Fill all of covariance matrix in refitted track parameters

AmgSymMatrix, despite the name, does not actually fill symmetrically: you have to go through and fill (i, j) and (j, i) separately. Someone (almost certainly me) overlooked this, probably during CLHEP->Eigen migration.

As a postscript, I did supervise a project a few years ago to get Eigen matrices filled symmetrically and stored in half-diagonal form, but it did not fully converge: https://indico.cern.ch/event/738804/contributions/3106176/attachments/1700771/2738969/GSoC2018_ACTS_Developer_Meeting.pdf

Should say that I did not see any difference in tracking output (expert-monitoring.root) or chain counts, with 100 events full menu test.

I think there is also the fillSymmetric in the plugins, but basically will end up doing something very similar ....

https://acode-browser1.usatlas.bnl.gov/lxr/search?%21v=head&_filestring=&_string=fillSymmetric

This merge request affects 1 package:

• Trigger/TrigTools/TrigInDetTrackFitter

This merge request affects 1 file:

• Trigger/TrigTools/TrigInDetTrackFitter/src/TrigInDetTrackFitter.cxx

Adding @sutt ,@nagano ,@keli as watchers

added Trigger TriggerID main review-pending-level-1 labels

The system determined that CI tests (with names matching "^CITest_SimulationRun(2|3)(FullSim|Hit).*$") are not needed for this code change. They are not run. This is not an indicator to restart the job.

CI Result SUCCESS (hash fa53669b)

	Athena
externals
cmake
make
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For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 77285]

Changes look fine from L1 perspective - Approving.

Cheers, Steffen (L1)

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit a99f6297