How to view/plot decomposed matrix from decomposition function

I'm using MATLAB's new decomposition function. For example, matrix L may be decomposed to dL as

 dL = decomposition(L);

However, in the data for the variable dL, I cannot find the decomposed matrix itself. Why not? Where is it?

Answer 1

[Christine Tobler]

Hi,

I'm afraid the decomposition object does not provide access to the factors of the decomposition. This is because, depending on the input matrix L, a different decomposition is used (LU decomposition, QR decomposition, Cholesky decomposition, ...). These decompositions use different numbers and types of matrices (P*L*U, Q*R*P, R'*R, ...), and can be represented in different ways (e.g., P can be a permutation matrix or a permutation vector).

Because of this, the decomposition object only supports linear system solving with the original matrix. To access the factors of the decomposition, call the specific decomposition function (LU, QR, CHOL, ...), based on the type of the decomposition that was returned.