 
      SUBROUTINE JOIN(MM, M, N, A, RLAB, TITLE, DMIWRK, IWORK, WORK,
     *                TLAB, IERR, OUNIT)
C
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C
C   PURPOSE
C   -------
C
C      USES A GENERAL JOINING ALGORITHM TO FORM AND OUTPUT A TREE OF
C      CLUSTERS OF CASES
C
C   DESCRIPTION
C   -----------
C
C   1.  THE VARIABLES MUST BE SCALED SIMILARLY (CLUSTER SUBROUTINE
C       STAND CAN BE USED TO STANDARDIZE THE VARIABLES.)
C
C   2.  INITIALLY, EACH OBJECT IS ASSUMED TO BE A CLUSTER.  THEN THE
C       TWO CLOSEST CLUSTERS ARE AMALGAMATED TO FORM A NEW CLUSTER.
C       THIS PROCESS OF COMBINING THE CLOSEST TWO CLUSTERS CONTINUES
C       UNTIL ONLY ONE CLUSTER REMAINS.  A TREE IS MAINTAINED TO SHOW
C       ALL CLUSTERS AT EACH STEP.
C
C   3.  THE OUTPUT IS THE STANDARD TREE WRITTEN ON FORTRAN UNIT OUNIT.
C       IT LISTS THE CASES VERTICALLY AND HAS HORIZONTAL LINES
C       EMANATING FROM EACH CASE.  EACH CLUSTER WILL CORRESPOND TO A
C       VERTICAL LINE BETWEEN TWO HORIZONTAL LINES.  THE CASES BETWEEN
C       AND INCLUDED IN THE HORIZONTAL LINES ARE THE MEMBERS OF THE
C       CLUSTER.  THE DISTANCE FROM THE CASE NAMES TO THE VERTICAL
C       LINES CORRESPOND TO THE CLUSTER DIAMETER OR THE DISTANCE AT
C       WHICH THE TWO CLUSTERS WERE JOINED.
C
C   INPUT PARAMETERS
C   ----------------
C
C   MM    INTEGER SCALAR (UNCHANGED ON OUTPUT).
C         THE FIRST DIMENSION OF THE MATRIX A.  MUST BE AT LEAST M.
C
C   M     INTEGER SCALAR (UNCHANGED ON OUTPUT).
C         THE NUMBER OF CASES.
C
C   N     INTEGER SCALAR (UNCHANGED ON OUTPUT).
C         THE NUMBER OF VARIABLES.
C
C   A     REAL MATRIX WHOSE FIRST DIMENSION MUST BE MM AND WHOSE SECOND
C            DIMENSION MUST BE AT LEAST N (DESTROYED DURING EXECUTION).
C         THE MATRIX OF DISTANCES BETWEEN CASES.
C
C         A(I,J) IS THE VALUE FOR THE J-TH VARIABLE FOR THE I-TH CASE.
C
C   RLAB  VECTOR OF 4-CHARACTER VARIABLES DIMENSIONED AT LEAST N.
C            (UNCHANGED ON OUTPUT).
C         THE LABELS OF THE CASES.
C
C   TITLE 10-CHARACTER VARIABLE (UNCHANGED ON OUTPUT).
C         TITLE OF THE DATA SET.
C
C   DMIWRK INTEGER SCALAR (UNCHANGED ON OUTPUT).
C         THE FIRST DIMENSION OF THE MATRIX IWORK.  MUST BE AT LEAST 4.
C
C   IWORK INTEGER MATRIX WHOSE FIRST DIMENSION MUST BE DMIWRK AND SECOND
C            DIMENSION MUST BE AT LEAST M.
C         WORK MATRIX.
C
C   WORK  REAL VECTOR DIMENSIONED AT LEAST M.
C         WORK VECTOR.
C
C   TLAB  VECTOR OF 4-CHARACTER VARIABLES DIMENSIONED AT LEAST M+1.
C         WORK VECTOR.
C
C   OUNIT INTEGER SCALAR (UNCHANGED ON OUTPUT).
C         UNIT NUMBER FOR OUTPUT.
C
C   OUTPUT PARAMETER
C   ----------------
C
C   IERR  INTEGER SCALAR.
C         ERROR FLAG.
C
C         IERR = 0, NO ERRORS WERE DETECTED DURING EXECUTION
C
C         IERR = 1, EITHER THE FIRST AND LAST CASES OR THE CLUSTER
C                   DIAMETER FOR A CLUSTER IS OUT OF BOUNDS.  THE
C                   CLUSTER AND ITS VALUES ARE PRINTED ON UNIT OUNIT.
C                   EXECUTION WILL CONTINUE WITH QUESTIONABLE RESULTS
C                   FOR THAT CLUSTER.
C
C   REFERENCES
C   ----------
C
C     HARTIGAN, J. A. (1975).  CLUSTERING ALGORITHMS, JOHN WILEY &
C        SONS, INC., NEW YORK.  PAGES 216-232.
C
C     HARTIGAN, J. A. (1975) PRINTER GRAPHICS FOR CLUSTERING. JOURNAL OF
C        STATISTICAL COMPUTATION AND SIMULATION. VOLUME 4,PAGES 187-213.
C
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