IDL 双重排序函数
;+
; :Description:
; Double Sort
; :Input:
; input array dimensions: 2*N
; idx: 0 - Sort by the first column firstly (Default)
; 1 - Sort by the second column firstly
; type: 0 - ascending sort both columns (Default)
; 1 - descending sort both columns
; 2 - ascending sort firstly, and the descending sort
; 3 - descending sort firstly, and then ascending sort
; :Output:
; output sorted array: 2*N;
; :Example:
; arr = [[9,4],[3,4],[3,1],[2,6],[9,6],[3,5],[5,4]]
; arrNew = double_sort(arr, 1, 3)
; :Author: duhj@esrichina.com.cn
;-
FUNCTION DOUBLE_SORT, arr, idx, type
COMPILE_OPT idl2
print , n_elements(arr)
;
;判断输入数组是否为2*N
IF ~N_ELEMENTS(arr) THEN BEGIN
MESSAGE, 'Incorrect number of arguments', /continue
RETURN, !null
ENDIF ELSE BEGIN
IF (SIZE(arr, /DIMENSIONS))[0] NE 2 $
OR SIZE(arr, /N_DIMENSIONS) NE 2 THEN BEGIN
MESSAGE, 'Please input array with 2*N dimensions', /continue
RETURN, !null
ENDIF
ENDELSE
;判断按第几列排序，默认为0
; 0 --- 按第一列先排序
; 1 --- 按第二列先排序
IF ~N_ELEMENTS(idx) THEN BEGIN
idx = 0
ENDIF ELSE BEGIN
IF idx NE 0 AND idx NE 1 THEN BEGIN
MESSAGE, 'Input index must be one of the value:0,1', /continue
RETURN, !null
ENDIF
ENDELSE
;判断排序类型，降序or升序
; 0 - 均按升序排序
; 1 - 均按降序排序
; 2 - 首先按升序，然后按降序
; 3 - 首先按降序，然后按升序
IF ~N_ELEMENTS(type) THEN BEGIN
type = 0
ENDIF
arr1 = arr[1-idx,*]
arr2 = arr[idx,*]
CASE type OF
0: BEGIN
arr1sort = arr1[SORT(arr2)]
arr2sort = arr2[SORT(arr2)]
R = HISTOGRAM(arr2sort, location = loc)
eValue = loc[WHERE(HISTOGRAM(arr2sort) GT 1)]
FOREACH element, eValue DO BEGIN
eIdx = WHERE(arr2sort EQ element)
arr1sort[eIdx] = (arr1sort[eIdx])[SORT(arr1sort[eIdx])]
ENDFOREACH
END
1: BEGIN
arr1sort = REVERSE(arr1[SORT(arr2)])
arr2sort = REVERSE(arr2[SORT(arr2)])
R = HISTOGRAM(arr2sort, location = loc)
eValue = loc[WHERE(HISTOGRAM(arr2sort) GT 1)]
FOREACH element, eValue DO BEGIN
eIdx = WHERE(arr2[REVERSE(SORT(arr2))] EQ element)
arr1sort[eIdx] = (arr1sort[eIdx])[(REVERSE(SORT(arr1sort[eIdx])))]
ENDFOREACH
END
2: BEGIN
arr1sort = (arr1[SORT(arr2)])
arr2sort = (arr2[SORT(arr2)])
R = HISTOGRAM(arr2sort, location = loc)
eValue = loc[WHERE(HISTOGRAM(arr2sort) GT 1)]
FOREACH element, eValue DO BEGIN
eIdx = REVERSE(WHERE(arr2sort EQ element))
arr1sort[eIdx] = ((arr1sort[eIdx])[((SORT(arr1sort[eIdx])))])
ENDFOREACH
END
3: BEGIN
arr1sort = REVERSE(arr1[SORT(arr2)])
arr2sort = REVERSE(arr2[SORT(arr2)])
R = HISTOGRAM(arr2sort, location = loc)
eValue = loc[WHERE(HISTOGRAM(arr2sort) GT 1)]
FOREACH element, eValue DO BEGIN
eIdx = (WHERE(arr2sort EQ element))
arr1sort[eIdx] = ((arr1sort[eIdx])[((SORT(arr1sort[eIdx])))])
ENDFOREACH
END
ELSE: BEGIN
MESSAGE, 'Please input the correct argument of type.', /continue
RETURN, !null
END
ENDCASE
arrNew = arr
arrNew[1-idx,*] = arr1sort
arrNew[idx,*] = arr2sort
RETURN, arrNew
END
