Initialisation

How to Set and Change VINCIA Parameters

VINCIA shares the PYTHIA 8 settings database, which is automatically expanded to include the VINCIA parameters whenever VINCIA is linked. All options and parameters, including the additional VINCIA ones described in this documentation, can therefore be set exactly as in PYTHIA 8, i.e., using

pythia.readString("Vincia:parameter = value");

and/or collections of such strings in a PYTHIA 8 command file,

pythia.readFile("commandFile.cmnd");

where Vincia:parameter can be any of the parameters described in this documentation (all VINCIA parameters are prefaced by Vincia: in order to disambiguate them clearly from PYTHIA ones), and commandFile.cmnd may contain both VINCIA and PYTHIA 8 parameters together (be careful not to overwrite parameters if reading in several command files).

For optimal performance, you should simply give the name of your command file directly as a second argument to the constructor, i.e., replacing the default constructor above by

VinciaPlugin vincia(&pythia,"commandFile.cmnd");

The default value for the command file is "none" in which case no command file is read in by the constructor.

Regardless of whether the name of a command file is given to the constructor or not, (further) commands and command files may of course still be read in after construction, using the methods above. The constructor simply provides an efficient and convenient way of doing it, and adds a bit of extra functionality in the process, such as the possibility of reading in the name of a second command file, containing non-default antenna presets, and processing that file automatically. When bypassing the constructor, this would have to be handled manually.

Initialisation of Default Values

VINCIA initialises its default values from a set of XML files included together with the code. The same XML files are also used to generate this documentation, ensuring consistency between the default code and the documentation (this behaviour is inherited from PYTHIA).

It is strongly discouraged to change any of the XML, HTML, or PHP documentation files directly. Instead, the methods described above, common to PYTHIA 8, should be used to set/modify both PYTHIA and VINCIA parameters. See the section on Installation & Linking if you are suspect you are having problems caused by VINCIA not being able to find the correct location of its XML file set.