Migrate PixelDigitization to use IAtRNGSvc for AthenaMT

In order to make the output of MT MC Overlay (and digitization) reproducible then we need to use the thread-safe random number service (via IAtRNGSvc) in all digitization code. This merge request does this for the Pixel Digitization code. The approach taken is to retrieve the CLHEP::HepRandomEngine instance re-seeded for the current event in a method of the PileUpTool which is called once per event, this is then as an argument in calls to other methods where random numbers are required. This helps to make those tools (more) const.

Due to the slightly different way that the random number seeding is done in the MT service, the output is slightly different, but this should just be statistical.

added 1 commit

• fc6a307a - Migrate PixelDigitization to use IAtRNGSvc for AthenaMT

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Jenkins please retry a build

This merge request affects 1 package:

• InnerDetector/InDetDigitization/PixelDigitization

Adding @jchapman as watcher

CI Result FAILURE

	Athena	AthSimulation
externals
cmake
make
required tests
optional tests

Full details available at NICOS MR-20297-2019-01-14-18-25
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST 32210] (for remote access see the FAQ for MR reviewers)

Everything ran fine. Overlay output changes slightly as expected. (Digitization output would also change slightly, but this is not checked by the CI tests.)

changed the description

Hi @stsuno,

Before I drop the WIP status on this merge request, I wanted to check that these changes are OK with you. Could you take a look when you have a minute please? Hopefully these changes don't conflict with any other changes that you're working on at the moment.

Cheers,

John

Hello, John, I think it's fine. Cheers, Soshi

unmarked as a Work In Progress

added review-pending-level-1 label

Thanks for taking a look @stsuno!

From the last discussion comments, look like this MR is fine. Approving.

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

merged

mentioned in commit c98d2ddb

added sweep:ignore label

@amete, I think we need an overlay reference update again

Thanks!

@tadej Done

Thanks @amete, we really need to come-up with something smarter to reduce the load on you :)

I'm gonna put a MR on that soon

mentioned in merge request !20516 (merged)

mentioned in commit 6790f3c8