Example of Array Sorting Functions

Given,

  A = (/2,3,7,4,9,1,5,5,0,5,5/)

then GRADE_DOWN(A) is the 2D ( ) array:

  (/5,3,7,8,10,11,4,2,1,6,9/)

and

GRADE_UP(A,DIM=1) is the 1D array:

  (/9,6,1,2,4,7,8,10,11,3,5/)

Note how the multiple values of 5 are sorted.

If the DIM= specifier is not used then the result of these functions is always a 2D array (of coordinates) and has shape:

  (/ SIZE(SHAPE(A)),PRODUCT(SHAPE(A))/)

Otherwise the shape is the same as A.

Elements of the same value are ordered by their position in array element order. For the repeated value of 5 (which occurs four times in the source array), the result contains element 7 before element 8 which comes before element 10, and so on.

 

Consider a further example, if A is the 2D array:

    1 9 2
    4 5 2
    1 2 4

Then GRADE_DOWN(A) is (the coordinates)

    1 2 2 3 3 1 2 1 3
    2 2 1 3 2 3 3 1 1

Since A is a 2D array of 9 elements the result has 9 coordinates, ie 18 elements.

The DIM= specifier can be used: GRADE_DOWN(A,DIM=1) is

    2 1 3
    1 2 1
    3 3 2

The result GRADE_DOWN(A,DIM=1) is three columns, each containing the indices of the sorted elements for that column.

Now try this question

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