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Old 2015-02-25, 17:29   #1
Dubslow
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Default Oops (need help recovering factorization)

So I resumed a matrix with -nc2 (forgetting about -ncr, and losing about ~30 minutes of work because of that), then went to bed while the matrix was solving. Unfortunately for me, I was running this from a sh script, and immediately after finishing the -nc2, Yafu didn't -nc3 like I was erroneously expecting, and the sh script launched the next factorization automatically.

Is it possible for me to recover the nearly finished factorization? The next job overwrote nfs.dat, but not much else; I recovered the poly just fine, and the following files were seemingly left intact, which I believe includes everything I need (i.e. the dependencies), but not the relations. Is there any way I can get the relations back, even just most of them? All told I spent a couple of days sieving this, so even 1 hour of sieving + redoing the 3 hr matrix would be a help.

Code:
-rw-r--r--  1 bill bill  93655656 Feb 24 22:56 nfs.dat.bak.chk
-rw-r--r--  1 bill bill         0 Feb 24 18:11 nfs.dat.br
-rw-r--r--  1 bill bill  93655656 Feb 25 00:10 nfs.dat.chk
-rw-r--r--  1 bill bill  60978516 Feb 24 18:14 nfs.dat.cyc
-rw-r--r--  1 bill bill  18730360 Feb 25 01:22 nfs.dat.dep
-rw-r--r--  1 bill bill     12288 Feb 24 18:12 nfs.dat.hc
-rw-r--r--  1 bill bill 675824564 Feb 24 18:14 nfs.dat.mat
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Old 2015-02-25, 17:55   #2
Batalov
 
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Quote:
Originally Posted by Dubslow View Post
Is it possible for me to recover the nearly finished factorization? The next job overwrote nfs.dat
No, it is now done for. You will not be able to do the sqrt -- the matrix does not contain relations; they are in .dat and referenced via .cyc.

(You can actually do the LA again, but that will be the end of the road. This is a common trick for large factorizations - only .mat, .cyc, .chk, .fb and .ini files are needed and LA can be run and then .dep is transferred back to the original "mother" computer where .dat must be present.)
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Old 2015-02-25, 18:34   #3
Dubslow
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Damn, I was hoping one of those was a backup data file or something. Oh well...
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Old 2015-02-25, 19:02   #4
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Quote:
Originally Posted by Dubslow View Post
So I resumed a matrix with -nc2 (forgetting about -ncr, and losing about ~30 minutes of work because of that), then went to bed while the matrix was solving. Unfortunately for me, I was running this from a sh script, and immediately after finishing the -nc2, Yafu didn't -nc3 like I was erroneously expecting, and the sh script launched the next factorization automatically.
-nc3 was added in version 1.29, what version are you using? Note that it is just -nc3, not -nc3 with arguments... if you are trying to supply arguments to -nc3 then its possible yafu wouldn't like that.
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Old 2015-02-25, 19:06   #5
Dubslow
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Quote:
Originally Posted by bsquared View Post
-nc3 was added in version 1.29, what version are you using? Note that it is just -nc3, not -nc3 with arguments... if you are trying to supply arguments to -nc3 then its possible yafu wouldn't like that.
Poorly written on my part. What I meant is that it didn't run the square root stage, as I was expecting. I needed to run -nc2 -nc3 (or -ncr would have done square root too, I recall...?), but I only ran -nc2.
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Old 2015-02-25, 20:04   #6
xilman
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Quote:
Originally Posted by Dubslow View Post
Is there any way I can get the relations back, even just most of them? All told I spent a couple of days sieving this, so even 1 hour of sieving + redoing the 3 hr matrix would be a help.
Far too late for you now, but I learned (needless to say, the hard way) to script a move of all the remaining files from one factorization into a temporary directory before starting the next factorization. Recovered quite a few computations that way.

Then you have to learn to muck out multiple gigabytes of now useless files before they become embarassing. Fortunately, disks are now big enough that free space ran out.

One of the characteristics of intelligence is the ability to recognize a mistake the second time you make it.

Last fiddled with by xilman on 2015-02-25 at 20:04
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Old 2015-02-26, 01:32   #7
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Another rule of thumb strategy is to run every factorization (except trivial, deliberately throw-away) in a separate folder.
But the clean-up discipline is needed just the same as for the above recipe.
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