How to solve for $L$ in $X = LL^T$?

Question

I know I'm not the first to do this and I can't find what it's called that would tell me how to solve for $L$ when $X$ is a symmetric positive semidefinite. I know

orth(A)*transpose(orth(A)) = [Identity matrix] 

and

[q,r]=qr(A)
q*r == A

but I can't find $X = LL^T$. If anyone knows what the method is named/called that I could use to solve this it'd be really appreciated!

Answer 1

You're looking for Cholesky Factorization.