Rivet tutorials

Analysis options

Some analyses allows the user to interact with them directly on the command line, using so-called options. The options are arguments to analyses given on the commandline (or through the API), which will change the behaviour of the analysis. At a glance, an option is given with the following syntax:

rivet <hepmc-file> -a <analysis-name>:<option-key>=<option-value>

Example: centrality selection for heavy ion analysis

The most prevalent use case for analysis options, is in heavy ion analysis that bin observables in centrality. The user has the option to either select the experimentally measured centrality observables, a user generated one equivalent to that, impact parameter also generated by the user, or a number, which should then be present in the HepMC file. As an example, look at ATLAS_2015_I1360290. It allows the option with key cent to make this selection. So if the user would prefer to stick to the experimentally measured values, the correct syntax would be:

rivet <hepmc-file> -a ATLAS_2015_I1360290:cent=REF

An analysis can be added multiple times, with different values for a given option. Rivet will then treat them as separate analyses. The syntax:

rivet <hepmc-file> -a ATLAS_2015_I1360290:cent=REF -a ATLAS_2015_I1360290:cent=RAW

adds the same analysis twice, with two different selections.