C Library Functions - sort_special (3)

NAME

sort_special(3f) - [M_orderpack:SORT] Sorts array into ascending order (Insertion sort, generally for small or nearly sorted arrays)

Synopsis
Description
Options
Examples
Author
Maintainer
License

SYNOPSIS

Subroutine Sort_Special (INOUTVALS)
      ${TYPE} (kind=${KIND}), Intent (InOut) :: INOUTVALS(:)
Where ${TYPE}(kind=${KIND}) may be

o Real(kind=real32)

o Real(kind=real64)

o Integer(kind=int32)

o Character(kind=selected_char_kind("DEFAULT"),len=*)

DESCRIPTION

Sorts INOUTVALS() into ascending order (Insertion sort).
If certain requirements are met and performance is important this procedure can be far faster, but SORT(3f) and ranking routines RANK(3f) and RANK_BASIC(3f) are recommended for the general case.
This subroutine uses an Insertion sort. It does not use any work array and is faster when INOUTVALS() is of very small size (< 20), or already almost sorted; but worst case behavior can be triggered by commonly encountered data order (e.g. initially inverse sorted). Therefore, in many cases the Quick-sort or Merge-sort method is faster.

OPTIONS

INOUTVALS
array to sort

EXAMPLES

Sample program:

   program demo_sort_special
   ! sort an array using insertion sort
   use,intrinsic :: iso_fortran_env, only : int32, real32, real64
   use M_orderpack, only : sort_special
   implicit none
   ! an insertion sort is very efficient for very small arrays
   ! but generally slower than methods like quick-sort and merge-sort.
   integer,parameter :: isz=2000
   real(kind=real64) :: dd(isz), hi, low
      ! make an array of random values
      call random_seed()
      call random_number(dd)
      dd=dd*1000000.0-500000.0
      low= minval(dd)
      hi = maxval(dd)
      ! sort the data
      call sort_special(dd)
      ! cursory checks
      if(any(dd(1:isz-1) .gt. dd(2:isz)))stop ’ERROR: array not sorted’
      write(*,*)’check min:’,dd(1).eq.low
      write(*,*)’check max:’,dd(isz).eq.hi
      write(*,*)’PASSED: random array is now sorted’
   end program demo_sort_special

Results:

check min: T check max: T PASSED: random array is now sorted

AUTHOR

Michel Olagnon - Apr. 2000

MAINTAINER

John Urban, 2022.04.16

LICENSE

CC0-1.0

Nemo Release 3.1

sort_special (3)

July 22, 2023

Generated by manServer 1.08 from 04c47b77-9193-44d7-8979-a6b7f7865b5e using man macros.

o	Real(kind=real32)
o	Real(kind=real64)
o	Integer(kind=int32)
o	Character(kind=selected_char_kind("DEFAULT"),len=*)