how to create a matrix from a vector in this style

So I have a vector e.g

P = [0.9 0.8] 1x2 vector

My outcome has to become Q =

0.9000 0.8000 0 0 0

0 0.9000 0.8000 0 0

0 0 0.9000 0.8000 0

0 0 0 0.9000 0.8000

So basically the row represent a year forecast, and the number is a pattern that has to be applied.

so i have a bit difficulty transforming this P vector into such a format. i.e that whenever the vector is moved one column that it has to add a zero column or something. I am trying to do this without for loops obviously.

best

Answer 1

[Jan]

P = [0.9, 0.8];
n = 4;
m = n*n + n;
Q = zeros(n, n + 1);
Q(  1:1+n:m) = P(1);
Q(n+1:1+n:m) = P(2);

or:

Q = reshape(repmat([P(1), zeros(1, n-1), P(2)], 1, n), n, []);

I assume the first one is more efficient.