NAME:			Volstat - Volume Statistics

AUTHOR INFO:	Ian J. Curington
                Stardent Computer Limited
                15 Frederick Sanger Road
                The Surrey Research Park
                Guildford
                Surrey    GU2 5YD
                United Kingdom
                +44-483-505388
                email: ianc@Stardent.COM

SOURCE FILE:	volstat.f

TYPE:			renderer

INPUTS:			field 3d uniform scalar float

OUTPUTS:		formatted numerical text to standard-output

PARAMETERS:     None.

DESCRIPTION:
    Volstat is a diagnostic and analysis module, used to obtain global
statistical information about scalar volume data. Often the result of
numerical analysis and visualization leads to an interest in just a few
numbers such as the average value in the field.

This "volume statistics" module scans the data in the volume,
and produces a small table, sent to stdout, usually into the
window where avs was invoked, unless redirected. The table
shows the dimensional size of the field, total number of data points,
the minimum and maximum scalar values, and the mean. This is a very
simple module, and could be extended to measure other parameters
such as standard deviation, median, etc.

This module does virtually no computationally intensive work, has no
parameters.  The author has used this for debugging other networks
and filters, by linking it in with a "t" junction to other more
complex networks. In particular, when using "interpolate", it is nice
to know the resulting volume dimensions.


EXAMPLE: This network is a demonstration  usage of the volstat module.


    +------------------------+
    |     READ VOLUME        |
    +------------------------+
            |
    +------------------------+
    |    FIELD to FLOAT      |
    +------------------------+
            |
    +------------------------+
    |    Threshold           |
    +------------------------+
            |
    +------------------------+
    |  Volume Statistics     |
    +------------------------+

The result of volstat to standard output is a table like:

 ============= volume statistics ============
 === Dimensions:        100    100     50
 === Total Size:          500000
 === Field Minimum:          0.
 === Field Maximum:    255.0000
 === Field Mean:       2.482354
 ============================================