cms-sw/cmssw — pull request #4541 by mark-grimes (2014-07-07 08:41:31+00:00)
Title: Remap forward pixel DetIds in files from from old CMSSW versions

The DetId numbering in the forward pixel discs changed when going from SLHC12->SLHC13. The ability to read SLHC11 files is still required because the production GEN-SIM for the Technical Proposal was made with SLHC11.
This fix checks the version of CMSSW the input SimHit collection was made with. If it is SLHC11 or SLHC12 the DetIds are remapped to the new numbering scheme. If it is anything else the collection is left alone.

Plots below when running on the SLHC production samples, QCD with 140 pileup:

In both cases blue is with this fix, red is normal SLHC14 running on the SLHC11 files.

**Number of pixel endcap layers per track**
![numberofpixendcaplayerspertrackvseta](https://cloud.githubusercontent.com/assets/6480160/3492926/412547be-05b2-11e4-8a33-ee1af9a6ceae.png)

**Number of RecHits per track**
![goodtracknumberoffoundrechitspertrackvseta](https://cloud.githubusercontent.com/assets/6480160/3492929/4646b796-05b2-11e4-81e9-d068d38ba8c9.png)