Element-wise cross-validation for nmfkc.net (upper-triangle folds)

k-fold CV with folds taken over the upper triangle of the symmetric \(Y\) (mirrored to the lower triangle) to prevent information leakage through symmetry. A single entry point covers all three symmetric NMF variants; type selects the fitting function:

• "tri" (default): nmfkc.net with \(C \ge 0\)

• "bi": nmfkc.net with \(C = I_Q\)

• "signed": nmfkc.net with signed \(C = C_{+} - C_{-}\)

Usage

nmfkc.net.ecv(Y, rank = 1:3, type = c("tri", "bi", "signed"), ...)

Arguments

Y

Symmetric N x N non-negative matrix.

rank

Integer vector of ranks to evaluate. Default 1:3.

type

Model type: "tri" (default), "bi", or "signed".

...

Passed to the underlying fitter; also accepts nfolds (default 5; div alias), seed (default 123), and cores (getOption("mc.cores", 1L)) to evaluate the rank x fold grid in parallel; results are identical to the sequential run for any cores (PSOCK cluster on Windows, forking elsewhere).

Value

A list with objfunc, sigma, objfunc.fold, folds, Q.grid, type.

Lifecycle

This function is experimental. The interface may change in future versions; details are to be described in an upcoming paper.

See also

nmfkc.net