Transformer to create tracks from gen particles

[BrieucF]

BEGINRELEASENOTES

• Add a transformer to create Tracks out of generated particles
• Add a consumer that plots the distance between simTrackerHits and a Track
  ENDRELEASENOTES

[jmcarcell]

Some comments. I didn't run it, but it looks fine

[jmcarcell]

Here I'd say it's preferrable to print a message if the file is not there, but always running forcefully ddsim is maybe a bit too much. Note that this will run as soon as the file is processed, before anything related to Gaudi has been loaded or checked.

[BrieucF]

Hi Juan, thanks for the comments! Not sure I understand this one though. This line is just for convenience (and for tests). So that I can run/test the genTracking just calling one script

[jmcarcell]

A couple more comments:

• In the steering file it would be good to get rid of PodioInput and PodioOutput and use IOSvc like in https://github.com/key4hep/k4FWCore/blob/971ae2da7efec5a167b4ab6ecf365c0e27ca41ca/test/k4FWCoreTest/options/ExampleFunctionalFile.py#L28. It should work with PodioInput and PodioOutput but if you ever want to run multithreaded it won't
• For histogramming I think that works fine, but since a few days ago there is an example in k4FWCore: https://github.com/key4hep/k4FWCore/blob/971ae2da7efec5a167b4ab6ecf365c0e27ca41ca/test/k4FWCoreTest/src/components/ExampleFunctionalTransformerHist.cpp and https://github.com/key4hep/k4FWCore/blob/971ae2da7efec5a167b4ab6ecf365c0e27ca41ca/test/k4FWCoreTest/options/ExampleFunctionalTransformerHist.py where in the cpp file you only need to fill the histogram and the exporting gets done by the RootHistSvc.

[BrieucF]

For histogramming I think that works fine, but since a few days ago there is an example in k4FWCore: https://github.com/key4hep/k4FWCore/blob/971ae2da7efec5a167b4ab6ecf365c0e27ca41ca/test/k4FWCoreTest/src/components/ExampleFunctionalTransformerHist.cpp and https://github.com/key4hep/k4FWCore/blob/971ae2da7efec5a167b4ab6ecf365c0e27ca41ca/test/k4FWCoreTest/options/ExampleFunctionalTransformerHist.py where in the cpp file you only need to fill the histogram and the exporting gets done by the RootHistSvc.

Is this really wanted/important? I need to access the TH1 to add the overflow bin

[BrieucF]

For histogramming I think that works fine, but since a few days ago there is an example in k4FWCore: https://github.com/key4hep/k4FWCore/blob/971ae2da7efec5a167b4ab6ecf365c0e27ca41ca/test/k4FWCoreTest/src/components/ExampleFunctionalTransformerHist.cpp and https://github.com/key4hep/k4FWCore/blob/971ae2da7efec5a167b4ab6ecf365c0e27ca41ca/test/k4FWCoreTest/options/ExampleFunctionalTransformerHist.py where in the cpp file you only need to fill the histogram and the exporting gets done by the RootHistSvc.

Done

[BrieucF]

@jmcarcell the test related to this PR passes (I removed Event Counter). Shall we handle the other tests in another PR?

[jmcarcell]

In general a different PR is better because then people can look back and understand why the change was done, otherwise they will find this PR...
Another comment is that Associations will have to be updated to Links but this is probably better done at once for the whole repository.