What is the equation for sortrows

Hi,

I was wondering what the equivalent equation for (sortrows) in Matlab. Let's say:

B = sortrows(A,2)

If there is an idea, I really appreciate because I just want to understand the concept mathematically

[Rik]

You mean what the specific algorithm is that Mathworks used to implement this? They will probably not tell you.

And there is a difference between algorithm and equation.

What sortrows is doing (or something equivalent) is this:

function B=equivalent_to_sortrows(A,col)
[~,sort_order]=sort(A(:,col));
B=A(sort_order,:);
end

So the meat of the algorithm is just a sort.

[Rik]

Please post your comment as a comment, and not in the answer field. Their order can change, which makes reading the thread very confusing later on.

As far as I know there is not an equation that describes a sort algorithm, other than the trivial solution:

B=f(A,c)
where f sorts A according to column c

which would be a valid mathematical description, but would tell you anything.

Answer 1

[Isaac Adam]

Thanks a lot for the reply. Yes, I'm looking for a simple equation let's say I have a matrix of point A and I create a new matrix called B, then the sorting

B = sortrows(A,2);

so the row sorting is done s based on the second column. Is there any way to express this in equation format.