MRTCAL indexes IMBFITS files in the so-called index files. A raw index file named index.mrt can be produced with the command INDEX BUILD (see command help for more advanced uses). When one or more index files are then reopened for reading, the command INDEX OPEN builds a memory index named the ``Input indeX'' (IX). At this stage, IX gathers the summary of all entries in all opened index files. From this full set, the command MFIND can be used to make a selection of desired entries: This is the ``Current indeX'' (CX).
While the primary purpose of the index files is to reference
IMBFITS files, their other advantage is to store other
products that can be derived from the IMBFITS files. In
particular, after the calibration, the commands CALIBRATE
and PIPELINE will save new versions of each
calibrated entry. These new versions have a modified calibration
status (from none to failed, empty, or
done), and optionally a calibration section added (storing the
calibration results). These modified versions of the entries are
themselves saved in an index file (either the original one, or a new
one, depending on the user choice), AND are implicitly appended to
IX. After the calibration process, it is then easy for the user to
select from IX the calibrated entries (or failed, or pending,
etc). The figure shows a basic example of these steps.
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