C**********************************************************************
C
SUBROUTINE SHPSRT (N,X,Y,Z)
C
C Purpose:
C This subroutine sorts the array X using HeapSort. It rearranges
C the elements of Y and Z at the same time.
C
C Parameters:
C N = the length of the arrays (input).
C X = the primary array to be used in sorting (input/output).
C Y = another array, sorted in the same order as X (input/output).
C Z = another array, sorted in the same order as X (input/output).
C
C Noel M. Nachtigal
C October 4, 1990
C
C**********************************************************************
C
INTEGER N
REAL X(N), Y(N), Z(N)
C
C Local variables.
C
INTEGER I, J, K, L
REAL TMPX, TMPY, TMPZ
C
IF (N.LE.1) RETURN
C
L = N / 2 + 1
K = N
10 IF (L.GT.1) THEN
L = L - 1
TMPX = X(L)
TMPY = Y(L)
TMPZ = Z(L)
ELSE
TMPX = X(K)
TMPY = Y(K)
TMPZ = Z(K)
X(K) = X(1)
Y(K) = Y(1)
Z(K) = Z(1)
K = K - 1
IF (K.LE.1) THEN
X(1) = TMPX
Y(1) = TMPY
Z(1) = TMPZ
RETURN
END IF
END IF
I = L
J = L + L
20 IF (J.LE.K) THEN
IF (J.LT.K) THEN
IF (X(J).GT.X(J+1)) J = J + 1
END IF
IF (TMPX.GT.X(J)) THEN
X(I) = X(J)
Y(I) = Y(J)
Z(I) = Z(J)
I = J
J = J + J
ELSE
J = K + 1
END IF
GO TO 20
END IF
X(I) = TMPX
Y(I) = TMPY
Z(I) = TMPZ
GO TO 10
END
C
C**********************************************************************