Skip to content

ATLASMCP-98: uninitialised weight in MuonCalibrationAndSmearingTool

Sara Alderweireldt requested to merge salderwe/athena:ATLASMCP-98 into master

Relates to ATLASMCP-98.

We reported an issue where different results were observed repeating the SUSYTools ctests, originating from the MuonSmearingAndCalibrationTool. It appears variable m_IterWeight entered the r22 version of the code with !38708 (merged) but is never initialised. Multiplication with the uninitialised variable then causes random changes in the results.

I've copied the initialisation from the r21 version of the tool: https://gitlab.cern.ch/atlas/athena/-/blob/21.2/PhysicsAnalysis/MuonID/MuonIDAnalysis/MuonMomentumCorrections/Root/MuonCalibrationAndSmearingTool.cxx#L40

Tagging @jojungge so the Muon people can approve. If for some reason we don't want m_IterWeight, then it should instead be removed in L554, L564, and L572.

Also tagging @janders and @cmerlass for SUSYTools.

Merge request reports