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 gfrefn_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

       gfrefn_c ( GF, default refinement estimator )

       void gfrefn_c ( SpiceDouble     t1,
                       SpiceDouble     t2,
                       SpiceBoolean    s1,
                       SpiceBoolean    s2,
                       SpiceDouble   * t  )

#### Abstract

       Estimate, using a bisection method, the next abscissa value at
       which a state change occurs. This is the default GF refinement
       method.

#### Required_Reading

       None.

#### Keywords

       SEARCH
       UTILITY

#### Brief_I/O

       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       t1         I   One of two values bracketing a state change.
       t2         I   The other value that brackets a state change.
       s1         I   State at `t1'.
       s2         I   State at `t2'.
       t          O   New value at which to check for transition.

#### Detailed_Input

       t1          is one of two abscissa values (usually times)
                   bracketing a state change.

       t2          is the other abscissa value that brackets a state change.

       s1          is the system state at `t1'. This argument is provided
                   for forward compatibility; it's not currently used.

       s2          is the system state at `t2'. This argument is provided
                   for forward compatibility; it's not currently used.

#### Detailed_Output

       t           is the midpoint of `t1' and `t2'.

#### Parameters

       None.

#### Exceptions

       Error free.

#### Files

       None.

#### Particulars

       "Refinement" means reducing the size of a bracketing interval on
       the real line in which a solution is known to lie. In the GF
       setting, the solution is the time of a state transition of a
       binary function.

       This routine supports solving for locations of bracketed state
       transitions by the bisection method. This is the default
       refinement method used by the GF system.

       The argument list of this routine is compatible with the GF
       system's general root finding routine. Refinement routines created
       by users must have the same argument list in order to be used by
       the GF mid-level APIs such as gfocce_c and gffove_c.

#### Examples

       The following code fragment from an example program in the header of
       gfocce_c shows the address of this routine passed as the 12th argument.

          /.
          Perform the search.
          ./
          gfocce_c ( "ANY",
                     "MOON",     "ellipsoid",  "IAU_MOON",
                     "SUN",      "ellipsoid",  "IAU_SUN",
                     "LT",       "EARTH",      CNVTOL,
                     &gfstep_c,  &gfrefn_c,    rpt,
                     &gfrepi_c,  &gfrepu_c,    &gfrepf_c,
                     bail,       &gfbail_c,    &cnfine,
                     &result                              );

#### Restrictions

       None.

#### Literature_References

       None.

#### Author_and_Institution

       N.J. Bachman        (JPL)
       J. Diaz del Rio     (ODC Space)
       E.D. Wright         (JPL)

#### Version

       -CSPICE Version 1.0.1, 01-NOV-2021 (JDR)

           Edited the header to comply with NAIF standard.

       -CSPICE Version 1.0.0, 15-APR-2009 (NJB) (EDW)

#### Index_Entries

       GF standard step refinement

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

    Fri Dec 31 18:41:07 2021