Index of Functions: A B C D E F G H I J K L M N O P Q R S T U V W X
Index Page wndifd_c

Table of contents

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

       wndifd_c ( Difference two DP windows )

       void wndifd_c (  SpiceCell   * a,
                        SpiceCell   * b,
                        SpiceCell   * c  )

#### Abstract

       Place the difference of two double precision windows into
       a third window.

#### Required_Reading

       WINDOWS

#### Keywords

       WINDOWS

#### Brief_I/O

       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       a,
       b          I   Input windows.
       c          O   Difference of `a' and `b'.

#### Detailed_Input

       a,
       b           are SPICE windows, each of which contains zero or more
                   intervals.

                   `a' and `b' must be declared as double precision SpiceCells.

                   CSPICE provides the following macros, which declare and
                   initialize the cells

                      SPICEDOUBLE_CELL        ( a, ASZ );
                      SPICEDOUBLE_CELL        ( b, BSZ );

                   where ASZ and BSZ are the maximum capacity of `a' and `b',
                   respectively.

#### Detailed_Output

       c           is the output SPICE window, containing the difference
                   of `a' and `b' --- every point contained in `a', but not
                   contained in `b'.

                   `c' must be distinct from both `a' and `b'.

                   `c' must be declared as a double precision SpiceCell.

                   CSPICE provides the following macro, which declares and
                   initializes the cell

                      SPICEDOUBLE_CELL        ( c, CSZ );

                   where CSZ is the maximum capacity of `c'.

#### Parameters

       None.

#### Exceptions

       1)  If the difference of the two windows results in an excess of
           elements, the error SPICE(WINDOWEXCESS) is signaled by a
           routine in the call tree of this routine.

       2)  The cardinality of the input windows must be even. Left
           endpoints of stored intervals must be strictly greater than
           preceding right endpoints. Right endpoints must be greater
           than or equal to corresponding left endpoints. Invalid window
           data are not diagnosed by this routine and may lead to
           unpredictable results.

       3)  If any the `a', `b' or `c' cell arguments has a type other
           than SpiceDouble, the error SPICE(TYPEMISMATCH) is signaled.

#### Files

       None.

#### Particulars

       Mathematically, the difference of two windows contains every
       point contained in the first window but not contained in the
       second window.

       C offers no satisfactory floating point representation
       of open intervals. Thus, for floating point windows we must
       return the closure of the set theoretical difference: that is,
       the difference plus the endpoints of the first window that are
       contained in the second window.

#### Examples

       Let a contain the intervals

          [ 1, 3 ]  [ 7, 11 ]  [ 23, 27 ]

       and b contain the intervals

          [ 2, 4 ]  [ 8, 10 ]  [ 16, 18 ]

       Then the difference of a and b contains the intervals

          [ 1, 2 ]  [ 7, 8 ]  [ 10, 11 ]  [ 23, 27 ]

#### Restrictions

       None.

#### Literature_References

       None.

#### Author_and_Institution

       N.J. Bachman        (JPL)
       J. Diaz del Rio     (ODC Space)
       H.A. Neilan         (JPL)
       B.V. Semenov        (JPL)
       W.L. Taber          (JPL)
       I.M. Underwood      (JPL)

#### Version

       -CSPICE Version 1.0.2, 24-AUG-2021 (JDR)

           Edited the header to comply with NAIF standard. Added entry #3
           in -Exceptions section.

           Extended description of arguments "a", "b" and "c" to include
           type and preferred declaration method.

           Improved -Particulars section.

       -CSPICE Version 1.0.1, 11-FEB-2013 (BVS)

           Corrected typo in Brief I/O section.

       -CSPICE Version 1.0.0, 29-JUL-2002 (NJB) (HAN) (WLT) (IMU)

#### Index_Entries

       difference two d.p. windows

#### Link to routine wndifd_c source file wndifd_c.c

    Fri Dec 31 18:41:15 2021