SLATEC Routines --- QS2I1D ---

*DECK QS2I1D
      SUBROUTINE QS2I1D (IA, JA, A, N, KFLAG)
C***BEGIN PROLOGUE  QS2I1D
C***SUBSIDIARY
C***PURPOSE  Sort an integer array, moving an integer and DP array.
C            This routine sorts the integer array IA and makes the same
C            interchanges in the integer array JA and the double pre-
C            cision array A.  The array IA may be sorted in increasing
C            order or decreasing order.  A slightly modified QUICKSORT
C            algorithm is used.
C***LIBRARY   SLATEC (SLAP)
C***CATEGORY  N6A2A
C***TYPE      DOUBLE PRECISION (QS2I1R-S, QS2I1D-D)
C***KEYWORDS  SINGLETON QUICKSORT, SLAP, SORT, SORTING
C***AUTHOR  Jones, R. E., (SNLA)
C           Kahaner, D. K., (NBS)
C           Seager, M. K., (LLNL) seager@llnl.gov
C           Wisniewski, J. A., (SNLA)
C***DESCRIPTION
C     Written by Rondall E Jones
C     Modified by John A. Wisniewski to use the Singleton QUICKSORT
C     algorithm. date 18 November 1976.
C
C     Further modified by David K. Kahaner
C     National Bureau of Standards
C     August, 1981
C
C     Even further modification made to bring the code up to the
C     Fortran 77 level and make it more readable and to carry
C     along one integer array and one double precision array during
C     the sort by
C     Mark K. Seager
C     Lawrence Livermore National Laboratory
C     November, 1987
C     This routine was adapted from the ISORT routine.
C
C     ABSTRACT
C         This routine sorts an integer array IA and makes the same
C         interchanges in the integer array JA and the double precision
C         array A.
C         The array IA may be sorted in increasing order or decreasing
C         order.  A slightly modified quicksort algorithm is used.
C
C     DESCRIPTION OF PARAMETERS
C        IA - Integer array of values to be sorted.
C        JA - Integer array to be carried along.
C         A - Double Precision array to be carried along.
C         N - Number of values in integer array IA to be sorted.
C     KFLAG - Control parameter
C           = 1 means sort IA in INCREASING order.
C           =-1 means sort IA in DECREASING order.
C
C***SEE ALSO  DS2Y
C***REFERENCES  R. C. Singleton, Algorithm 347, An Efficient Algorithm
C                 for Sorting With Minimal Storage, Communications ACM
C                 12:3 (1969), pp.185-7.
C***ROUTINES CALLED  XERMSG
C***REVISION HISTORY  (YYMMDD)
C   761118  DATE WRITTEN
C   890125  Previous REVISION DATE
C   890915  Made changes requested at July 1989 CML Meeting.  (MKS)
C   890922  Numerous changes to prologue to make closer to SLATEC
C           standard.  (FNF)
C   890929  Numerous changes to reduce SP/DP differences.  (FNF)
C   900805  Changed XERROR calls to calls to XERMSG.  (RWC)
C   910411  Prologue converted to Version 4.0 format.  (BAB)
C   910506  Made subsidiary to DS2Y and corrected reference.  (FNF)
C   920511  Added complete declaration section.  (WRB)
C   920929  Corrected format of reference.  (FNF)
C   921012  Corrected all f.p. constants to double precision.  (FNF)
C***END PROLOGUE  QS2I1D