Sorting matrix with specifications for the order

Hi,

I have a certain matrix with n rows and 3 columns. I want to sort it according to the sums of the squares of its columns.

For example, let's say my matrix is

0 0 1

0 0 2

1 1 1

Since for the second row we have: 0^2+0^2+2^2 = 4, which is larger than the 3rd row: 1^2+1^2+1^2 = 3. In such a case, I want my matrix to look like:

0 0 1

1 1 1

0 0 2

Thank you for your help, it is very appreciated !

Answer 1

[Azzi Abdelmalek]

A=[0 0 1;0 0 2;1 1 1];
[~,idx]=sort(sum(A.^2,2))
out=A(idx,:)

[Jan]

This is faster than the arrayfun approach, but of course this matters for larger matrices only.

Answer 2

[Yowh]

Here .. I think this will work ..

A = [0 0 1;0 0 2;1 1 1;0 0 0];
ans = sortrows(A, [3 2 1])