Question

My problem is the following: I have a vector as

[3,4,5,6,7]

I want to create a matrix as

3 0 0 0 0   
3 4 0 0 0   
3 4 5 0 0   
3 4 5 6 0   
3 4 5 6 7 

However, I don’t want to use for loops because of the problem of size that I will eventually get.
I was thinking about using flipud, fliprl, hankel and toeplitz functions but cannot find a solution.

Answer 1

Try this:

x = [3,4,5,6,7]
tril(ones(length(x),1)*x)

ans =

 3     0     0     0     0
 3     4     0     0     0
 3     4     5     0     0
 3     4     5     6     0
 3     4     5     6     7