BASE110 The system initialisation routines

CALL GZEBRA (NZ)

Initialises the ZEBRA memory manager to use the common /GCBANK/ to store the GEANT data structures.

NZ

( INTEGER) size of the /GCBANK/ common as it is dimensioned in the main program.

CALL GINIT Presets labelled common block variables to default values. See [BASE030] for more information.

CALL GFFGO Reads a set of data records via the FFREAD package. See [BASE040] for more information on the possible data records. GFFGO must be called after GINIT.

CALL GZINIT

Initialises the ZEBRA permanent data structures in division 2 of the GEANT main store in common /GCBANK/. Creates the user long term division (index IXCONS) (minimum size 2000, maximum size 8*NZEBRA/10). The ZEBRA division IXDIV is reserved for the event data structures and the division IXCONS for the initialisation data structures. Allocates 5200 words of working space. Initialises the link areas and a default run header bank JRUNG [BASE299]. Defines banks format for I/O. GZINIT must be called after GFFGO.

A layout of the dynamic store is shown in fig .

Figure: Layout of the dynamic store

CALL GDINIT This routine initialises the GEANT drawing package [DRAW001] and it has to be called before any other graphic routine. GEANT uses the CERN-developed HIGZ [] graphic library, and this has to be initialised before the call to GDINIT. In the example given in [BASE100] the routines IGINIT and IGMETA are used. Alternatively, the routine HPLINT from HPLOT [] can be used. This routine calls the appropriate procedures from HIGZ to initialise the underlaying graphics system. At the moment HIGZ can use several flavours of GKS [,,] and X11 and it is available on all machines where the CERN Program Library has been installed.

CALL GPHYSI Completes the data structure JMATE, (see [PHYS100]) calculating the cross-section and stopping power tables.

CALL GBHSTA Initialises the standard histograms requested by the user via the data record HSTA. The following histogram keywords may be used :

TIME

time per event;

SIZE

size of division IXDIV per event;

MULT

total number of tracks per event;

NTRA

number of long life tracks per event;

STAK

maximum stack size per event.

GBHSTA should be called after GFFGO.

CALL GGCLOS This routine has to be called at the end of the definition of the geometry by the user, after thal all volumes have been defined and positioned and all detectors defined. Failure to call this routine will prevent the GEANT system from working correctly. Main tasks of this routine are:

• close the geometry package;
• complete the JVOLUM data structure;
• process the detector definition provided by the user;
• prepare the tables for the tracking speed optimisation requested by the user via the GSORD routine or the OPTI data record.

BASE200