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
3·647 Posts 
Hello,
The message that jumps out at me is: Quote:
HTH Chris 

20191101, 20:13  #3 
"Curtis"
Feb 2005
Riverside, CA
41×109 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! 

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