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2\section{File Reading\label{TAPE}}
3
4 The FORTRAN instruction
5\begin{verbatim}
6 CALL RDTAPE(IDEV,IFL)
7\end{verbatim}
8will read a beginning record, an end record or an event (which can be
9more than one record). IDEV is the tape number and
10\begin{verbatim}
11 IFL=0 for a good read,
12 IFL=-1 for an end of file.
13\end{verbatim}
14The information is restored to the common blocks described above. The
15type of record is contained in
16\begin{verbatim}
17#include "rectp.inc"
18\end{verbatim}
19\begin{tabular}{lcl}
20IRECTP &=& 100 for an event record\\
21IRECTP &=& 200 for a beginning record\\
22IRECTP &=& 300 for an end record\\
23IREC &=& no. of physical records in event record, 0
24 otherwise\\
25\end{tabular}
26
27 The parton momenta from the primary hard scattering are
28contained in /PJETS/. The parton momenta generated by the QCD cascade
29are contained in /JETSET/. The hadron momenta both from the QCD jets
30and from the beam jets are contained in /PARTCL/. The final hadron
31momenta and the associated pointers should be used to calculate the
32jet momenta, since they are changed both by the QCD cascade and by
33hadronization. Particles with IDCAY=0 are stable, while the others are
34resonances.
35
36 The weight per event needed to produce a weighted histogram in
37millibarn units is SIGF/NEVENT. The integrated cross section SIGF is
38calculated by Monte Carlo integration during the run for the given
39kinematic limits and JETTYPE, WTYPE, and WMODE selections. Any of three
40methods can be used to find the value of SIGF:
41
42 (1) The current value, which is written out with each event, can
43be used. To prevent enormous fluctuations at the beginning of a run,
44NSIGMA extra primary parton events are generated first. The default
45value, NSIGMA = 20, gives negligible overhead but may not be large
46enough for good accuracy.
47
48 (2) The value SIGF calculated with the full statistics of the run
49can be obtained by reading through the tape until an end record
50(IRECTP=300) is found. After SIGF is saved with a different name, the
51first event record for the run can be found by backspacing the tape
52NRECS times.
53
54 (3) Unweighted histograms can be made for the run and the weight
55added after the end record is found. An implementation of this using
56special features of HBOOK is contained in ISAPLT.
57
58 The functions AMASS(IDENT), CHARGE(IDENT), and LABEL(IDENT) are
59available to determine the mass, charge, and character label in A8
60format. Subroutine FLAVOR returns the quark content of any hadron and
61may be useful to convert IDENT codes to other schemes. CALL PRTEVT(0)
62prints an event.