ordd_c

Index Page ordd_c
A B C D E F G H I J K L M N O P Q R S T U V W X
Procedure Abstract Required_Reading Keywords Brief_I/O Detailed_Input | Detailed_Output Parameters Exceptions Files Particulars Examples | Restrictions Literature_References Author_and_Institution Version Index_Entries
#### Procedure
       SpiceInt ordd_c ( SpiceDouble     item,
                         SpiceCell     * set  )
#### Abstract
       The function returns the ordinal position of any given item in a
       double precision set.  If the item does not appear in the set, the
       function returns -1.
#### Required_Reading
       SETS
#### Keywords
       SEARCH
       SETS
#### Brief_I/O
       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       item       I   An item to locate within a set.
       set        I   A set to search for a given item.

       The function returns the ordinal position of item within the set.
#### Detailed_Input
       item      is a double precision number to be located within a set.

       set       is a double precision CSPICE set that is to be searched
                 for the occurrence of item.

                 set must be declared as a double precision SpiceCell.
#### Detailed_Output
       The function returns the ordinal position of item within set.
       Ordinal positions range from 0 to N-1, where N is the cardinality
       of the set.

       If item is not an element of set, the function returns -1.
#### Parameters
       None.
#### Exceptions
       1) If the input set argument is a SpiceCell of type other than
          double precision, the error SPICE(TYPEMISMATCH) is signaled.

       2) If the input set argument does not qualify as a CSPICE set,
          the error SPICE(NOTASET) will be signaled.  CSPICE sets have
          their data elements sorted in increasing order and contain
          no duplicate data elements.
#### Files
       None.
#### Particulars
       A natural ordering can be imposed upon the elements of any
       CSPICE set, be it integer, character or double precision.  For
       character strings the ASCII collating sequence serves as the
       ordering relation, for double precision and integer variables
       the arithmetic ordering is used.

       Given any element of a set, its location within this ordered
       sequence of elements is called its ordinal position within
       the set.

       In common mathematical usage, ordinal positions of elements
       in a set of cardinality N range from 1 to N.  In C programs,
       it is much more convenient to use the range 0 to N-1; this is
       the convention used in CSPICE.

       For illustrative purposes suppose that set represents the set

          { 8, 1, 2, 9, 7, 4, 10 }

       The ordinal position of:

           8 is 4
           1 is 0
           2 is 1
           9 is 5
           7 is 3
           4 is 2
          10 is 6
#### Examples
       1) Obtain the ordinal positions shown in the table of the Particulars
          section above.

             #include "SpiceUsr.h"

             int main()
             {
                /.
                Declare a double precision set and populate it with
                the elements shown above.
                ./
                #define MAXSIZ         7

                SPICEDOUBLE_CELL ( set, MAXSIZ );

                SpiceDouble            inputs [MAXSIZ] =
                                       {
                                          8.0, 1.0, 2.0, 9.0, 7.0, 4.0, 10.0
                                       };

                SpiceDouble            expected [MAXSIZ] =
                                       {
                                          4.0, 0.0, 1.0, 5.0, 3.0, 2.0, 6.0
                                       };

                SpiceInt               i;
                SpiceDouble            dElt;

                /.
                Create the set.
                ./

                for ( i = 0;  i < MAXSIZ;  i++ )
                {
                   insrtd_c ( inputs[i], &set );
                }

                /.
                Examine the ordinal positions of the set's elements.
                Extract each element and verify that ordd_c gives the
                index at which the element is located.
                ./

                for ( i = 0;  i < card_c(&set);  i++ )
                {
                   dElt = inputs[i];

                   if (  ordd_c(dElt, &set)  !=  expected[i]  )
                   {
                      setmsg_c ( "Position of # was expected to be # "
                                 "but was actually #."                 );
                      errdp_c  ( "#",  dElt                            );
                      errdp_c  ( "#",  expected[i]                     );
                      errint_c ( "#",  ordd_c(dElt,&set)               );
                      sigerr_c ( "INVALID LOCATION"                    );
                   }
                }

                return ( 0 );
             }
#### Restrictions
       None.
#### Literature_References
       None.
#### Author_and_Institution
       N.J. Bachman    (JPL)
       C.A. Curzon     (JPL)
       H.A. Neilan     (JPL)
       W.L. Taber      (JPL)
       I.M. Underwood  (JPL)
#### Version
       -CSPICE Version 1.0.0, 07-AUG-2002 (NJB) (CAC) (HAN) (WLT) (IMU)
#### Index_Entries
       the ordinal position of an element in a set
#### Link to routine ordd_c source file ordd_c.c

    Thu Apr 16 08:58:44 2009