    BVG-SPEC:  Specify a bivariate Gaussian distribution to sample from.

    BVG-spec creates a log file with a record specifying a bivariate
    Gaussian distribution, or displays the specification in an existing
    log file.

    Usage:

       bvg-spec log-file std1 std2 corr [ replication ]

    or:

       bvg-spec log-file

    When called with arguments other than a log file name, it creates a
    log file of that name, and stores in it the standard deviations of the
    bivariate Gaussian along the two axes, and the correlation of the two
    axes.

    The optional replication argument results in a multivariate Gaussian
    distribution obtained by creating that number of independent bivariate
    Gaussian variables.

    When called with only the log file as an argument, the program reads
    this record from an existing log file and displays the values stored.

    The specifications are stored in the log file as a single record of
    type 'B' and index -1,

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