[Halld-offline] zero field

[Matthew Shepherd]

Great -- thanks.

It was going to catch someone at some point.  (I'm
assuming I'm not the only one that hits ctrl-c when I realize
that I've just executed a long program with 
incorrect arguments.)  The field download takes
a while and happens right at the time you realize you
made an execution mistake.

For such a large system with so many users and
possible permutations of use it is really important
to make every sanity check possible and abort
immediately when something doesn't seem right.

Matt

---------------------------------------------------------------------
Matthew Shepherd, Associate Professor
Department of Physics, Indiana University, Swain West 265
727 East Third Street, Bloomington, IN 47405

Office Phone:  +1 812 856 5808

On Jul 18, 2014, at 10:23 AM, David Lawrence <davidl at jlab.org> wrote:

> 
> Hi Matt,
> 
>  Sorry this has cost you so much time. You’re the first person to
> report this as an issue in the 6 months since it was deployed. I’ll
> go ahead and put in the code to generate and check the md5
> checksum whenever a program is started so that an error can
> be flagged if there is a mismatch.
> 
> Regards,
> -David
> 
> On Jul 18, 2014, at 10:15 AM, Matthew Shepherd <mashephe at indiana.edu> wrote:
> 
>> 
>> With bits and pieces from 3 different people,  I think 
>> I've figured this out...  gggrrrrrr!
>> 
>> Mike Staib suggested my log seemed to indicate my field doesn't have
>> enough z points.
>> 
>> It seems like jana is using JANA_RESOURCE_DIR to cache fields.  (I got
>> this from Paul.. I've never set this, but grep and reading jana source 
>> tells me it is set by default to /tmp/username/resources.)
>> 
>> If I go to that directory and delete it and rerun bfiled2root, I get 
>> a full field.
>> 
>> What happened?  Here's my theory:
>> 
>> I ran a job and that job chose to download the field.  This
>> is the first time consuming thing that happens in a job.  If, 
>> during the field download you kill the job with ctrl-c then 
>> you are left with a partial field.
>> (I tested this out and was able to repeat it.)
>> 
>> I must have been unlucky and hit ctrl-c on the job that
>> tried to download the field.  Note this is normal for must users.
>> It is easy to execute a command accidentally or realize just
>> after you press return that you didn't specify all the arguments
>> that you wanted.
>> 
>> This is a really nasty behavior because every subsequent job
>> then just reads this partial field and never prints any message
>> or error.
>> 
>> Can we put some sort of check in the field?  Write the number
>> of points in the file first.  And then on read back when there
>> isn't than many points abort with an error.
>> 
>> nasty nasty nasty... that cost Paul and me a ton of time
>> this week
>> 
>> Matt
>> 
>> ---------------------------------------------------------------------
>> Matthew Shepherd, Associate Professor
>> Department of Physics, Indiana University, Swain West 265
>> 727 East Third Street, Bloomington, IN 47405
>> 
>> Office Phone:  +1 812 856 5808
>> 
>> On Jul 18, 2014, at 7:18 AM, David Lawrence <davidl at jlab.org> wrote:
>> 
>>> 
>>> Hi Matt,
>>> 
>>> The output looks right. What happens if you run the bfield2root utility? This should
>>> be built as part of the default sim-recon build. (Source is in $HALLD_HOME/src/programs/Utilities/bfield2root)
>>> 
>>> Draw the field map in ROOT using:
>>> 
>>>> bfield2root
>>>> root bfield.root
>>> root [1] Bz_vs_r_vs_z->Draw("colz")
>>> 
>>> Also, how are you checking that the field map is returning zeros?
>>> 
>>> Regards,
>>> -David
>>> 
>>> On Jul 17, 2014, at 9:49 PM, Matthew Shepherd <mashephe at indiana.edu> wrote:
>>> 
>>>> 
>>>> Hi all,
>>>> 
>>>> Paul and I have been trying to understand why I cannot
>>>> get the example analysis software working and we seem
>>>> to have traced the problem down to the fact that the 
>>>> magnetic field map is returning a zero field.
>>>> 
>>>> Does anyone know how to debug this?  The startup
>>>> of the job suggests all is OK (I think):
>>>> 
>>>> JANA >>URL: sqlite:////home/s4/mashephe/gluex/ccdb.sqlite
>>>> JANA >>context: default
>>>> JANA >>Reading Magnetic field map from Magnets/Solenoid/solenoid_1350_poisson_20
>>>> 130925 ...
>>>> Nx=251 Ny=1 Nz=43 )  at 0x7f46720a0ce0
>>>> Fine-mesh evio file does not exist.
>>>> Constructing the fine-mesh B-field map...
>>>> rmin: 0 rmax: 88.5 dr: 0.1 zmin: 0 zmax: 600 dz: 0.1vg.: 0.0Hz)     
>>>> Number of points in z = 6000
>>>> Number of points in r = 885
>>>> JANA >>10599 entries found (Created Magnetic field map of type DMagneticFieldMap
>>>> 
>>>> I'm using:
>>>> 
>>>> sim-recon-2014-06-30
>>>> ccdb_1.02
>>>> hdds-2.1
>>>> jana_0.7.1p3
>>>> 
>>>> and a ccdb.sqlite file from July 14 (copied from Mark's web page link that day).  I've also
>>>> tried the ccdb.sqlite file from dc2 conditions.
>>>> 
>>>> Matt
>>>> 
>>>> 
>>>> ---------------------------------------------------------------------
>>>> Matthew Shepherd, Associate Professor
>>>> Department of Physics, Indiana University, Swain West 265
>>>> 727 East Third Street, Bloomington, IN 47405
>>>> 
>>>> Office Phone:  +1 812 856 5808
>>>> 
>>>> 
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>>> 
>> 
>