    GP-GEN:  Generate GP hyperparameters randomly from the prior, or fix them.

    Gp-gen writes a series of independently-generated values for the
    hyperparameters of a Gaussian process model to a log file.

    Usage:

        gp-gen log-file [ max-index ] [ "fix" [ scale-value relevance-value ] ]

    Records of hyperparameters with indexes from zero up to the indicated
    index are generated (the default is max-index of zero).  If the log
    file already contains records with some of these indexes, only records
    with indexes greater than the last existing record are generated.

    If just max-index is specified, the hyperparameters are generated
    randomly from the prior, using the random number seed taken from the
    log file (eg, as specified by rand-seed).

    The "fix" option is useful for initializing iterative programs.  If it
    is given, the hyperparameters are not generated at random, but are
    instead set to fixed values.  These values are the top-level widths
    for each hyperparameter if no values follow "fix".  If values do
    follow "fix", they specify the scale and relevance hyperparameters of
    exponential parts of the covariance.  The hyperparameters for the
    linear part are set to the product of these two values.  The
    hyperparameter for the constant part is set to the scale value given.

    No data model is required to use gp-gen, but if a model is specified,
    the hyperparameters associated with it are generated as well.

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