Procedure

     SETD ( Compare double precision sets )

     LOGICAL FUNCTION SETD ( A, OP, B )

Abstract

     Compare two double precision sets, as indicated by a relational
     operator.

Required_Reading

     CELLS
     SETS

Keywords

     CELLS
     SETS

Declarations

     IMPLICIT NONE

     INTEGER                    LBCELL
     PARAMETER                ( LBCELL = -5 )

     DOUBLE PRECISION  A      ( LBCELL:* )
     CHARACTER*(*)     OP
     DOUBLE PRECISION  B      ( LBCELL:* )

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     A          I   First set.
     OP         I   Comparison operator.
     B          I   Second set.

     The function returns the result of the comparison: A (OP) B.

Detailed_Input

     A        is a set.


     OP       is a comparison operator, indicating the way in
              which the input sets are to be compared. OP may
              be any of the following:

                  Operator             Meaning
                  --------  -------------------------------------
                    '='     A = B is .TRUE. if A and B are equal
                            (contain the same elements).

                    '<>'    A <> B is .TRUE. if A and B are not
                            equal.

                    '<='    A <= B is .TRUE. if A is a subset of B.

                    '<'     A < B is .TRUE. if A is a proper subset
                            of B.

                    '>='    A >= B is .TRUE. if B is a subset of A.

                    '>'     A > B is .TRUE. if B is a proper subset
                            of A.

                    '&'     A & B is .TRUE. if A and B have one or
                            more elements in common. (The
                            intersection of the two sets in
                            non-empty.)

                    '~'     A ~ B is .TRUE. if A and B are disjoint
                            sets.

     B        is a set.

Detailed_Output

     The function returns the result of the comparison: A (OP) B.

Parameters

     None.

Exceptions

     1)  If the set relational operator is not recognized, the error
         SPICE(INVALIDOPERATION) is signaled.

Files

     None.

Particulars

     None.

Examples

     1) In the following example, SETx is used to repeat an operation
        for as long as the integer set FINISHED remains a proper
        subset of the integer set PLANNED.

           DO WHILE ( SETx ( FINISHED, '<', PLANNED ) )
              .
              .
           END DO


     2) In the following example, let the integer sets A, B, and C
        contain the elements listed below. Let E be an empty integer
        set.

             A        B        C
           ---      ---      ---
             1        1        1
             2        3        3
             3
             4

     Then all of the following expressions are true.

           SETI ( B, '=',  C )      "B is equal to C"
           SETI ( A, '<>', C )      "A is not equal to C"
           SETI ( A, '>',  B )      "A is a proper superset of B"
           SETI ( B, '<=', C )      "B is a subset of C"
           SETI ( C, '<=', B )      "C is a subset of B"
           SETI ( A, '<=', A )      "A is a subset of A"
           SETI ( E, '<=', B )      "E is a subset of B"
           SETI ( E, '<',  B )      "E is a proper subset of B"
           SETI ( E, '<=', E )      "E is a subset of E"
           SETI ( A, '&',  B )      "A has elements in common with B."
           SETI ( B, '&',  C )      "B has elements in common with C."

     And all of the following are false.

           SETI ( B, '<>',  C )      "B is not equal to C"
           SETI ( A, '=',   C )      "A is equal to C"
           SETI ( A, '<',   B )      "A is a proper subset of B"
           SETI ( B, '<',   C )      "B is a proper subset of C"
           SETI ( B, '>=',  A )      "B is a superset of A"
           SETI ( A, '>',   A )      "A is a proper superset of A"
           SETI ( E, '>=',  A )      "E is a superset of A"
           SETI ( E, '<',   E )      "E is a proper subset of E"
           SETI ( A, '~',   B )      "A and B are disjoint sets."

Restrictions

     None.

Literature_References

     None.

Author_and_Institution

     J. Diaz del Rio    (ODC Space)
     H.A. Neilan        (JPL)
     W.L. Taber         (JPL)
     I.M. Underwood     (JPL)

Version

    SPICELIB Version 1.2.0, 20-AUG-2021 (JDR)

        Added IMPLICIT NONE statement.

        Edited the header to comply with NAIF standard.

    SPICELIB Version 1.1.0, 17-MAY-1994 (HAN)

        Set the default function value to either 0, 0.0D0, .FALSE.,
        or blank depending on the type of the function.

    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 (WLT) (IMU) (HAN)