20191101, 04:21  #1 
Oct 2019
11 Posts 
CADONFS Square Root Error
I was trying to factor a c155, everything went well until:
Code:
Info:Linear Algebra: Starting Info:Linear Algebra: Total cpu/real time for bwc: 171995/12675.5 Info:Linear Algebra: Aggregate statistics: Info:Linear Algebra: Krylov: WCT time 7918.53, iteration CPU time 0.04, COMM 0.01, cpuwait 0.02, commwait 0.0 (114000 iterations) Info:Linear Algebra: Lingen CPU time 1287.91, WCT time 103.11 Info:Linear Algebra: Mksol: WCT time 4285.51, iteration CPU time 0.05, COMM 0.01, cpuwait 0.02, commwait 0.0 (57000 iterations) Info:Quadratic Characters: Starting Info:Quadratic Characters: Total cpu/real time for characters: 163.88/38.8057 Info:Square Root: Starting Info:Square Root: Creating file of (a,b) values Warning:Command: Process with PID 5600 finished with return code 11 Error:Square Root: Program run on server failed with exit code 11 Error:Square Root: Command line was: /root/Math/cadonfs/build/c3c/sqrt/sqrt poly ./snap/c155.poly prefix ./snap/c155.dep.gz purged ./snap/c155.purged.gz index ./snap/c155.index.gz ker ./snap/c155.kernel dep 0 t 8 side0 side1 gcd > ./snap/c155.sqrt.stdout.5 2> ./snap/c155.sqrt.stderr.5 Error:Square Root: Stderr output (last 10 lines only) follow (stored in file ./snap/c155.sqrt.stderr.5): Error:Square Root: Alg(3): start lifting mod p^39684643 (227310479 bits) at 2731.97s Error:Square Root: Alg(2): start lifting mod p^39705131 (227427833 bits) at 2733.72s Error:Square Root: Alg(4): start lifting mod p^39707377 (227440697 bits) at 2781.35s Error:Square Root: Alg(6): start lifting mod p^39707446 (227441093 bits) at 2814.16s Error:Square Root: Alg(5): start lifting mod p^39684923 (227312083 bits) at 2816.04s Error:Square Root: Alg(0): start lifting mod p^39699533 (227395768 bits) at 2837.66s Error:Square Root: Alg(7): maximal sqrt bitsize = 206709593 (91% of target size) Error:Square Root: Alg(7): square root lifted in 2357.35s Error:Square Root: fork: Cannot allocate memory Error:Square Root: Traceback (most recent call last): File "./cadonfs.py", line 122, in <module> factors = factorjob.run() File "./scripts/cadofactor/cadotask.py", line 5885, in run last_status, last_task = self.run_next_task() File "./scripts/cadofactor/cadotask.py", line 5977, in run_next_task return [task.run(), task.title] File "./scripts/cadofactor/cadotask.py", line 4871, in run raise Exception("Program failed") Exception: Program failed Last fiddled with by Ferrier on 20191101 at 04:21 
20191101, 16:43  #2  
Sep 2009
2^{2}·479 Posts 
Hello,
The message that jumps out at me is: Quote:
HTH Chris 

20191101, 20:13  #3 
"Curtis"
Feb 2005
Riverside, CA
2^{6}·3·23 Posts 
I also have had this error, and indeed the system was quite busy. I killed a few other tasks and freed up ~10GB of memory, and the sqrt finished without issue.
I'm not saying 10GB is needed; I don't recall what size task I was running, for one thing. But I'm pretty sure Chris is right and you were merely out of memory. 
20191101, 23:51  #4  
Oct 2019
11 Posts 
Quote:
This time I tried to resize the server to 16 threads with 32GB Memory, the highest hit was like about 12GB. And the result came out quickly with no error. Thanks! 

Thread Tools  
Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Square Root Days  davar55  Lounge  0  20160316 20:19 
NFS Square root problems  paul0  Factoring  10  20150119 12:25 
square root crash  bsquared  Msieve  17  20100409 14:11 
Square root of 3  Damian  Math  3  20100101 01:56 
Divisible up to Square Root  davar55  Puzzles  3  20070905 15:59 