C Library Functions - rank_decreasing (3)

NAME

Rank_Decreasing(3f) - [M_orderpack:RANK:UNIQUE] ranks an array in decreasing order, with duplicate entries assigned the same rank(Merge-Sort)

Synopsis
Description
Options
Examples
Author
Maintainer
License

SYNOPSIS

Subroutine Rank_Decreasing (INVALS, IGOEST)
      ${TYPE} (kind=${KIND}), Intent (In) :: INVALS(:)
      Integer, Intent (Out)               :: IGOEST(:)
Where ${TYPE}(kind=${KIND}) may be

o Real(kind=real32)

o Real(kind=real64)

o Integer(kind=int16)

o Integer(kind=int32)

o Integer(kind=int64)

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

DESCRIPTION

RANK_DECREASING(3f) generates an inverse ranking of an array, but with duplicate entries assigned the same rank.
Internally, the routine is similar to pure merge-sort ranking, but on the last pass, it sets indices in IGOEST to the rank of the original value in an ordered set with duplicates removed. For performance reasons, the first two passes are taken out of the standard loop, and use dedicated coding.

OPTIONS

INVALS array to rank

IGOEST returned rank array

EXAMPLES

Sample program:

   program demo_rank_decreasing
   ! rank input array ranking duplicates the same
   use M_orderpack, only : rank_decreasing
   implicit none
   character(len=*),parameter :: fmt=’(a,*(g3.3,1x))’
   integer,allocatable,dimension(:) :: INVALS, igoest, distinct, count
   integer :: imx, i
      ! create an input array
      INVALS=[11, 11, 22, 11, 33, 33, 22, 33, 33]
      ! make an index array of the same size
      if(allocated(igoest))deallocate(igoest)
      allocate(igoest(size(INVALS)))
      print fmt, ’Original:                 ’,INVALS
      print fmt, ’Number of indices to sort:’,size(INVALS)
      ! rank input array ranking duplicates the same
      call rank_decreasing(INVALS,igoest)
      print fmt, ’Returned Indices:         ’,igoest(:)
      !
      ! interrogate the results
      !
      imx=maxval(igoest)
      print fmt, ’Number of unique indices :’,imx
      ! squeeze it down to just IMX unique values
      count=[(0,i=1,imx)] ! count how many times a value occurs
      distinct=count      ! array to set of unique values
      do i=1,size(INVALS)
         distinct(igoest(i))=INVALS(i)
         count(igoest(i))= count(igoest(i))+1
      enddo
      print fmt, ’Sorted unique values:     ’,distinct
      print fmt, ’count of occurrences:     ’,count
   end program demo_rank_decreasing

Results:

Original: 11 11 22 11 33 33 22 33 33 Number of indices to sort: 9 Returned Indices: 1 1 2 1 3 3 2 3 3 Number of unique indices : 3 Sorted unique values: 11 22 33 count of occurrences: 3 2 4

AUTHOR

Michel Olagnon, 2000-2012

MAINTAINER

John Urban, 2022.04.16

LICENSE

CC0-1.0

Nemo Release 3.1

rank_decreasing (3)

July 22, 2023

Generated by manServer 1.08 from 1071a31b-b77e-40fb-afda-fe9b91ce4387 using man macros.

o	Real(kind=real32)
o	Real(kind=real64)
o	Integer(kind=int16)
o	Integer(kind=int32)
o	Integer(kind=int64)
o	Character(kind=selected_char_kind("DEFAULT"),len=*)