what is the meaning of following code?

function [shift_rows_out] = shift_rows_fun (shift_rows_in)

idx = [1 2 3 4 6 7 8 5 11 12 9 10 16 13 14 15];

shift_rows_out = shift_rows_in(:, idx);

Answer 1

[madhan ravi]

You need to start learning the basics of matlab :

https://www.mathworks.com/company/newsletters/articles/matrix-indexing-in-matlab.html

Answer 2

[Image Analyst]

It extracts columns 1 2 3 4 6 7 8 5 11 12 9 10 16 13 14 and 15, in that order, from matrix "shift_rows_in" and puts the result into a new matrix called "shift_rows_out".

The colon in (:, idx) literally means "ALL rows" and the idx means indexes and since it's the second argument it means the column indexes specified by the poorly-named idx variable.