$IBFTC FIND.
      SUBROUTINE FIND (X,ISIZE,Y,J1,J2)
      DIMENSION X(ISIZE)
C
C     ONE DIMENSIONAL ARRAY SEARCH SUBROUTINE.  J1 AND J2 ARE
C     SUBSCRIPTS OF X SUCH THAT X(J1).LE.Y.LE.X(J2).
C
      J1=1
      J2=ISIZE
    1 IF(J2-J1.LE.1) RETURN
      J=(Y-X(J1))/(X(J2)-X(J1))*FLOAT(J2-J1)+FLOAT(J1)
      IF(J.EQ.J1.OR.J.EQ.J2) GO TO 6
      IF(J.LT.J1.OR.J.GT.J2) GO TO 7
    2 IF(Y-X(J)) 3,5,4
    3 J2=J
      GO TO 1
    4 J1=J
      GO TO 1
    5 J1=J
      J2=J
      RETURN
    6 J=(J1+J2)/2
      GO TO 2
    7 J2=-J2
      J1=-J1
      RETURN
      END