Matrix-valued random variates
December 1, 2021 — January 6, 2022
Distributions that support a random matrix. There are many of these, surely? There are some particularly useful ones that I have encountered.
The most common matrix RV distributions I see are over positive-definite matrices in particular, which can be valid covariance functions. We also look at rotation matrices and matrices with i.i.d. elements.
1 “Random matrices”
Despite the general-sounding name, this is frequently used for a specific degenerate case, where the elements are i.i.d. random. See random matrices.
2 LKJ
Probability distribution for positive definite correlation matrices, or in practice, for their Cholesky factors.
3 Matrix Gaussian
Should look them up in Gupta and Nagar (1999).
4 Matrix Gamma
Currently handled under gamma processes.
5 Wishart
6 Inverse Wishart
7 Random rotations
See random rotations.
8 Matrix-F
Also introduced in Stephen R. Martin, Is the LKJ(1) prior uniform? “Yes”.
9 Matrix Beta/Dirichlet
The two Wikipedia summaries are sparse:
Should look them up in Gupta and Nagar (1999).