4.2.4 SUBROUTINE ZEUGEN(I, STEER, IERR) : User GENerator, External read version.

User event generator routine, External read version. The routine reads the contents of the LUJETS common block from the external file unit=STEER(2,11). It will return IERR=-2 (=> stop run) when the end of the file is found. The file should have been written by doing :

WRITE (LUNIT) + N,((K(I,J),J=1,5),(P(I,J),J=1,5),(V(I,J),J=1,5),I=1,N)

for each generated event. Note that the read/write is un-formatted => don't try to write under one system, read under another !

ARGUMENTS:

INPUT :

    I : Current event number.
    STEER : Steering info. The event generator uses row 2:
                  STEER(2,0)   : Type of event to be generated.
                         ,1)   : CMS energy of reaction to be simulated.
                         ,2)   : Lifetime of B hadrons.
                         ,4)   : 0.0 -> use fixed primary vertex position.
                                 1,0 -> generate primary vertex position.
                                        event by event.
                         ,5-7) : Average production point.
                         ,8-10): Spread in production-point.
                         ,11)  : Unit to read LUJETS from
                 All other position of the row are free to use.

    IERR  : error code.

IMPLICIT INPUTS:

     From unit STEER(2,11) : the LUJETS contents.
     From /ZXSTE/ : LUNPRC, printing unit; MAXPR, max number of
          events to print; NEWAMV, flag to load average mean vertex.

IMPLICIT OUTPUTS:

     To /ZXEVT/ : XYZV, average vertex position; SIGV, vertex error;
       EVTYPE, type of generated event.
     To /LUJETS/ : event record in JETSET conventions. This routine
       will directly modify the production points of tracks (vector
       V in LUJETS), and the history code (vector K in LUJETS).

CALLED BY :

ZXCEST, Create the Event STructure (see 4.1.5).

CALLED ROUTINE(S):

LULIST

(JETSET routine.)

ZEPVTX (see 4.2.7)

(To generate Primary VerTeX.)

UCOPY

(CERNLIB routine.)

SIDE EFFECTS:

none.

AUTHORS:

M. Berggren, IPN Lyon

CREATION DATE:

17-FEB-1998