TPC: use pixel-related readout mode in digitization

• TPCPixelClusteringDigiAlg, based on TPCDigiAlg
  • clustering in digitization, equal to pad mode but with different spatial resolution
  • spatial resolution refers to Chang Yue and ZHAO Guang's full difussion simulation results
  • Because clustering in 10 rows (5mm), the effective electron changed from 30 (6mm) to 25.

mentioned in commit e8ddf31a

merged

Hi @fucd,

Do you duplicate the class definition in both header and implementation files?

@lintao Yes, following your question, I am also aware of better to control through an option like FixelClustering = true/false. I will consider to update it.

A better software design would be introducing Gaudi Tools for the different implementation. If refactor with tools, only one algorithm is needed.

@lintao I agree to use tool. But in this case, only some functions are different for two mode, so I merge them and then set through mode option in !69 (merged) . If more suggestion, please let me know.