C Library Functions - medianval (3)
NAME
medianval(3f) - [M_orderpack:MEDIAN] Returns median VALUE.
CONTENTS
Synopsis
Description
Options
Returns
Examples
Author
Maintainer
License
SYNOPSIS
Recursive Function MedianVal (INVALS) Result (RES_MED)
${TYPE} (kind=${KIND}), Intent (In) :: INVALS(:) ${TYPE} (kind=${KIND}) :: RES_MEDWhere ${TYPE}(kind=${KIND}) may be
o Real(kind=real32) o Real(kind=real64) o Integer(kind=int32)
DESCRIPTION
Finds out and returns the median (((Size(INVALS)+1))/2^th value) of INVALS.
Internally, it uses the recursive procedure described in Knuth, The Art of Computer Programming, vol. 3, 5.3.3 .
The procedure is linear in time, and does not require to be able to interpolate in the set as the one used in ORDERVAL(3f)/ORDERLOC(3f). It also has better worst case behavior than ORDERVAL(3f)/ORDERLOC(3f), and is about 20% faster in average for random uniformly distributed values.
OPTIONS
INVALS input array
RETURNS
RES_MED the median value of the array INVALS
EXAMPLES
Sample program:
program demo_medianval ! return median value use M_orderpack, only : medianval implicit none character(len=*),parameter :: g=’(*(g0,1x))’ write(*,g)’real ’,& medianval( [80.0,70.0,20.0,10.0,1000.0] ) write(*,g)’integer’,& medianval( [11, 22, 33, 44, 55, 66, 77, 88] ) write(*,g)’double ’,& medianval( [11.0d0, 22.0d0, 33.0d0, 66.0d0, 77.0d0, 88.0d0] ) end program demo_medianvalResults:
real 70.00000 integer 44 double 33.00000000000000
AUTHOR
Michel Olagnon, 2000-2012
MAINTAINER
John Urban, 2022.04.16
LICENSE
CC0-1.0
| Nemo Release 3.1 | medianval (3) | February 23, 2025 |
