    XXX-MC:  Run Markov chain simulation.

    There is a version of this program for each 'mc' application (eg,
    net-mc).  The version of this program for a given application runs a
    Markov chain simulation, using the application-specific routines for
    that application, as specified in a previous call of 'mc-spec'.

    Usage:

        xxx-mc [ -c coupled-log-file ] log-file ["@"]iteration [ save-mod ]
               [ quantities | "tt[12]" ] [ / decay [ temperature ] ]

    Here 'xxx' is a prefix identifying the particular incarnation of this
    program.

    This program performs a Markov chain Monte Carlo simulation starting
    with the last iteration saved in log-file and continuing up to the
    indicated iteration (or if the iteration is immediately preceded by
    "@", until a total of iteration minutes of cpu-time have been used,
    for all iterations).  The log file must contain specifications for how
    to run the simulation, as created by mc-spec; the last such in the log
    file is used.  Results of the simulation are appended to the log file
    for iterations that are divisible by save-mod, which defaults to one
    (every iteration saved).

    The 'quantities' parameter specifies what is to be printed on standard
    output when 'plot' specifications are encountered.  The default is
    nothing.  If "tt1" or "tt2" are specified, the progress of tempered
    trajectories and tempered transitions is plotted, the details
    depending on the digit (you'll have to look at the program code to
    learn more).

    If a decay parameter is specified, it overrides the decay parameter in
    the specification of any "heatbath" operations.  The temperature
    parameter controls the level of noise added in heatbath operations and
    the acceptance test for metropolis and hybrid updates, and may also
    affect application specific updates.  It defaults to one.  (Note that
    this temperature is not the same as any temperature involved in
    tempering operations.)

    The -c option is used when the simulation is "coupled" to a previously
    performed simulation, whose results are stored in coupled-log-file.
    It causes the simulation to be terminated if and when the iteration
    written to log-file exactly matches the corresponding iteration in
    coupled-log-file, ignoring the records of type "i" that record the
    iteration statistics.  When this situation is detected, the remaining
    iterations to be performed are simply copied from coupled-log-file to
    log-file.  The "k" quantity (normally cumulative compute time) will be
    set to -1e-4 for such copied iterations.  Coupling is not allowed if
    the number of iterations to do is specified by a time limit rather
    than a maximum iteration number.

                Copyright (c) 1995-2003 by Radford M. Neal