!!Generating results ([@c]simulate, [@c]collect)

After the simulation parameters with their values are defined, simulation and/or
collect runs may be done.

SimTree starts as many instances of the simulation program for different
simulation parameters or for parallel runs as there are process slots
defined on the command line. Process slots may be local (on the machine where
SimTree is started) or remote (on machines on the net which must have mounted
the same file system as the machine where SimTree is started). SimTree fills
the defined slots as long as there are more simulations to run.

Before starting a simulation run, a parameter file is created for this simulation
run. Base of the parameter file is the parameter file template. The the template
there may be replacement pattern of the form %%<Replacement>%%. SimTree replaces
the replacements from two sources:

* When the <Replacement> is the name of of simulation parameter the actual value
  of this simulation parameter is used as replacement.
  
* When an optional attributes file exists, the content of this attribites file
  is used for additional replacements.
  
Before using the so generated parameter file it is checked that no unreplaced
sequences of the form %%<Replacement>%% are remaining.

A simulation program may also be a script which itself executes the real
binary. This is required i.e. for Java based simulation programs where the
script calls the Java virtual machine.
