how to create increasing number pyramid matrix?

hello,

how do I create a matrix of the form:

1  2 3 4 5
6  7 8 0 0
9 10 0 0 0
11 0 0 0 0 

in this example N=5. I need a solution for any N.

EDIT:

I'm performing manual clustering. in this example of five points. points 1&2 have been clustered together to a new point - 6. points 3&4 have been clustered together to a new point - 7. points number 5 was reassigned to point 8, and so on.

thanks

[Stephen23]

Please explain your example matrix. You write that "in this example N=5", so what determines that there should only be four rows? Why is the second row apparently missing?: if we count the number of zeros in each row, we get this:

1  2 3 4 5  -> 0
6  7 8 0 0  -> 2
9 10 0 0 0  -> 3
11 0 0 0 0  -> 4

Where is the row with just one 0?

[yonatan s]

i've edited the question, hope it is clear now

[Rik]

Or is this the N=6 output?

1  2  3 4 5 6
7  8  9 0 0 0
10 11 0 0 0 0
12 0  0 0 0 0

(halving the number of non-zero elements on each row (rounding up), making each non-zero element a unique value)

Answer 1

[Rik]

In case that is the pattern you're looking for, here is the code that implements it:

function M=create_stairs_matrix(N)
M=zeros(N,1);M(1)=N;n=1;%prepare for loop
while M(n)>1
    %halve number of elements (rounding up) until 1 is reached
    M(n+1)=ceil(M(n)/2);
    n=n+1;
end
M((n+1):end)=[];%remove empty rows
nonzeroelems=sum(M);

%mark the number of elements to be filled with a true
M=(1:N)<=M;%implicit expansion (use bsxfun on <R2016b)
M=double(M');
M(logical(M))=1:nonzeroelems;
M=M';
end

[yonatan s]

perfect. thank you