Procedure

     ORDERD ( Order of a double precision array )

     SUBROUTINE ORDERD ( ARRAY, NDIM, IORDER )

Abstract

     Determine the order of elements in a double precision array.

Required_Reading

     None.

Keywords

     ARRAY
     SORT

Declarations

     IMPLICIT NONE

     DOUBLE PRECISION   ARRAY  ( * )
     INTEGER            NDIM
     INTEGER            IORDER ( * )

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     ARRAY      I    Input array.
     NDIM       I    Dimension of ARRAY.
     IORDER     O    Order vector for ARRAY.

Detailed_Input

     ARRAY    is the input array.

     NDIM     is the number of elements in the input array.

Detailed_Output

     IORDER   is the order vector for the input array.
              IORDER(1) is the index of the smallest element
              of ARRAY; IORDER(2) is the index of the next
              smallest; and so on.

Parameters

     None.

Exceptions

     Error free.

     1)  A negative input dimension causes this routine to leave the
         output order vector unchanged.

Files

     None.

Particulars

     ORDERD finds the index of the smallest element of the input
     array. This becomes the first element of the order vector.
     The process is repeated for the rest of the elements.

     The order vector returned by ORDERD may be used by any of
     the REORD routines to sort sets of related arrays, as shown
     in the example below.

Examples

     In the following example, the ORDER and REORD routines are
     used to sort four related arrays (containing the names,
     masses, integer ID codes, and visual magnitudes for a group
     of satellites). This is representative of the typical use of
     these routines.

            C
            C     Sort the object arrays by visual magnitude.
            C
                  CALL ORDERD ( VMAGS,  N, IORDER )

                  CALL REORDC ( IORDER, N, NAMES )
                  CALL REORDD ( IORDER, N, MASSES )
                  CALL REORDI ( IORDER, N, CODES )
                  CALL REORDR ( IORDER, N, VMAGS )

Restrictions

     None.

Literature_References

     None.

Author_and_Institution

     N.J. Bachman       (JPL)
     J. Diaz del Rio    (ODC Space)
     W.L. Taber         (JPL)
     I.M. Underwood     (JPL)

Version

    SPICELIB Version 1.1.0, 04-JUL-2021 (JDR)

        Edited the header to comply with NAIF standard.

    SPICELIB Version 1.0.2, 23-MAR-2010 (NJB)

        Header example was updated to show use of this routine.
        $Exceptions section was updated. Header sections were
        re-ordered.

    SPICELIB Version 1.0.1, 10-MAR-1992 (WLT)

        Comment section for permuted index source lines was added
        following the header.

    SPICELIB Version 1.0.0, 31-JAN-1990 (IMU)