    NET-EVAL:  Evaluate network functions over a grid.

    Net-eval displays the functions defined by a set of networks at a grid
    of points.  Optionally, the functions may instead be used to generate
    target points at random in accordance with the data model.

    Usage:

        net-eval log-file range { / low high grid-size } [ "targets" ]

    The networks are taken from the named log-file, with the specified
    range.  The range has the usual form, "[low][:[high]][%mod]", with
    'high' defaulting to 'low' if the colon is absent, and to the end of
    the file if the colon is present.

    Each group of the remaining arguments describes the grid along one
    input dimension, with 'low' and 'high' being the range of the grid
    along that dimension, and grid-size + 1 being the number of grid
    points spread across that range.  The number of such argument groups
    must be the same as the number of input dimensions.  For survival
    models with non-constant hazard, the time input is included amongst
    these inputs.

    The output consists of a section for each network, with sections
    separated by blank lines.  Each section contains as many lines as
    there are grid points, with each line giving the input values followed
    by the output values.  When there is more than one input variable, a
    blank line is output between groups of points where all but the last
    variable are the same.

    If the final argument is "targets", then rather than writing the
    network outputs, the program instead generates target values from
    these outputs, as defined by the data model.  This option is not
    allowed for survival models, except for those with constant hazard.

    Note that the grid gives the actual values to which the input units
    are set.  Any transformations that may have been specified with
    "data-spec" are ignored.  Similarly, it is the raw output of the
    network (or generated target value) that is displayed, without any
    transformation.

                Copyright (c) 1995-2004 by Radford M. Neal