Help for IBISCLST2

PURPOSE:

"IBISCLST2" is a VICAR applications program that reads an IBIS file
containing (x, y) points and calculates clusters for them. Cluster
membership means that a point is within a specified radial distance
from at least one of the other cluster members.

The input file must include the (x, y) point position and an extra
column for storing the cluster ID. The position values are read from
the input IBIS file as double-precision floats. The cluster ID is an
integer, but is written as a double-precision float.

EXECUTION:

    IBISCLST2 INP=IFILE DISTANCE=DIST XCOL=X YCOL=Y CLUSTCOL=CLST

where

    INP  is the input IBIS file that will be modified
    DIST is the maximum point-cluster distance
    X    is the column of point x-values
    Y    is the column of point y-values
    CLST is the column for storing the cluster ID

PERFORMANCE:

The clustering algorithm calculates distances between point pairs
until cluster membership is discovered, possibly calculating all
point pairs when there are no multi-point clusters. So the 
complexity is O(n^2).

WRITTEN BY:  W. Bunch 2016-06-06

COGNIZANT PROGRAMMER: W. Bunch

REVISIONS:  
    2016-06-06 WLB - Initial version.
    2016-06-16 WLB - Changed input IBIS types to DOUB.