Propagate run Parameters from input to output

[andresailer]

BEGINRELEASENOTES

• Add reading of HepMC3 run info and forwarding it to output files: fixes Persist HepMC3 GenRunInfo attributes into metadata tree #1114. Reliably this will only work for HepMC3 >= 3.2.6.

ENDRELEASENOTES

TODO:

• Check that this works
• Make it nicer
• Re-use EventParameters for RunParameter storage? Cannot do that, cannot specialize the ingestParameters function more than once
• Write release notes

[github-actions]

Test Results

       6 files         6 suites   7h 36m 29s ⏱️
   358 tests    358 ✔️ 0 💤 0 ❌
1 058 runs  1 058 ✔️ 0 💤 0 ❌

Results for commit 346b3e0.

♻️ This comment has been updated with latest results.

[andresailer]

As far as I understand, this will only work with HepMC3 >= 3.2.6 https://gitlab.cern.ch/hepmc/HepMC3/-/issues/44

[MarkusFrankATcernch]

@andresailer This issue is highly connectedd to: PR #1140
Are you sure to add parameters as 4 tuples (string, int, float, double) with name-value pairs?
This to me looks quite limiting.
Would it not be better to have predefined xml snippets and then online store maps <string, string> ?
Such snippets could be:

<param name="author-name" type="string"  value="A.Sailer"/>
<param name="generator" type="string"  value="Jetset 8.6"/>
<param name="world-x" type="double" unit="m"  value="30"/>
<param name="world-y" type="double" value="30*m"/>
<param name="center-of-mass-energy" type="energy"  unit="Gev" value="5000.6"/>
<param name="ECAL:encoding" type="encoding"  value="system:8,barrel:3,module:4,layer:6,slice:5,x:32:-16,y:-16"/>
etc.

[andresailer]

Hi Markus, this is related to #1114

I don't understand what you mean though about the 4 tuples.

[MarkusFrankATcernch]

The 4 tuples are:

      std::map<std::string, std::vector<int>>         m_intValues {};
      std::map<std::string, std::vector<float>>       m_fltValues {};
      std::map<std::string, std::vector<std::string>> m_strValues {};
      std::map<std::string, std::vector<double>>      m_dblValues {};

[andresailer]

So it probably also works with hepmc before 3.2.6, but the ReaderAscii only parses the run_info when actually reading events, so we skip(-1), which is otherwise a no-op, I hope also for all the other readers (it is for the Root Reader).

[andresailer]

I think the skip(-1) is not working. I am confused.

[MarkusFrankATcernch]

Negative skips can only work for direct access files (root etc.)
For sequential files this generally is difficult unless one wants to keep a seek entry for every event accessed in the file.

[andresailer]

Negative skips can only work for direct access files (root etc.) For sequential files this generally is difficult unless one wants to keep a seek entry for every event accessed in the file.

I thought the reader would parse all the text until it hits an event but not the event, but I misread the code and the (-1) was exiting even earlier.

https://gitlab.cern.ch/hepmc/HepMC3/-/blob/92f12d3d2af65c2e142c164fe3d7bed77aa766cc/src/ReaderAscii.cc#L54

Now I read an event and then create a new reader with the same file. How bad can this be 🤔

[MarkusFrankATcernch]

No. Look. This cannot be. If we made a design error we should correct it.

[andresailer]

It is a problem with the hepmc reader, not in dd4hep.

[andresailer]

Apparently, segfault is how bad this can be, so back to the drawing board.

[andresailer]

The segfault was due to moving the reader creation to the beginRun only. But the tests were directly calling readparticles, without there being beginRun. Now a reader is created either at begin run, or in readParticles (as before).

Added also a HepMC Version check so that the code should compile...

[andresailer]

As far as I am concerned, this is as good as it gets for the moment.