SRC-SPEC:  Specify priors of the number and location of sources.

Src-spec is the first command used when specifying a source location
model.  It creates a log file with a record specifying priors for the
number and location of sources.  It can also be used to display the
specifications in an existing log file.

Usage:

  src-spec log-file 
    lowN[:highN] lowQ[:highQ[:power]] 
      [ max-start [ max-stop ] ] [ +max-duration ] 
        / lowx:highx [ lowy:highy [ lowz:highz ] ]

or:

  src-spec log-file

The first form above creates a log file with the name given as the
first argument, and writes specifications to it (destroying any
previous contents of this log file).  The second form displays the
specifications in the log file named.

The number of sources is specified after the name of the log file.
This may be a single integer (from 0 up), or it may be a range of
integers separated by a colon.  If a range is given, the prior is
currently assumed to be uniform over integers in this range.

The next argument is the range of source intensities, which must be
non-negative.  If lowQ and highQ are equal (the default if highQ is
omitted), the source intensities are fixed at this value.  If no
"power" option is given, the prior for the intensity of a source is
assumed to be uniform over this range.  If a power (which must be
positive) is specified, the intensity raised to that power has a
uniform distribution.  This is equivalent to the density for the 
intensity, Q, being proportional to Q^{power-1}.

If the flow model is not steady-state, sources are active only between
some start time and some stop time, both of which are non-negative.
The optional max-start argument gives the latest time that a source
may start.  The prior for the start time of a source is assumed to be
uniform from zero to max-start.  If max-start is omitted, zero is
assumed (so the start times for all sources are fixed at zero).  The
max-stop argument gives the maximum time at which a source may stop.
The max-duration argument (which must start with "+") gives the
maximum allowed duration for a source (stop time minus start time).
The prior for the stopping time of a source given its start time is
uniform from the start time to the maximum allowed by the max-stop and
max-duration arguments.  If max-stop and max-duration are both
omitted, sources never stop being active once they start.  For steady
state models, max-start, max-stop, and max-duration should not be
specified.

Following a "/" argument, the ranges for the locations of the sources
are given, as low:high pairs for x, y, and z.  Here, lowx, lowy,
highx, and highy can be any real numbers.  For the height coordinate
(z), lowz and highz must be non-negative.  The prior for source
locations is assumed to be uniform over the specified ranges.  If the
later ranges are omitted, they are assumed to be 0:0.

            Copyright (c) 2007 by Radford M. Neal