SUBROUTINE SORT ( A, II, JJ )

c*********************************************************************72
c
cc SORT sorts an array into increasing order.
c
C  SORTS ARRAY A INTO INCREASING ORDER, FROM A(II) TO A(JJ).
C  ORDERING IS BY INTEGER SUBTRACTION, THUS FLOATING POINT
C  NUMBERS MUST BE IN NORMALIZED FORM.
C  ARRAYS IU(K) AND IL(K) PERMIT SORTING UP TO 2**(K+1)-1 ELEMENTS.
C
      IMPLICIT NONE

      INTEGER A(*)
      INTEGER I
      INTEGER II
      INTEGER IJ
      INTEGER IL(16)
      INTEGER IU(16)
      INTEGER J
      INTEGER JJ
      INTEGER K
      INTEGER L
      INTEGER M
      INTEGER T
      INTEGER TT

      M = 1
      I = II
      J = JJ
5     IF ( I .GE. J ) GO TO 70
10    K = I
      IJ = ( J + I ) / 2
      T = A(IJ)
      IF ( A(I) .LE. T ) GO TO 20
      A(IJ) = A(I)
      A(I) = T
      T = A(IJ)
20    L = J
      IF ( A(J) .GE. T ) GO TO 40
      A(IJ) = A(J)
      A(J) = T
      T = A(IJ)
      IF ( A(I) .LE. T ) GO TO 40
      A(IJ) = A(I)
      A(I) = T
      T = A(IJ)
      GO TO 40
30    A(L) = A(K)
      A(K) = TT
40    L = L - 1
      IF ( A(L) .GT. T ) GO TO 40
      TT = A(L)
50    K = K + 1
      IF ( A(K) .LT. T ) GO TO 50
      IF ( K .LE. L ) GO TO 30
      IF ( L - I .LE. J - K ) GO TO 60
      IL(M) = I
      IU(M) = L
      I = K
      M = M + 1
      GO TO 80
60    IL(M) = K
      IU(M) = J
      J = L
      M = M + 1
      GO TO 80
70    M = M - 1
      IF ( M .EQ. 0 ) RETURN
      I = IL(M)
      J = IU(M)
80    IF ( J - I .GE. II ) GO TO 10
      IF ( I .EQ. II ) GO TO 5
      I = I - 1
90    I = I + 1
      IF ( I .EQ. J ) GO TO 70
      T = A(I+1)
      IF ( A(I) .LE. T ) GO TO 90
      K = I
100   A(K+1) = A(K)
      K = K - 1
      IF ( T .LT. A(K) ) GO TO 100
      A(K+1) = T
      GO TO 90
      END