[Halld-offline] zero field

[David Lawrence]

Hi Matt,

  The file is obtained via the JANA resource facility. Recall though that this relies on the
CCDB to provide the location (URL) of the file. It is then automatically downloaded and
installed. Subsequent invocations will see that the file is there and will just use it so
that it is not downloaded again.

  I can see now that I spoke too quickly before. Your file only has 53 z-locations in it instead
of the 701 it should. This probably means the field map file download was interrupted
and it is incomplete. You should delete the file “solenoid_1350_poisson_20130925”
and re-run. The file exists either in:

$JANA_RESOURCE_DIR/Magnets/Solenoid/solenoid_1350_poisson_20130925

or

/tmp/$USER/resources/Magnets/Solenoid/solenoid_1350_poisson_20130925

Note that there is a md5 checksum of the file stored in the CCDB along with the
URL. This is not currently checked every time you run a program, but it could be.
To check the sum of the existing file and what is in the CCDB, do the following:

harriet:JANA>ccdb dump Magnets/Solenoid/solenoid_1350_poisson_20130925
#
  https://halldweb1.jlab.org/resources   Magnets/Solenoid/solenoid_1350_poisson_20130925   3cb8da1e27b4f0cbce8fae765fcd59c9  
harriet:JANA>
harriet:JANA>
harriet:JANA>md5sum $JANA_RESOURCE_DIR/Magnets/Solenoid/solenoid_1350_poisson_20130925
3cb8da1e27b4f0cbce8fae765fcd59c9  /Users/davidl/HallD/resources/Magnets/Solenoid/solenoid_1350_poisson_20130925


Regards,
-David

On Jul 18, 2014, at 9:39 AM, Matthew Shepherd <mashephe at indiana.edu> wrote:

> 
> Using bfield2root I see something very odd (hope the attachment goes through).
> 
> The field only seems nonzero between z=-100 and z=-60
> 
> Matt
> <Screen Shot 2014-07-18 at 9.37.44 AM.png>
> 
> 
> 
> 
> 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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>> 
> 

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