: Created temporary directory /tmp/cado.pkgzbecl 
Info:Database: Opened connection to database /tmp/cado.pkgzbecl/B7.db 
Info:root: Set tasks.threads=8 based on detected logical cpus 
Info:root: tasks.polyselect.threads = 2 
Info:root: tasks.sieve.las.threads = 2 
Info:root: Command line parameters: ./cado-nfs.py /home/<computer>/Math/64bit_new/parameters.B7 
Info:root: If this computation gets interrupted, it can be resumed with ./cado-nfs.py /tmp/cado.pkgzbecl/B7.parameters_snapshot.0 
Info:HTTP server: Using non-threaded HTTPS server 
Info:Complete Factorization: Factoring 13575277223327551269731511292438842668608227521769505116539991525658348687295357093606009150069381658286687218200783219113236101625115054803147464380663663350482801 
Info:HTTP server: serving at https://<computer>:34887 (0.0.0.0) 
Info:HTTP server: For debugging purposes, the URL above can be accessed if the server.only_registered=False parameter is added 
Info:HTTP server: You can start additional cado-nfs-client.py scripts with parameters: --server=https://<computer>:34887 --certsha1=bf01c2becfa2974b39592a187a4e221f7d50a7db 
Info:HTTP server: If you want to start additional clients, remember to add their hosts to server.whitelist 
Info:Polynomial Selection (size optimized): Skipping this phase, as we will import the final polynomial 
Info:Polynomial Selection (root optimized): Starting 
Info:Polynomial Selection (root optimized): Importing file /home/<computer>/Math/64bit_new/b7.poly 
Warning:Polynomial Selection (root optimized): Polynomial in file /home/<computer>/Math/64bit_new/b7.poly has no Murphy E value 
Info:Polynomial Selection (root optimized): New best polynomial from file /home/<computer>/Math/64bit_new/b7.poly: Murphy E = 0 
Info:Polynomial Selection (root optimized): Best polynomial previously found in /home/<computer>/Math/64bit_new/b7.poly has Murphy_E = 0 
Info:Polynomial Selection (root optimized): Imported polynomial, skipping this phase 
Info:Generate Factor Base: Starting 
Info:Generate Factor Base: Finished 
Info:Generate Factor Base: Total cpu/real time for makefb: 13.15/2.13618 
Info:Generate Free Relations: Starting 
Info:Generate Free Relations: Found 2438537 free relations 
Info:Generate Free Relations: Finished 
Info:Generate Free Relations: Total cpu/real time for freerel: 317.12/41.0906 
Info:Lattice Sieving: Starting 
Info:Lattice Sieving: We want 22129742 relation(s) 
Info:Lattice Sieving: Adding workunit B7_sieving_2000000-2080000 to database 
Info:Lattice Sieving: Adding workunit B7_sieving_2080000-2160000 to database 
Info:Lattice Sieving: Adding workunit B7_sieving_2160000-2240000 to database 
Info:Lattice Sieving: Adding workunit B7_sieving_2240000-2320000 to database 
Info:Lattice Sieving: Adding workunit B7_sieving_2320000-2400000 to database 
Info:Lattice Sieving: Adding workunit B7_sieving_2400000-2480000 to database 
Info:Lattice Sieving: Adding workunit B7_sieving_2480000-2560000 to database 
Info:Lattice Sieving: Adding workunit B7_sieving_2560000-2640000 to database 
Info:Lattice Sieving: Adding workunit B7_sieving_2640000-2720000 to database 
Info:Lattice Sieving: Adding workunit B7_sieving_2720000-2800000 to database 


Note it states it is doing lattice sieving but there are no processes running. 
What is the correct method for approaching a SNFS? 
What needs to updated in the parameter or poly files? 
Is there a method for using just one file? 




# 2319970833914268555880710667073 ^ 7 - 1 
# MurphyE Score: 4.344e-11 anorm: 2.832e45 rnorm: 3.892e37. (Since anorm is larger, sieve with the "-a" parameter.) 
# SNFS difficulty is 182.193 which is approximately equivalent to GNFS difficulty 132. (Since n has 164 digits, it's recommended to use SNFS.) 
# (some extra msieve library info) size: 4.102e-09 alpha: 2.428 rroots: 0 
n: 13575277223327551269731511292438842668608227521769505116539991525658348687295357093606009150069381658286687218200783219113236101625115054803147464380663663350482801 
skew: 1.31650 
type: snfs 
c6: 1 
c5: 1 
c4: 1 
c3: 1 
c2: 1 
c1: 1 
c0: 1 
Y1: 1 
Y0: -2319970833914268555880710667073 
#m: 2319970833914268555880710667073 
#rlambda: 2.5 
#alambda: 2.5 
#lpbr: 28 
#lpba: 28 
#mfbr: 56 
#mfba: 56 
#alim: 10000000 
#rlim: 10000000 
#qintsize: 80000 
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