Description of the Correlator Output Format
j2ms2 expects the following directory setup.
- Every experiment has its own directory, the experiment root-directory,
<exp-root>
- Data for this experiment is correlated on a job/subjob-basis. Each job has
its own subdirectory under the <exp-root> directory. This directory is the
<job-root>
- Subjobs contain the actual data produced. Every subjob has a
'parent' job and has its own directory under the <job-root>
directory. This directory, surprisingly, is known as the <subjob-root>
For the <job-root> and <subjob-root> names the following holds:
the are the RELATIVE names of the directory, so e.g. the <subjob-root>
is the name of the subjob.
In order for j2ms2 to work correctly, the following files must be
present (the contents will be discussed here):
- In the <exp-root> there needs to be a file (or sym-link!)
called <exp-root-base>.vix
(the experiment VEXfile) where <exp-root-base> is the
'basename' of the <exp-root> directory, i.e. the last
part of the full path.
- When a subjob is to be translated, j2ms2 looks in
<exp-root>/<job-root>/<subjob-root> for
COF-datafiles (like CDF,MAP).
- In the directory <exp-root>/<job-root>, j2ms2 expects
a file called <exp-code>_<job-root>.vex
(the job VEXfile), where <exp-code> is the experiment
code as found in the .vix file in
the <exp-root> directory.
Graphically:
| ...../<exp-root>/ |
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/exp-vix |
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/<job-root-1>/ |
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/job-vex |
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/<subjob-root-1>/ |
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/CDF |
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/MAP |
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/TPSTATn |
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/.... |
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/<subjob-root-n>/ |
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/<job-root-n>/ |
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CONTENTS OF THE FILES
- <exp-root>/<exp-root-base>.vix:
- This is the top-level VEX-file. The experiment's code is read
from the $EXPER block in this file. Also, the source,
frequency and antenna databases are initialised from this
VEX-file. The order of the sources and antennas in this file
determines their ID in the resulting MeasurementSet(s).
- <exp-root>/<job-root>/<exp-code>_<job-root>.vix:
- This is the job-specific VEX file. It tells j2ms2 how the
experiment was correlated. It looks for an entry like this in
the VEX file (note that it is a *comment*!):
* prep_job .....
A line matching this is parsed and j2ms2 searches the line for:
where the -c option indicates the correlator configuration and
the -i indicates the integration time. For the -i option j2ms2
accepts floating point notation.
Furthermore, j2ms2 uses this file for time -> scan
mapping. When data is read back, the time is decoded and the
system will look in this file to see if and if so, which scan
the data came from. Note that only data for which a scan is
found is written into the resulting MeasurementSet. Via this
file you could influence if individual scan(s) should be
written to the MS (if you wanted to).
Marjolein Verkouter
Last modified: Mon Nov 29 18:11:21 MET 1999