The NMF package defines methods for the generic deviance from the package stats,
to compute approximation errors between NMF models and matrices, using a variety of
objective functions.
nmfDistance returns a function that computes the distance between an NMF model and a
compatible matrix.
deviance(object, ...) S4 (NMF) `deviance`(object, y, method = c("", "KL", "euclidean"), ...) nmfDistance(method = c("", "KL", "euclidean")) S4 (NMFfit) `deviance`(object, y, method, ...) S4 (NMFStrategy) `deviance`(object, x, y, ...)
object, i.e. y
must have the same dimension as fitted(object).(x="NMF", y="matrix", ...) that implements a distance measure between
an NMF model x and a target matrix y, i.e. an objective function
to use to compute the deviance.
In deviance, it is passed to nmfDistance to get the function
that effectively computes the deviance.y.deviance returns a nonnegative numerical value
nmfDistance returns a function with least two arguments:
an NMF model and a matrix.
signature(object = "NMF"): Computes the distance between a matrix and the estimate of an NMF model.
signature(object = "NMFfit"): Returns the deviance of a fitted NMF model.
This method returns the final residual value if the target matrix y is
not supplied, or the approximation error between the fitted NMF model stored
in object and y.
In this case, the computation is performed using the objective function
method if not missing, or the objective of the algorithm that
fitted the model (stored in slot 'distance').
If not computed by the NMF algorithm itself, the value is automatically
computed at the end of the fitting process by the function nmf,
using the objective function associated with the NMF algorithm, so that it
should always be available.
signature(object = "NMFfitX"): Returns the deviance achieved by the best fit object, i.e. the lowest
deviance achieved across all NMF runs.
signature(object = "NMFStrategy"): Computes the value of the objective function between the estimate x
and the target y.