how can i swap the matrix element using control statements or any built in functions?

i have a square matrix m*n, (256*256). i am looking for functions (forward and reverse) to swaps elements until the bottom-right corner remain with lower values than any other part of the matrix, and and the top-left corner with high values. example

A=[6 5;4 7] become B=[7 6;5 4]; or  D=[10 20 50 60;33 55 44 100; 3 6 12 9;4 2 1 3] become E=[100 60 55 50; 44 33 20 12;10 9 6 4;3 3 2 1];

here are sample of the code I design which does not provide the answer as i needed when i applied to 256*256 matrix.

a= [6 5;4 7];
[ b ] = swaps( a );
disp(b);



function [ b ] = swaps( a )

[m,n]=size(a);

for i=1:m
    for j=1:n
        temp=zeros();
        if a([i,j]) >= a([i,j+1])
            a([i,j])=a([i,j]);
        else
            temp(i,j)=a(i,j);
            a(i,j)=a(i,j+1);
            a(i,j+1)=temp(i,j);
            
            if a([i,j+1]) >= a([i,j+1])
                a([i,j+1])=a([i,j+1]);
            else
                temp([i,j+1])=a([i,j+1]);
                a([i,j+1])=a([i+1,j+1]);
                a([i+1,j+1])=temp([i,j+1]);  
            end
        end
    end
end

i thought the same method used to access element in other programming language could be applicable in MATLAB, by referencing the element in terms of (i,j) and encrements when needed.

Can any one help me on that?

Answer 1

[Ameer Hamza]

You can just use sort() with reshape()

D = [10 20 50 60;33 55 44 100; 3 6 12 9;4 2 1 3]
E = reshape(sort(D(:), 'descend'), size(D)).'

Result

>> E
E =
   100    60    55    50
    44    33    20    12
    10     9     6     4
     3     3     2     1

[dani elias]

Thank you, but is it possible to return into original vector?

[Ameer Hamza]

You can get back D like this:

D = [10 20 50 60;33 55 44 100; 3 6 12 9;4 2 1 3];

[S, idx] = sort(D(:), 'descend');
E = reshape(S, size(D)).';

D_new = zeros(size(E));
D_new(idx) = S;

[dani elias]

Thank you... I do appreciate a lot. Thank you, once again.

[Ameer Hamza]

I am glad to be of help!