- Abstract
Do a binary search for a given value within an integer array,
accompanied by an order vector. Return the index of the
matching array entry, or -1 if the key value is not found.
- Required_Reading
None.
- 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.
order I Order vector.
The function returns the index of value in array, or -1 if the value
is not found.
- Detailed_Input
value is the value to be found in the input array.
ndim is the number of elements in the input array.
array is the array to be searched.
order is an order vector which can be used to access the elements
of array in order. The contents of order are a permutation
of the sequence of integers ranging from zero to ndim-1.
- Detailed_Output
The function returns the index of the input value in the input array.
Indices range from zero to ndim-1.
If the input array does not contain the specified value, the function
returns -1.
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.
- Particulars
A binary search is performed on the input array, whose order is given
by an associated order vector. 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, -1 is returned.
- Examples
Let array and order contain the following elements:
array order
----------- -----
100 1
1 2
10 0
10000 4
1000 3
Then
bschoi_c ( 1000, 5, array, order ) == 4
bschoi_c ( 1, 5, array, order ) == 1
bschoi_c ( 10000, 5, array, order ) == 3
bschoi_c ( -1, 5, array, order ) == -1
bschoi_c ( 17, 5, array, order ) == -1
That is,
array[4] == 1000
array[1] == 1
array[3] == 10000
- Restrictions
The input order vector is assumed give the order of the elements of the
input array in increasing order. If this condition is not met, the
results of bschoi_c are unpredictable.
- Exceptions
1) If memory cannot be allocated to create a Fortran-style version of
the input order vector, the error SPICE(MALLOCFAILED) is signaled.
The function returns -1 in this case.
2) If ndim < 1 the value of the function is -1. This is not an error.
- Files
None.
- Author_and_Institution
N.J. Bachman (JPL)
W.L. Taber (JPL)
I.M. Underwood (JPL)
- Literature_References
None.
- Version
-CSPICE Version 1.0.0, 10-JUL-2002 (NJB) (WLT) (IMU)
- Index_Entries
binary search for an integer value
- Link to routine source