How can I get matrix U from the equation below?
$$X=UD(U^TU)^{-1}D^TU^T$$
Where X is $n\times n$, D is $p\times p$ and U is $n\times p$. X and D are known and I want to solve for U. I think I sort of have to use SVD or Cholesky decomposition but I don't know how!
I appreciate any help or hint where I can start from!