Vectorization of for loop

I have this for loop with conditionals inside it.

for i=1:m
    for j=1:n
        if (flipped_im(i,j,1)>flipped_im(i,j,2)) || (flipped_im(i,j,1)>flipped_im(i,j,3))
            mod_im(i,j,:)=255;
        else
            mod_im(i,j,:)=flipped_im(i,j,:);
        end
    end
end

How I can turn this loop into vectorized code?

[Stephen23]

"How I can turn this loop into vectorized code?"

Why do you need to do that?

[Yaser Alghawi]

It is an assignment. To optimize the speed of the program.

Answer 1

[Stephen23]

In three lines, no loop:

>> new_im = flipped_im;
>> idx = new_im(:,:,1)>new_im(:,:,2) | new_im(:,:,1)>new_im(:,:,3);
>> new_im(idx(:,:,[1,1,1])) = 255;

and checking:

>> isequal(mod_im,new_im)
ans = 1

For MATLAB versions R2016b and later you can simplify the index code:

idx = any(new_im(:,:,1)>new_im(:,:,2:3),3);

[Jan]

Or in < R2016b:

idx = any(new_im(:,:, [1, 1]) > new_im(:,:, 2:3), 3);

Answer 2

[Yaser Alghawi]

Thank you Chris and Jan. It did the trick.

[Stephen23]

Who is Chris?