C Copyright(C) 2011-2017 National Technology & Engineering Solutions of
C Sandia, LLC (NTESS).  Under the terms of Contract DE-NA0003525 with
C NTESS, the U.S. Government retains certain rights in this software.
C 
C Redistribution and use in source and binary forms, with or without
C modification, are permitted provided that the following conditions are
C met:
C 
C * Redistributions of source code must retain the above copyright
C    notice, this list of conditions and the following disclaimer.
C           
C * Redistributions in binary form must reproduce the above
C   copyright notice, this list of conditions and the following
C   disclaimer in the documentation and/or other materials provided
C   with the distribution.
C                         
C * Neither the name of NTESS nor the names of its
C   contributors may be used to endorse or promote products derived
C   from this software without specific prior written permission.
C                                                 
C THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
C "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
C LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
C A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
C OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
C SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
C LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
C DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
C THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
C (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
C OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

C=======================================================================
      SUBROUTINE HUNT(XX,N,X,JLO)
C=======================================================================
      DIMENSION XX(N)
      LOGICAL ASCND
      ASCND=XX(N).GT.XX(1)
      IF(JLO.LE.0.OR.JLO.GT.N)THEN
        JLO=0
        JHI=N+1
        GO TO 3
      ENDIF
      INC=1
      IF(X.GE.XX(JLO).EQV.ASCND)THEN
1       JHI=JLO+INC
        IF(JHI.GT.N)THEN
          JHI=N+1
        ELSE IF(X.GE.XX(JHI).EQV.ASCND)THEN
          JLO=JHI
          INC=INC+INC
          GO TO 1
        ENDIF
      ELSE
        JHI=JLO
2       JLO=JHI-INC
        IF(JLO.LT.1)THEN
          JLO=0
        ELSE IF(X.LT.XX(JLO).EQV.ASCND)THEN
          JHI=JLO
          INC=INC+INC
          GO TO 2
        ENDIF
      ENDIF
3     IF(JHI-JLO.EQ.1)RETURN
      JM=(JHI+JLO)/2
      IF(X.GT.XX(JM).EQV.ASCND)THEN
        JLO=JM
      ELSE
        JHI=JM
      ENDIF
      GO TO 3
      END
