Procedure

     BSRCHD ( Binary search for double precision value )

     INTEGER FUNCTION BSRCHD ( VALUE, NDIM, ARRAY )

Abstract

     Do a binary search for a given value within a double precision
     array, assumed to be in nondecreasing order. Return the index of
     the matching array entry, or zero if the key value is not found.

Required_Reading

     None.

Keywords

     ARRAY
     SEARCH

Declarations

     IMPLICIT NONE

     DOUBLE PRECISION   VALUE
     INTEGER            NDIM
     DOUBLE PRECISION   ARRAY ( * )

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     VALUE      I   Value to find in ARRAY.
     NDIM       I   Dimension of ARRAY.
     ARRAY      I   Array to be searched.

     The function returns the index of VALUE in ARRAY, or zero if not
     found.

Detailed_Input

     VALUE    is the double precision value to be found in the input
              array.

     NDIM     is the number of elements in the input array.

     ARRAY    is the double precision array to be searched. The
              elements in ARRAY are assumed to sorted in increasing
              order.

Detailed_Output

     The function returns the index of the specified value in the input
     array. Indices range from 1 to NDIM.

     If the input array does not contain the specified value, the
     function returns zero.

     If the input array contains more than one occurrence of the
     specified value, the returned index may point to any of the
     occurrences.

Parameters

     None.

Exceptions

     Error free.

     1)  If NDIM < 1, the value of the function is zero.

Files

     None.

Particulars

     A binary search is performed on the input array. If an element of
     the array is found to match the input value, the index of that
     element is returned. If no matching element is found, zero is
     returned.

Examples

     Let ARRAY contain the following elements:

             -11.D0
               0.D0
              22.491D0
             750.0D0

     Then

           BSRCHD ( -11.D0,    4, ARRAY )    = 1
           BSRCHD (  22.491D0, 4, ARRAY )    = 3
           BSRCHD ( 751.D0,    4, ARRAY )    = 0

Restrictions

     1)  ARRAY is assumed to be sorted in increasing order. If this
         condition is not met, the results of BSRCHD are unpredictable.

Literature_References

     None.

Author_and_Institution

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

Version

    SPICELIB Version 1.1.0, 26-OCT-2021 (JDR)

        Added IMPLICIT NONE statement.

        Edited the header to comply with NAIF standard. Removed
        unnecessary $Revisions section. Improved $Detailed_Output
        section.

    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)