reglom is a utility that has at least two use cases:
If you have an event built run with data late conditions, reglom can rebuild the event file with properly ordered data. This can happen with, e.g. DDAS if the FIFO_THRESHOLD values are not set properly to allow for differing rates in different readout systems.
If you find that you want to rebuild event built data using a different coincidence window, reglom can do that as well.
reglom is actually a script that accepts event building parameters, a run to reglom and an output file. Reglomming occurs in two stages:
The input run is unglommed into event files consisting of data
from each of the source ids. These files are temporary
and have names like sid-sid
where sid is the input source id of
the data in that file. These files are written in the
current working directory. You must therefore have
write access to this directory and sufficient quota
to allow these files to be written.
The files generated by the unglom stage are then fed as ordered fragments into the NSCLDAQ glom command which produces, as output, the rebuilt event file.
Note that while NSCLDAQ must be installed on the system running reglom, it need to be running (that is the servers that manage ringbuffers don't have to be running as no ring buffers are created or used).
reglom provides a GUI to steer the reglomming process. The top part of the GUI accepts parameters used by glom, specifically the coincidence interval used to build fragments into events, the output sourceid and the policy used to provide timestamps to the output events.
The middle part of the GUI allows you to select the run to reglom. If your run is a multi-segmented run, choose any segment file in the run. All files will be reglommed into a single output event file that combines all the event fragments in all segments. The values accepted here are saved in the file ~/.reglom. If that file is present, default values are loaded from that file, allowing you to perform several reglom operations using the same settings.
The bottom part of the GUI allows you to select the output event file name. This is the file created by reglom that will contain the rebuilt data.
To proceed with the reglom, click the button. To do nothing, click .
As the unglom phase runs, the script shows the size of each of the segment files and any messages emitted by the unglom program. Similarly, as the glom phase runs, the script shows how the size of the output file grows and any messages from the reglom/glom pipeline