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: http://theory.sinp.msu.ru/comphep_html/tutorial/node43.html
Дата изменения: Tue Aug 15 14:26:38 2000 Дата индексирования: Mon Oct 1 22:43:43 2012 Кодировка: |
The procedure of event generation consists of two steps. During the evaluation of cross section by Vegas CompHEP writes down the calculated squared matrix elements into a binary file events_N, where N is the session number. These files are compact owing to occupation of approximately four bytes per one event. All CompHEP settings and a current state of the random number generator are stored there too.
On the next step stand-along command genEvents restores the event flow based on this file. It repeats the Vegas session, but instead of the real matrix element evaluation it reads the corresponding values from the file. This trick allows one to repeat with a high speed the calculation of particle momenta and event weights produced earlier during the original Monte Carlo integration.
Note that the CompHEP generates the partonic level events. CompHEP passes the task of fragmentation to other programs like PYTHIA [Sjostrand-1994].