User hooks

The user can interface with CMSIM at different stages via a set of ``USER HOOKS.'' The list of these hooks is presented below:
US_FFKEY -- FFREAD control cards and other first initialisations
U_INITG -- initialisations after reading FF cards
U_INITH -- user definition of histograms
U_INITU -- user definition of ntuples
USKINE -- user definition of kinematics called when IKINE = 9 (see control card ``KINE'').
USSTEP -- user action in GUSTEP
USTRIG -- user action in GUOUT to prohibit event output
US_OUT -- user action in GUOUT prior to event i/o
USLAST -- user termination.
There are dummy versions of these routines in the CVS module user. In USTRIG the user sets the variable IEOTRI to non-zero for the event not to be output. The IEOTRI is a GEANT variable in common GCFLAG.

The user can define a set of user ntuples which can be saved in the standard histogram file specified through the CFIL data card:

CFIL 'HBKO' 'cms113.hbook '

The file is opened and saved by the CMSIM program if the user sets the flag through HBOOK data card. If the user does not require the standard CMSIM ntuples, a recommended control flag is

HBOOK 'BEAM' 1

The declaration and the filling of user ntuples should take place in the routines U_INITH and US_OUT respectively with the following controls :

      TUPLE = ICFLAG ('CMSE','HBOOK') .GT. 0
      IF (TUPLE) THEN
        CALL HCDIR ('//PAWC/USER', ' ')
        CALL HCDIR ('//HBKO', ' ')
*
*       Now book CWN's using HBNT, HBNAME, etc.
*
        CALL HCDIR ('//PAWC', ' ')
      ENDIF

in the routine U_INITH and

      TUPLE = ICFLAG ('CMSE','HBOOK') .GT. 0
      IF (TUPLE) THEN
        CALL HCDIR ('//PAWC/USER', ' ')
        CALL HCDIR ('//HBKO', ' ')
*         Fill up the ntuple using HFNT etc
      ENDIF

in the routine US_OUT.