[MsSparse] is the concrete [MsEngine] spec for penalized sparse NMF extraction (U-M2-05): `"volume"` = KL likelihood with a log-det volume regularizer on W (Leplat-Gillis-Ang), `"l1"` = KL with L1 penalties on both factors (Hoyer/Cichocki KL-L1L1 MU; SparseSignatures itself is least-squares + LASSO — attribution erratum in engine/sparse.rs). mu = 0 degenerates). Build one with [ms_sparse()]. Violations raise `msuiter_error_engine`.
Arguments
- name
registry key; fixed to `"sparse"`.
- mode
spec mode; fixed to `"extract"`.
- params
named list of hyper-parameters (empty: the sparse hyper-parameters live in the dedicated properties below).
- deterministic
always TRUE: the kernel is seeded and deterministic.
- packages
character vector of required R packages; none.
- label
human-readable engine label.
- variant
`"volume"` or `"l1"`.
- lambda
penalty on the signatures (volume strength / H-row L1).
- mu
W-column L1 penalty (l1 variant only; must be > 0 there — mu = 0 degenerates the exposure scale).
- delta
volume regularizer ridge (volume variant only; 0 picks the kernel default 1).
- tol
convergence tolerance on the relative objective change.
- max_iter
single positive whole number of update iterations.
- seed
single whole number in `[0, 2^31 - 1]`.