Fix missing "False Alarm Probability" value in Coinc Table on GraceDB
Goal: make "False Alarm Probability" read the correct FAR value already provided in the coinc.xml
Problem
Currently we upload a coinc.xml file with a number of various LIGOLW tables, such as PostcohInspiralTable, SnglInspiralTable, CoincTable, and CoincInspiralTable, and so on. This data is then presented in GraceDb in a web dashboard - see this recently uploaded event for example: https://gracedb-playground.ligo.org/events/T765402/view/.
Note that the FAR value is provided in the "Basic Event Information" table, but it is not provided in the "Coinc Table".
For example, if we look at the screenshot below of spiir-O4-EW-development, we can see row.false_alarm_rate = row.fap
:
However, when viewing our output coinc.xml tables, false_alarm_rate is 0.
Expected Fix
To fix this, it's probably a simple fix to ensure that a value in the CoincTable for false alarm rate is properly set. I would first look somewhere in postcoh_finalsink.py. Secondly, we should verify if the "false alarm probability" should be "false alarm rate" - if it reads off the "false alarm rate" column in CoincInspiral then it's probably false alarm rate, rather than a probability.
It is possible that trigger.fap
is (incorrectly?) equal to 0, and we should instead be using trigger.far
. To fix this, first try replacing trigger.fap
with trigger.far
and running such that an event is uploaded to GraceDb. If the fix is successful (and FAR is the correct value to upload here), we should see a non-zero "False Alarm Probability" on GraceDb.