; NAME:
;   ARRAY_SCRAMBLE
;
; PURPOSE:
;   This function scrambles array elements to have array elements in new random order
;
; AUTHOR:
;   Sangwoo Lee, Ph.D.
;   SELab, Inc.
;   Seoul, Korea
;   Phone: 82-10-3727-1172
;   E-mail: lee@selab.co.kr
;   Blog : http//blog.daum.net/swrush
;
; USAGE:
;   ARRAY_SCRAMBLE, arr
;
; RETURN VALUE:
;   new array in new random order
;
; ARGUMENTS:
;   img : input array (any dimension, any size)
;
; Keywords:
;   None
;
; MODIFICATION HISTORY:
;   First written on Dec 31, 2019.
;
;******************************************************************************************
;  Copyright (c) 2019, by Sangwoo Lee and SELab, Inc.               ;
;  All rights reserved.
;******************************************************************************************

FUNCTION ARRAY_SCRAMBLE, arr

IF arr EQ !null THEN BEGIN
  PRINT, 'an input array is required!'
  RETURN, !null
ENDIF

n = N_ELEMENTS(arr)
arr_new = arr
inds = INDGEN(n)
inds_selected = INTARR(n)
REPEAT BEGIN
  ind = FIX(RANDOMU(seed, 1)*n)<(n-1)
  IF inds_selected[ind] EQ 1 THEN CONTINUE
  arr_new[TOTAL(inds_selected)-1] = arr[ind]
  inds_selected[ind] = 1
ENDREP UNTIL TOTAL(inds_selected) EQ n

RETURN, arr_new

END