defines the termination conditions, gets a primary from a beam or
from a source and starts the transport
(see also RANDOMIZe, STOP)
WHAT(1) = maximum number of primary histories simulated in the run
Default = 5000.
WHAT(2) = not used
WHAT(3) = time left for termination and printout (in seconds)
Default: 80
WHAT(4) = not used
WHAT(5) = 0.0 : a line reporting the number of calls to the random
number generator (in hexadecimal form) is printed at
the beginning of each history only for the first
ones, and then with decreasing frequency
> 0.0 : the number of calls is printed at the beginning of
each history.
WHAT(6) = time reserved for an interactive run (in seconds)
Default: 100.0
SDUM : not used
Default (option START not given): the other input cards are read
and an echo is printed on the standard output, but no
actual simulation is performed. However two input cards,
both related to geometry, have an effect even if no
START card is present: GEOEND (with SDUM = DEBUG) and
PLOTGEOM.
In all cases in which particles are transported, START
must ALWAYS be present.
Note: The interactive time limit indicated by WHAT(6) can be used
only on some systems which can provide a signal when the time
limit is approaching. On personal workstations, generally no
time limit is enforced.
It is also possible to terminate a FLUKA run before the pre-set
time has expired or the total number of histories has been
completed. To this effect, the user may create a "stopping file"
(its content is irrelevant, since only its existence is checked
by the program).
When the program detects the existence of such a file, the
time left is set to zero, the run is terminated at the end
of the current history, and the stopping file itself is
erased.
The name of the stopping file is FLUKA$STOP on VAX, and
"inputname".stop on UNIX, where "inputname" is the name of
the input file without the extension .inp. The name of the
input file is provided by the user via the option COMMENT
(SDUM = INPUT), otherwise it is assumed to be "fluka" by
default.
Example:
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
START 70000.0
* Request a run of 70000 primary particles
