# what does “D = diag(W.1)” means?

, what does “D = diag(W.1)” means?on page #2, just below equation (6) PFA screenshot and here is the link of the paper - original paper

• – Rodrigo de Azevedo Jul 11 '19 at 10:30
• It already has answers there, please don't cross-post. That way, you don't waste people's time. – nicoguaro Jul 11 '19 at 14:00

I believe that $$\mathbf W\cdot \mathbf 1$$ denotes a matrix-vector product of a matrix $$\mathbf W$$ with a vector of ones $$\mathbf 1$$ of the corresponding size (number of columns).
The result of this operation is a vector (of the size of number of rows of $$\mathbf W$$), so, it makes total sense to apply a diagonal function on it to arrive to a matrix form.