Additional info, in EvtVector4C I had to add two more copies of multiplication operator between EvtVector4C and complex number, the constructor from EvtComplex and set methods working with EvtComplex and doubles (otherwise call with doubles would be ambiguous as conversion to both complex numbers is possible).

There is no way of grabbing decay tables from PDG at this moment. PDG data are not defined well enough to be able to simply read them in an automated way and in places looking up details in the original papers is needed to understand the exact meaning. Also, measurements can be conflicting and such cases need to be resolved by hand anyhow. There were attempts before and they failed and introduced mistakes that were not immediately obvious.

• Add change to History.md

• Rename member variables starting with underscore to m_xxx
• Rename variables ending on underscore in EvtGenBase and small cleanup from previous chunk
• Next part of renaming member variables finishing with underscore.
• Rename preprocessor macro from _unused to UNUSED

• Rename preprocessor macro from _unused to UNUSED

I think I have it now all, but I ran to another issue with arcanist, which refused to upload diff on a large file without marking it binary. The file is src/EvtGenModels/EvtVubAC.cpp and we might need to change it back from binary when we finish this.

• Rename member variables starting or ending with underscore to m_xxx

All looks fine to me.

In following pdf I compare old code and new version for pi0 --> e+e-gamma, eta --> e+e-gamma and eta -- > mu+mu-gamma. In comparison, old code uses artificially increased maximum probability. Nothing changes on the q2 distribution to the point that the two distributions are hard to distinguish.

It all looks good to me. I note that you have shuffled things in README a little bit and it makes sense, but we will need to write a few words in the introduction. Perhaps we can adapt things from the introduction of the guide, but I would be happy to land this and add an introduction in README in another step.

• Few small improvements in coding style thanks to Tom

I did run test after all changes and the distribution is still nicely flat. I think it should be ready to go.

• Cleanup of few formulas to be more transparent and fix formatting

@jback, I think you are still compiling with C++11 using old build system. We will need CMake as soon as we are removing EvtGen from LHCb repository, so lets review Tom's changes for that and merge that into master. Then we can rebase modernize branch from master to get CMake build system into it and by that it should be basically automatic as Tom put at least C++14 into that.

@jback, which version of g++ you use? I think we might need at least C++14 for code changes Gerhard did. Using g++ 6.2 should work, g++ 4 will definitely not.