SUBROUTINE SORTIT( X, Y, N, M )
C
C	This subroutine performs a "bubble" sort of the X and the
C	Y values such that the X values are in non-decreasing order
C	with index.
C
C	X	Independent array, dimensioned N.
C	Y	Dependent array, dimensioned N by M.
C	N	Number of values in the X array.
C	M	Number of dependent values associated with
C		each independent array value.
C
	DIMENSION X(N), Y(N,M)
	LOGICAL SORTED
C
C - INITIALIZE FOR THE SORT.
	I = 1
	NSORT = N
	SORTED = .TRUE.
C
C - SWITCH VALUES?
100	IF( X(I+1) .GE. X(I) ) GO TO 200
C
C - SWITCH X VALUES.
	XT = X(I)
	X(I) = X(I+1)
	X(I+1) = XT
C
C - SWITCH Y VALUES.
	DO 1000 J=1,M
	YT = Y(I,J)
	Y(I,J) = Y(I+1,J)
1000	Y(I+1,J) = YT
C
C - REMEMBER THAT VALUES HAVE BEEN SWITCHED, SORT NOT YET DONE.
	LAST = I
	SORTED = .FALSE.
C
C - CONTINUE UNTIL SORTED.
200	I = I + 1
	IF( I .LT. NSORT ) GO TO 100
	IF( SORTED ) RETURN
	I = 1
	NSORT = LAST
	SORTED = .TRUE.
	GO TO 100
	END