What's the best way to create a vector with a repeating and diminutive sequence?

For a small example, how to create a version of this, with a longer seequence. These are integers of equal length apart:

v = 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 1 2 ....

and the starting sequence length will be scaled up into the 100s or 1000s.

Any thoughts?

Answer 1

[Matt Fig]

N = 6;
A = cumsum(tril(ones(N,'single')));
A = A(A>0).';

If memory is a concern, this will conserve it:

L = (N^2+N)/2;
B = ones(1,L);
idx = (1:N).*((1:N)-1)/2;
Li = length(idx);
B(idx(2:Li)) = -(1:Li-1);
B = cumsum(B(L:-1:1));

[Adam Quintero]

I see where the initial sequence length is, and I am wondering how it would work if I wanted the sequence to decrease from the origin.

So:

v= [1 2 3 4 5 6 2 3 4 5 6 3 4 5 6 4 5 6 5 6 6]

I tried changing the sign of the 6 and the A>0 to A<0, and they didn't work. I think it shows here that I have a lot to learn. I appreciate the patience of anyone with feedback on this.

Thanx

[Matt Fig]

In that case, just reverse the order of two operations:

A = tril(cumsum(ones(N,'single')));